2.7.7.72 a tRNA precursor + 2 CTP + ATP - Arabidopsis thaliana a tRNA with a 3'CCA end + 3 diphosphate - ? 420160 2.7.7.72 a tRNA precursor + 2 CTP + ATP - Saccharolobus shibatae a tRNA with a 3'CCA end + 3 diphosphate - ? 420160 2.7.7.72 a tRNA precursor + 2 CTP + ATP - Escherichia coli a tRNA with a 3' CCA end + 3 diphosphate - r 421833 2.7.7.72 a tRNA precursor + 2 CTP + ATP - Homo sapiens a tRNA with a 3' CCA end + 3 diphosphate - r 421833 2.7.7.72 a tRNA precursor + 2 CTP + ATP - Homo sapiens a tRNA with a 3' CCA end + 3 diphosphate - ? 421833 2.7.7.72 a tRNA precursor + 2 CTP + ATP - Archaeoglobus fulgidus a tRNA with a 3' CCA end + 3 diphosphate - ? 421833 2.7.7.72 a tRNA precursor + 2 CTP + ATP - Saccharomyces cerevisiae a tRNA with a 3' CCA end + 3 diphosphate - ? 421833 2.7.7.72 a tRNA precursor + 2 CTP + ATP overall reaction Saccharolobus shibatae a tRNA with a 3' CCA end + 3 diphosphate - ? 421833 2.7.7.72 a tRNA precursor + 2 CTP + ATP substrate is synthetic DNA templates based on the sequence of Escherichia coli tRNAVal. Overall reaction Archaeoglobus fulgidus a tRNA with a 3' CCA end + 3 diphosphate - r 421833 2.7.7.72 a tRNA precursor + 2 CTP + ATP substrate is synthetic DNA templates based on the sequence of Escherichia coli tRNAVal. Overall reaction, class II CCA-adding enzymes also perform the reverse reaction, mechanism, overview. The enzyme catalyzes diphosphorolysis slowly relative to the forward nucleotide addition and that it exhibits weak binding affinity to diphosphate relative to NTP Escherichia coli a tRNA with a 3' CCA end + 3 diphosphate - r 421833 2.7.7.72 a tRNA precursor + 2 CTP + ATP substrate is synthetic DNA templates based on the sequence of Escherichia coli tRNAVal. Overall reaction, class II CCA-adding enzymes also perform the reverse reaction, mechanism, overview. The enzyme catalyzes diphosphorolysis slowly relative to the forward nucleotide addition and that it exhibits weak binding affinity to diphosphate relative to NTP Homo sapiens a tRNA with a 3' CCA end + 3 diphosphate - r 421833 2.7.7.72 a tRNA precursor + 2 CTP + ATP the 30-region of RNA is proofread, after two nucleotide additions, in the closed, active form of the complex at the AMP incorporation stage. This proofreading is a prerequisite for the maintenance of fidelity for complete CCA synthesis Archaeoglobus fulgidus a tRNA with a 3' CCA end + 3 diphosphate - ? 421833 2.7.7.72 a tRNA precursor + 2 CTP + ATP one catalytic center is responsible for addition of both CTP and ATP. As the single active site catalyzes addition of each nucleotide, the growing 3'-end of the tRNA would progressively refold to create a binding pocket for addition of the next nucleotide Saccharolobus shibatae a tRNA with a 3' CCA end + 3 diphosphate - ? 421833 2.7.7.72 a tRNA precursor + 2 CTP + ATP tRNA does not rotate or translocate during C74 addition. A single flexible beta-turn orchestrates consecutive addition of all three nucleotides without significant movement of the tRNA on the enzyme surface Archaeoglobus fulgidus a tRNA with a 3' CCA end + 3 diphosphate - ? 421833 2.7.7.72 a tRNA precursor + 2 CTP + ATP - Saccharomyces cerevisiae ATCC 204508 a tRNA with a 3' CCA end + 3 diphosphate - ? 421833 2.7.7.72 a tRNA precursor + CTP - Saccharolobus shibatae a tRNA with a 3' cytidine end + diphosphate - ? 425862 2.7.7.72 a tRNA precursor + CTP C74 addition Archaeoglobus fulgidus a tRNA with a 3' cytidine end + diphosphate - ? 425862 2.7.7.72 a tRNA precursor + CTP one catalytic center is responsible for addition of both CTP and ATP. As the single active site catalyzes addition of each nucleotide, the growing 3'-end of the tRNA would progressively refold to create a binding pocket for addition of the next nucleotide Saccharolobus shibatae a tRNA with a 3' cytidine end + diphosphate - ? 425862 2.7.7.72 a tRNA with a 3' CC end + ATP - Saccharolobus shibatae a tRNA with a 3' CCA end + diphosphate - ? 422718 2.7.7.72 a tRNA with a 3' CC end + ATP - Archaeoglobus fulgidus a tRNA with a 3' CCA end + diphosphate - ? 422718 2.7.7.72 a tRNA with a 3' CC end + ATP A76 addition Archaeoglobus fulgidus a tRNA with a 3' CCA end + diphosphate - ? 422718 2.7.7.72 a tRNA with a 3' CC end + ATP one catalytic center is responsible for addition of both CTP and ATP. As the single active site catalyzes addition of each nucleotide, the growing 3'-end of the tRNA would progressively refold to create a binding pocket for addition of the next nucleotide Saccharolobus shibatae a tRNA with a 3' CCA end + diphosphate - ? 422718 2.7.7.72 a tRNA with a 3' CCA end + 3 diphosphate - Escherichia coli a tRNA precursor + 2 CTP + ATP - r 421835 2.7.7.72 a tRNA with a 3' CCA end + 3 diphosphate - Homo sapiens a tRNA precursor + 2 CTP + ATP - r 421835 2.7.7.72 a tRNA with a 3' CCA end + 3 diphosphate substrate is synthetic DNA templates based on the sequence of Escherichia coli tRNAVal. Overall reaction, class II CCA-adding enzymes also perform the reverse reaction, mechanism, overview. The enzyme catalyzes diphosphorolysis slowly relative to the forward nucleotide addition and that it exhibits weak binding affinity to diphosphate relative to NTP Escherichia coli a tRNA precursor + 2 CTP + ATP - r 421835 2.7.7.72 a tRNA with a 3' CCA end + 3 diphosphate substrate is synthetic DNA templates based on the sequence of Escherichia coli tRNAVal. Overall reaction, class II CCA-adding enzymes also perform the reverse reaction, mechanism, overview. The enzyme catalyzes diphosphorolysis slowly relative to the forward nucleotide addition and that it exhibits weak binding affinity to diphosphate relative to NTP Homo sapiens a tRNA precursor + 2 CTP + ATP - r 421835 2.7.7.72 a tRNA with a 3' cytidine + CTP - Saccharolobus shibatae a tRNA with a 3' CC end + diphosphate - ? 422719 2.7.7.72 a tRNA with a 3' cytidine + CTP - Archaeoglobus fulgidus a tRNA with a 3' CC end + diphosphate - ? 422719 2.7.7.72 a tRNA with a 3' cytidine + CTP C75 addition Archaeoglobus fulgidus a tRNA with a 3' CC end + diphosphate - ? 422719 2.7.7.72 a tRNA with a 3' cytidine + CTP one catalytic center is responsible for addition of both CTP and ATP. As the single active site catalyzes addition of each nucleotide, the growing 3'-end of the tRNA would progressively refold to create a binding pocket for addition of the next nucleotide Saccharolobus shibatae a tRNA with a 3' CC end + diphosphate - ? 422719 2.7.7.72 a tRNA(Ala) precursor + 2 CTP + ATP synthesizes poly(C) when incubated with CTP alone, but switches to synthesize CCA when incubated with both CTP and ATP. The enzyme also exhibits a processing activity that removes nucleotides in the 3' to 5' direction to as far as position 74 Saccharolobus shibatae a tRNA(Ala) with a 3' CCA end + 3 diphosphate - ? 425863 2.7.7.72 armless tRNA(Arg) precursor + 2 CTP - Romanomermis culicivorax armless tRNA(Arg) with a 3' CC end + 2 diphosphate - ? 459193 2.7.7.72 armless tRNA(Arg) precursor + 2 CTP poor substrate for wild-type Homo sapiens armless tRNA(Arg) with a 3' CC end + 2 diphosphate - ? 459193 2.7.7.72 armless tRNA(Arg) precursor + 2 CTP + ATP - Romanomermis culicivorax armless tRNA(Arg) with a 3' CCA end + 3 diphosphate - ? 459192 2.7.7.72 armless tRNA(Arg) precursor + 2 CTP + ATP poor substrate for wild-type Homo sapiens armless tRNA(Arg) with a 3' CCA end + 3 diphosphate - ? 459192 2.7.7.72 armless tRNA(Ile) precursor + 2 CTP - Romanomermis culicivorax armless tRNA(Ile) with a 3' CC end + 2 diphosphate - ? 459195 2.7.7.72 armless tRNA(Ile) precursor + 2 CTP poor substrate for wild-type Homo sapiens armless tRNA(Ile) with a 3' CC end + 2 diphosphate - ? 459195 2.7.7.72 armless tRNA(Ile) precursor + 2 CTP + ATP - Romanomermis culicivorax armless tRNA(Ile) with a 3' CCA end + 3 diphosphate - ? 459194 2.7.7.72 armless tRNA(Ile) precursor + 2 CTP + ATP poor substrate for wild-type Homo sapiens armless tRNA(Ile) with a 3' CCA end + 3 diphosphate - ? 459194 2.7.7.72 ATP + tRNA-C-C - Geobacter sulfurreducens tRNA-C-C-A + diphosphate - ? 376366 2.7.7.72 ATP + tRNA-C-C - Alkalihalobacillus clausii tRNA-C-C-A + diphosphate - ? 376366 2.7.7.72 ATP + tRNA-C-C - Thermus thermophilus tRNA-C-C-A + diphosphate - ? 376366 2.7.7.72 CTP + tRNA-C - Geobacter sulfurreducens tRNA-C-C + diphosphate - ? 411905 2.7.7.72 deoxynucleoside triphosphate + DNAn the specific recognition of deaminated bases by polymerase PolB1 may represent an initial step in their repair while polymerase PolY1 may be involved in damage tolerance at the replication fork. The deaminated bases can be introduced into DNA enzymatically, since both PolB1 and PolY1 are able to incorporate the aberrant DNA precursors dUTP and dITP Saccharolobus solfataricus diphosphate + DNAn+1 - ? 358521 2.7.7.72 deoxynucleoside triphosphate + DNAn specifically recognizes the presence of the deaminated bases hypoxanthine and uracil in the template by stalling DNA polymerization 3-4 bases upstream of these lesions and strongly associates with oligonucleotides containing them. PolB1 also stops at 8-oxoguanine and is unable to bypass an abasic site in the template. The deaminated bases can be introduced into DNA enzymatically, since both PolB1 and PolY1 are able to incorporate the aberrant DNA precursors dUTP and dITP Saccharolobus solfataricus diphosphate + DNAn+1 - ? 358521 2.7.7.72 deoxynucleoside triphosphate + DNAn the specific recognition of deaminated bases by polymerase PolB1 may represent an initial step in their repair while polymerase PolY1 may be involved in damage tolerance at the replication fork. The deaminated bases can be introduced into DNA enzymatically, since both PolB1 and PolY1 are able to incorporate the aberrant DNA precursors dUTP and dITP Saccharolobus solfataricus P2 diphosphate + DNAn+1 - ? 358521 2.7.7.72 deoxynucleoside triphosphate + DNAn specifically recognizes the presence of the deaminated bases hypoxanthine and uracil in the template by stalling DNA polymerization 3-4 bases upstream of these lesions and strongly associates with oligonucleotides containing them. PolB1 also stops at 8-oxoguanine and is unable to bypass an abasic site in the template. The deaminated bases can be introduced into DNA enzymatically, since both PolB1 and PolY1 are able to incorporate the aberrant DNA precursors dUTP and dITP Saccharolobus solfataricus P2 diphosphate + DNAn+1 - ? 358521 2.7.7.72 additional information NTSFIII is inactive with CTP and tRNAAsp-C as substrates Geobacter sulfurreducens ? - ? 89 2.7.7.72 additional information the CCA-adding enzymes can use three different substrates: tRNAs lacking one, i.e. tRNA-CC, two, i.e. tRNA-C, or all three 3'-terminal nucleotides, tRNA. The CCA-adding enzyme recognizes primarily the top half tRNA minihelix Escherichia coli ? - ? 89 2.7.7.72 additional information the CCA-adding enzymes can use three different substrates: tRNAs lacking one, i.e. tRNA-CC, two, i.e. tRNA-C, or all three 3'-terminal nucleotides, tRNA. The Sulfolobus shibatae CCA-adding enzyme forms a stable complex with tRNA. The CCA-adding enzyme recognizes primarily the top half tRNA minihelix Saccharolobus shibatae ? - ? 89 2.7.7.72 additional information the enzyme catalyses a unique template-independent but sequence-specific nucleotide polymerization reaction, active site structure and molecular mechanism, overview. Construction of a corkscrew model for CCA addition that includes a fixed active site and a traveling tRNA-binding region formed by flexible parts of the protein Homo sapiens ? - ? 89 2.7.7.72 additional information the HD domain of the enzyme also exhibits 2',3'-cyclic phosphodiesterase, 2'-nucleotidase, and Ni2+-dependent phosphatase activities, overview Escherichia coli ? - ? 89 2.7.7.72 additional information the tRNA substrate must remain fixed on the enzyme surface during CA addition, tRNA-C cross-linked to the enzyme remains fully active for addition of CTP and ATP. The growing 3'-terminus of the tRNA progressively refolds to allow the solitary active site to reuse a single CTP binding site. The ATP binding site is then created collaboratively by the refolded CCterminus and the enzyme, and nucleotide addition ceases when the nucleotide binding pocket is full. The template for CCA addition is a dynamic ribonucleoprotein structure. Both CTP addition to tRNA-C and ATP addition to tRNA-CC are dramatically inhibited by alkylation of the same tRNA phosphates in the acceptor stem and TPsiC stem-loop Saccharolobus shibatae ? - ? 89 2.7.7.72 additional information the tRNA substrate must remain fixed on the enzyme surface during CA addition. Both CTP addition to tRNA-C and ATP addition to tRNA-CC are dramatically inhibited by alkylation of the same tRNA phosphates in the acceptor stem and TPsiC stem-loop Escherichia coli ? - ? 89 2.7.7.72 additional information CCA-adding enzymes recognize tRNA and tRNA-like structures as substrates, select and discriminate the correct nucleotides CTP and ATP against UTP and GTP, and, after incorporation of two C residues, the nucleotide specificity has to switch towards ATP without the help of a nucleic acid template. The enzymes have to stop polymerization exactly after three positions and recognize partial CCA-ends and add only the missing residues for completion, instead of stubbornly adding CCA-ends to their substrates, overview Thermus thermophilus ? - ? 89 2.7.7.72 additional information CCA-adding enzymes recognize tRNA and tRNA-like structures as substrates, select and discriminate the correct nucleotides CTP and ATP against UTP and GTP, and, after incorporation of two C residues, the nucleotide specificity has to switch towards ATP without the help of a nucleic acid template. The enzymes have to stop polymerization exactly after three positions and recognize partial CCA-ends and add only the missing residues for completion, instead of stubbornly adding CCA-ends to their substrates, overview Escherichia coli ? - ? 89 2.7.7.72 additional information CCA-adding enzymes recognize tRNA and tRNA-like structures as substrates, select and discriminate the correct nucleotides CTP and ATP against UTP and GTP, and, after incorporation of two C residues, the nucleotide specificity has to switch towards ATP without the help of a nucleic acid template. The enzymes have to stop polymerization exactly after three positions and recognize partial CCA-ends and add only the missing residues for completion, instead of stubbornly adding CCA-ends to their substrates, overview Homo sapiens ? - ? 89 2.7.7.72 additional information CCA-adding enzymes recognize tRNA and tRNA-like structures as substrates, select and discriminate the correct nucleotides CTP and ATP against UTP and GTP, and, after incorporation of two C residues, the nucleotide specificity has to switch towards ATP without the help of a nucleic acid template. The enzymes have to stop polymerization exactly after three positions and recognize partial CCA-ends and add only the missing residues for completion, instead of stubbornly adding CCA-ends to their substrates, overview Geobacillus stearothermophilus ? - ? 89 2.7.7.72 additional information CCA-adding enzymes recognize tRNA and tRNA-like structures as substrates, select and discriminate the correct nucleotides CTP and ATP against UTP and GTP, and, after incorporation of two C residues, the nucleotide specificity has to switch towards ATP without the help of a nucleic acid template. The enzymes have to stop polymerization exactly after three positions and recognize partial CCA-ends and add only the missing residues for completion, instead of stubbornly adding CCA-ends to their substrates, overview Saccharolobus shibatae ? - ? 89 2.7.7.72 additional information CCA-adding enzymes recognize tRNA and tRNA-like structures as substrates, select and discriminate the correct nucleotides CTP and ATP against UTP and GTP, and, after incorporation of two C residues, the nucleotide specificity has to switch towards ATP without the help of a nucleic acid template. The enzymes have to stop polymerization exactly after three positions and recognize partial CCA-ends and add only the missing residues for completion, instead of stubbornly adding CCA-ends to their substrates, overview Archaeoglobus fulgidus ? - ? 89 2.7.7.72 additional information CCA-adding enzymes recognize tRNA and tRNA-like structures as substrates, select and discriminate the correct nucleotides CTP and ATP against UTP and GTP, and, after incorporation of two C residues, the nucleotide specificity has to switch towards ATP without the help of a nucleic acid template. The enzymes have to stop polymerization exactly after three positions and recognize partial CCA-ends and add only the missing residues for completion, instead of stubbornly adding CCA-ends to their substrates, overview Thermotoga maritima ? - ? 89 2.7.7.72 additional information the specific enzyme incorporates only a highly restricted number of nucleotides in a tRNA primer and then stops polymerization at a high efficiency and accuracy. It selects exclusively CTP and ATP for incorporation and discriminates strongly against the other two nucleotide triphosphates. It does not require a nucleic acid template for directing order and nature of nucleotides to be inserted and is highly selective for tRNA-like structures as a polymerization substrate. The enzyme fulfills both functions in maintenance/repair as well as de novo polymerization Thermus thermophilus ? - ? 89 2.7.7.72 additional information the specific enzyme incorporates only a highly restricted number of nucleotides in a tRNA primer and then stops polymerization at a high efficiency and accuracy. It selects exclusively CTP and ATP for incorporation and discriminates strongly against the other two nucleotide triphosphates. It does not require a nucleic acid template for directing order and nature of nucleotides to be inserted and is highly selective for tRNA-like structures as a polymerization substrate. The enzyme fulfills both functions in maintenance/repair as well as de novo polymerization Escherichia coli ? - ? 89 2.7.7.72 additional information the specific enzyme incorporates only a highly restricted number of nucleotides in a tRNA primer and then stops polymerization at a high efficiency and accuracy. It selects exclusively CTP and ATP for incorporation and discriminates strongly against the other two nucleotide triphosphates. It does not require a nucleic acid template for directing order and nature of nucleotides to be inserted and is highly selective for tRNA-like structures as a polymerization substrate. The enzyme fulfills both functions in maintenance/repair as well as de novo polymerization Homo sapiens ? - ? 89 2.7.7.72 additional information the specific enzyme incorporates only a highly restricted number of nucleotides in a tRNA primer and then stops polymerization at a high efficiency and accuracy. It selects exclusively CTP and ATP for incorporation and discriminates strongly against the other two nucleotide triphosphates. It does not require a nucleic acid template for directing order and nature of nucleotides to be inserted and is highly selective for tRNA-like structures as a polymerization substrate. The enzyme fulfills both functions in maintenance/repair as well as de novo polymerization Archaea ? - ? 89 2.7.7.72 additional information the specific enzyme incorporates only a highly restricted number of nucleotides in a tRNA primer and then stops polymerization at a high efficiency and accuracy. It selects exclusively CTP and ATP for incorporation and discriminates strongly against the other two nucleotide triphosphates. It does not require a nucleic acid template for directing order and nature of nucleotides to be inserted and is highly selective for tRNA-like structures as a polymerization substrate. The enzyme fulfills both functions in maintenance/repair as well as de novo polymerization Deinococcus radiodurans ? - ? 89 2.7.7.72 additional information the specific enzyme incorporates only a highly restricted number of nucleotides in a tRNA primer and then stops polymerization at a high efficiency and accuracy. It selects exclusively CTP and ATP for incorporation and discriminates strongly against the other two nucleotide triphosphates. It does not require a nucleic acid template for directing order and nature of nucleotides to be inserted and is highly selective for tRNA-like structures as a polymerization substrate. The enzyme fulfills both functions in maintenance/repair as well as de novo polymerization Aquifex aeolicus ? - ? 89 2.7.7.72 additional information the specific enzyme incorporates only a highly restricted number of nucleotides in a tRNA primer and then stops polymerization at a high efficiency and accuracy. It selects exclusively CTP and ATP for incorporation and discriminates strongly against the other two nucleotide triphosphates. It does not require a nucleic acid template for directing order and nature of nucleotides to be inserted and is highly selective for tRNA-like structures as a polymerization substrate. The enzyme fulfills both functions in maintenance/repair as well as de novo polymerization Halalkalibacterium halodurans ? - ? 89 2.7.7.72 additional information the specific enzyme incorporates only a highly restricted number of nucleotides in a tRNA primer and then stops polymerization at a high efficiency and accuracy. It selects exclusively CTP and ATP for incorporation and discriminates strongly against the other two nucleotide triphosphates. It does not require a nucleic acid template for directing order and nature of nucleotides to be inserted and is highly selective for tRNA-like structures as a polymerization substrate. The enzyme fulfills both functions in maintenance/repair as well as de novo polymerization Caldanaerobacter subterraneus subsp. tengcongensis ? - ? 89 2.7.7.72 additional information class 1 enzymes recognize and select the correct nucleotides not as pure protein-based enzymes, but as ribonucleoproteins, where the tRNA part is not just a substrate molecule (primer), but is an active part of the nucleotide binding pocket Archaea ? - ? 89 2.7.7.72 additional information class 2 enzymes select the nucleotides to be incorporated by a true amino acid template that consists of the three highly conserved residues glutamic acid, aspartic acid and arginine (EDxxR). The arginine residue forms hydrogen bonds with ATP (1 bond) and CTP (2 bonds), assisted by aspartate that contributes one hydrogen bond Thermus thermophilus ? - ? 89 2.7.7.72 additional information class 2 enzymes select the nucleotides to be incorporated by a true amino acid template that consists of the three highly conserved residues glutamic acid, aspartic acid and arginine (EDxxR). The arginine residue forms hydrogen bonds with ATP (1 bond) and CTP (2 bonds), assisted by aspartate that contributes one hydrogen bond Escherichia coli ? - ? 89 2.7.7.72 additional information class 2 enzymes select the nucleotides to be incorporated by a true amino acid template that consists of the three highly conserved residues glutamic acid, aspartic acid and arginine (EDxxR). The arginine residue forms hydrogen bonds with ATP (1 bond) and CTP (2 bonds), assisted by aspartate that contributes one hydrogen bond Homo sapiens ? - ? 89 2.7.7.72 additional information class 2 enzymes select the nucleotides to be incorporated by a true amino acid template that consists of the three highly conserved residues glutamic acid, aspartic acid and arginine (EDxxR). The arginine residue forms hydrogen bonds with ATP (1 bond) and CTP (2 bonds), assisted by aspartate that contributes one hydrogen bond Deinococcus radiodurans ? - ? 89 2.7.7.72 additional information class 2 enzymes select the nucleotides to be incorporated by a true amino acid template that consists of the three highly conserved residues glutamic acid, aspartic acid and arginine (EDxxR). The arginine residue forms hydrogen bonds with ATP (1 bond) and CTP (2 bonds), assisted by aspartate that contributes one hydrogen bond Aquifex aeolicus ? - ? 89 2.7.7.72 additional information class 2 enzymes select the nucleotides to be incorporated by a true amino acid template that consists of the three highly conserved residues glutamic acid, aspartic acid and arginine (EDxxR). The arginine residue forms hydrogen bonds with ATP (1 bond) and CTP (2 bonds), assisted by aspartate that contributes one hydrogen bond Halalkalibacterium halodurans ? - ? 89 2.7.7.72 additional information class 2 enzymes select the nucleotides to be incorporated by a true amino acid template that consists of the three highly conserved residues glutamic acid, aspartic acid and arginine (EDxxR). The arginine residue forms hydrogen bonds with ATP (1 bond) and CTP (2 bonds), assisted by aspartate that contributes one hydrogen bond Caldanaerobacter subterraneus subsp. tengcongensis ? - ? 89 2.7.7.72 additional information class I CCA enzymes do not catalyze diphosphorolysis in contrast to class II CCA enzymes, overview Archaeoglobus fulgidus ? - ? 89 2.7.7.72 additional information only class II CCA enzymes catalyze diphosphorolysis, the reaction can initiate from all three CCA positions and proceed processively until the removal of nucleotide C74. Diphosphorolysis enables class II enzymes to efficiently remove an incorrect A75 nucleotide from the 3' end, at a rate much faster than the rate of A75 incorporation, suggesting the ability to perform a previously unexpected quality control mechanism for CCA synthesis. No activity with non-tRNA substrate BMVTLSTyr or U2 snRNA. The enzyme shows a robust activity with tRNA-A75, degrading it down to tRNA-A73 (by 50%) while showing a minor activity with tRNA-C76 (less than 5% substrate conversion) and no activity with tRNA-A74. The incorrect A75 is more readily removed than it is synthesized, suggesting a quality control mechanism that can improve the overall accuracy of CCA synthesis Homo sapiens ? - ? 89 2.7.7.72 additional information only class II CCA enzymes catalyze diphosphorolysis, the reaction can initiate from all three CCA positions and proceed processively until the removal of nucleotide C74. Diphosphorolysis enables class II enzymes to efficiently remove an incorrect A75 nucleotide from the 3' end, at a rate much faster than the rate of A75 incorporation, suggesting the ability to perform a previously unexpected quality control mechanism for CCA synthesis. No activity with non-tRNA substrate U2 snRNA, but EcCCA is active with non-tRNA substrate BMV TLSTyr and removes the terminalA nucleotide without proceeding further. The enzyme shows a robust activity with tRNA-A75, degrading it down to tRNA-A73 (by 50%) while showing a minor activity with tRNA-C76 (less than 5% substrate conversion) and no activity with tRNA-A74. The incorrect A75 is more readily removed than it is synthesized, suggesting a quality control mechanism that can improve the overall accuracy of CCA synthesis Escherichia coli ? - ? 89 2.7.7.72 additional information in Aquifex aeolicus, 3'-terminal CCA (CCA-3' at positions 74-76) of tRNA is synthesized by CC-adding and A-adding enzymes collaboratively. CC addition onto tRNA is catalyzed by poly A polymerase. After C74 addition in an enclosed active pocket and diphosphate release, the tRNA translocates and rotates relative to the enzyme, and C75 addition occurs in the same active pocket as C74 addition. At both the C74-adding and C75-adding stages, CTP is selected by Watson-Crick-like hydrogen bonds between the cytosine of CTP and conserved Asp and Arg residues in the pocket. After C74C75 addition and diphosphate release, the tRNA translocates further and drops off the enzyme Aquifex aeolicus ? - ? 89 2.7.7.72 additional information tRNA minihelices, which contain only the acceptor stem and TPsiC stem-loop, are also efficiently subjected to CCACCA addition when they have guanosines at the first and second positions as well as a destabilized acceptor stem by virtue of mismatches and G-U wobbles Archaeoglobus fulgidus ? - ? 89 2.7.7.72 additional information both isoforms Cca1 and Cca2 accept the complete sets of cytosolic and mitochondrial tRNAs at the individual developmental stages. Isoform Cca2 shows efficient binding to the substrates with a Kd of 2.3 microM and 1.7 microM for the in vitro transcript and the in vivo tRNA preparation, respectively. Isoform Cca1 shows almost no binding at any protein concentration Dictyostelium discoideum ? - - 89 2.7.7.72 additional information enzyme accepts normal tRNA precursors as well as mitochondrial miniaturized hairpin-like tRNA molecules that lack D- as well as T-arms Romanomermis culicivorax ? - - 89 2.7.7.72 tRNA(Leu) precursor + 2 CTP + ATP - Dictyostelium discoideum tRNA(Leu) with a 3'CCA end + 3 diphosphate - ? 459923 2.7.7.72 tRNA(Phe) precursor + 2 CTP - Homo sapiens tRNA(Phe) with a 3' CC end + 2 diphosphate - ? 459924 2.7.7.72 tRNA(Phe) precursor + 2 CTP - Romanomermis culicivorax tRNA(Phe) with a 3' CC end + 2 diphosphate - ? 459924 2.7.7.72 tRNA(Phe) precursor + 2 CTP + ATP - Homo sapiens tRNA(Phe) with a 3' CCA end + 3 diphosphate - ? 421592 2.7.7.72 tRNA(Phe) precursor + 2 CTP + ATP - Romanomermis culicivorax tRNA(Phe) with a 3' CCA end + 3 diphosphate - ? 421592 2.7.7.72 tRNA(Phe) precursor + 2 CTP + ATP the 48 kDa monomer forms a stable salt-resistant dimer in solution. Further dimerization of the dimeric enzyme to form a tetramer is induced by the binding of two tRNA molecules. The formation of a tetramer with only two bound tRNA molecules leads to the suggestion that one pair of active sites may be specific for adding two C bases, which results in scrunching of the primer strand. An adjacent second pair of active sites may be specific for adding A after addition of two C bases which makes the 30 terminus long enough to reach the second pair of active sites Saccharolobus shibatae tRNA(Phe) with a 3' CCA end + 3 diphosphate - ? 421592 2.7.7.72 tRNA(Phe) precursor + 2 CTP + ATP substrate is tRNA(Phe) precursor from Saccharomyces cerevisiae Bacillus subtilis tRNA(Phe) with a 3' CCA end + 3 diphosphate - ? 421592 2.7.7.72 tRNA(Phe) precursor + 2 CTP + ATP substrate is tRNA(Phe) precursor from Saccharomyces cerevisiae Exiguobacterium sibiricum tRNA(Phe) with a 3' CCA end + 3 diphosphate - ? 421592 2.7.7.72 tRNA(Phe) precursor + 2 CTP + ATP substrate is tRNA(Phe) precursor from Saccharomyces cerevisiae Geobacillus stearothermophilus tRNA(Phe) with a 3' CCA end + 3 diphosphate - ? 421592 2.7.7.72 tRNA(Phe) precursor + 2 CTP + ATP substrate is tRNA(Phe) precursor from Saccharomyces cerevisiae Planococcus halocryophilus tRNA(Phe) with a 3' CCA end + 3 diphosphate - ? 421592 2.7.7.72 tRNA(Phe) precursor + 2 CTP + ATP substrate is tRNA(Phe) precursor from Saccharomyces cerevisiae Bacillus subtilis 168 tRNA(Phe) with a 3' CCA end + 3 diphosphate - ? 421592 2.7.7.72 tRNA(Phe) precursor + 2 CTP + ATP substrate is tRNA(Phe) precursor from Saccharomyces cerevisiae Exiguobacterium sibiricum DSM 17290 tRNA(Phe) with a 3' CCA end + 3 diphosphate - ? 421592 2.7.7.72 tRNA(Ser) precursor + 2 CTP + ATP - Dictyostelium discoideum tRNA(Ser) with a 3'CCA end + 3 diphosphate - ? 459925 2.7.7.72 tRNAAsp with a 3' CC end + ATP usage of tRNAAsp of Bacillus subtilis as substrate, and 5'-labeled tRNA-C and 3'-labeled tRNA-CC alkylated by ethylnitrosourea Escherichia coli tRNAAsp with a 3' CCA end + diphosphate - ? 419153 2.7.7.72 tRNAAsp with a 3' CC end + ATP usage of tRNAAsp of Bacillus subtilis as substrate, and 5'-labeled tRNA-C and 3'-labeled tRNA-CC alkylated by ethylnitrosourea Saccharolobus shibatae tRNAAsp with a 3' CCA end + diphosphate - ? 419153 2.7.7.72 tRNAAsp with a 3' cytidine + CTP usage of tRNAAsp of Bacillus subtilis as substrate, and 5'-labeled tRNA-C and 3'-labeled tRNA-CC alkylated by ethylnitrosourea Escherichia coli tRNAAsp with a 3' CC end + diphosphate - ? 419154 2.7.7.72 tRNAAsp with a 3' cytidine + CTP usage of tRNAAsp of Bacillus subtilis as substrate, and 5'-labeled tRNA-C and 3'-labeled tRNA-CC alkylated by ethylnitrosourea Saccharolobus shibatae tRNAAsp with a 3' CC end + diphosphate - ? 419154 2.7.7.72 tRNACys + 2 CTP + ATP insertional editing of substrate is not required for addition of the CCA sequence by CCase Bacillus subtilis tRNACys with 3'-CCA end + 3 diphosphate - ? 413005 2.7.7.72 tRNAHis+G-1 + 2 CTP + ATP - Saccharomyces cerevisiae tRNAHis+G-1 with a 3' CCA end + 3 diphosphate - ? 459926 2.7.7.72 tRNAHis+G-1 + 2 CTP + ATP - Saccharomyces cerevisiae ATCC 204508 tRNAHis+G-1 with a 3' CCA end + 3 diphosphate - ? 459926 2.7.7.72 tRNAHisDELTAG-1 + 2 CTP + ATP - Saccharomyces cerevisiae tRNAHisDELTAG-1 with a 3' CCA end + 3 diphosphate - ? 459927 2.7.7.72 tRNAHisDELTAG-1 + 2 CTP + ATP - Saccharomyces cerevisiae ATCC 204508 tRNAHisDELTAG-1 with a 3' CCA end + 3 diphosphate - ? 459927 2.7.7.72 tRNAX1 + ATP + 2 CTP only one protein is responsible for both AMP and CMP incorporation Escherichia coli tRNAXCCA + 3 diphosphate - r 419155 2.7.7.72 tRNAX1 + ATP + 2 CTP only one protein is responsible for both AMP and CMP incorporation Escherichia coli B / ATCC 11303 tRNAXCCA + 3 diphosphate - r 419155 2.7.7.72 yeast tRNAPhe + 2 CTP + ATP preparation of substrate lacking the CCA-terminus or ending with a partial CCA-end Escherichia coli yeast tRNAPhe with 3'-CCA end + 3 diphosphate - ? 413079 2.7.7.72 yeast tRNAPhe + 2 CTP + ATP preparation of substrate lacking the CCA-terminus or ending with a partial CCA-end Geobacillus stearothermophilus yeast tRNAPhe with 3'-CCA end + 3 diphosphate - ? 413079 2.7.7.72 yeast tRNAPhe + 2 CTP + ATP preparation of substrate lacking the CCA-terminus or ending with a partial CCA-end Homo sapiens yeast tRNAPhe with 3'-CCA end + 3 diphosphate - ? 413079