EC Number   |
General Information |
Reference |
|---|
   6.2.1.55 | evolution |
ancestral relatives of Ub/E1 are identified that mobilize sulfur to form sulfur-containing biomolecules (e.g. thiamine, molybdopterin (MPT), thiolated tRNA, thiol-functionalized siderophores, and 2-thiosugars). In bacteria, these E1-like enzymes adenylate and activate the C-terminus of the Ub-like (Ubl) protein by hydrolyzing ATP and releasing diphosphate. Comparison of E1/MoeB/ThiF superfamily proteins. UbaA contains no rhodaneses (RHD) domain |
-, 744867 |
| 6.2.1.55 | malfunction |
no samp3ylation is detected in the DELTAubaA mutant |
-, 730386 |
| 6.2.1.55 | malfunction |
the ubaA mutant is deficient in SAMPylation with unconjugated Flag-SAMP1 and Flag-SAMP2 proteins. The ubaA knockout is complemented by providing a wild-type copy, but not a C188S variant of ubaA in trans. The ubaA mutant is retarded in growth at 50°C |
-, 730808 |
| 6.2.1.55 | more |
key residues within the adenylation domain of UbaA are needed to bind ATP, discovery of residues that are specifically needed to catalyze the downstream reactions of sulfur mobilization and/or Ubl protein modification, overview. The enzyme has an active site cysteine residue, Cys188, that is critical for the sulfurtransferase activity, but not needed to form the thiol-intermediate or Ubl-bonds, also residue K159 is not required for ubiquitin-like bond formation. Residues C171 and C245 of the Cys tetrade and residues K87 and D131 are all required for all enzyme activities, while C174 and C248 are not essential, Residue C265 is needed for the thiolation of wobble uridine tRNA. Residue R74 is not critical for the sulfurtransferase activity, but needed to form Ubl-bonds. Residue N71 is required for thiolation of tRNA, sulfurtransferase, and Ubl bond formation activities. Residues K87 and K157 are autosampylated |
-, 744867 |
| 6.2.1.55 | more |
the crystal structure of SAMP1, PDB ID 3PO0, is docked to the three-dimensional model of UbaA using the Escherichia coli MoaD-MoeB complex as a template, PDB ID 1JW9. Enzyme UbaA dimeric complex structure modeling, and ab initio modeling of the remaining 25 residues of UbaA, which include the highly disordered N- and C-termini |
-, 746408 |
| 6.2.1.55 | physiological function |
in bacteria, these E1-like enzymes adenylate and activate the C-terminus of the Ub-like (Ubl) protein by hydrolyzing ATP and releasing diphosphate. Protein modification and sulfur mobilization activities of noncanonical E1 and associated ubiquitin-like (Ubl) proteins of archaea, overview. Enzyme UbaA is autoregulated by Ubl-protein modification and structurally flexible to allow Ubl-adenylate, Ubl-E1 thioester and persulfide(s) intermediates to form in the absence of a canonical E1 active site cysteine. Autosampylation of K87 and K157 likely regulates UbaA function |
-, 744867 |
| 6.2.1.55 | physiological function |
the archaeon Haloferax volcanii uses SAMP1 as a protein modifier to regulate and orchestrate cellular functions. SAMP1 is ligated to proteins by transfer via SAMP-activating E1 enzyme UbaA, i.e. samp1ylation. SAMP1 is a ubiquitin-like protein modifier that is relatively specific in tagging its protein partners as well as proteins associated with oxidative stress response. SAMP1 modifies a relatively small number of protein targets. SAMPs are activated (adenylated) in an ATP-dependent manner by the E1-like UbaA/ELSA and liberated from SAMP conjugates by the action of the JAMM/MPN+ Zn2+-metalloprotease HvJAMM1. SAMP1 conjugation is speculated to regulate the catalytic activity of MPT synthase, the conserved K240 and K247 residues of MoaE, the large subunit of MPT synthase, are found to be covalently attached to C-terminus of SAMP1 |
-, 746408 |
| 6.2.1.55 | physiological function |
the enzyme is required for the formation of both SAMP1- and SAMP2-protein conjugates. The enzyme can activate multiple ubiquitin-like proteins (SAMP1 and SAMP2) for protein conjugation as well as for sulfur transfer. In sulfur transfer, SAMP1 and SAMP2 appear specific for MoCo biosynthesis and the thiolation of tRNA, respectively |
-, 730808 |
| 6.2.1.55 | physiological function |
the novel small archaeal modifier protein (SAMP3) with a beta-grasp fold and C-terminal diglycine motif characteristic of ubiquitin is functional in protein conjugation in Haloferax volcanii. Archaeal ubiquitin-like SAMP3 is isopeptide-linked to proteins via a UbaA-dependent mechanism. SAMP3 conjugates are dependent on the ubiquitin-activating E1 enzyme homologue of archaea (UbaA) for synthesis and are cleaved by the JAMM/MPN+ domain metalloprotease HvJAMM1. Samp3ylation is covalent and reversible and controls the activity of enzymes such as MPT synthase. Sampylation of MPT synthase may govern the levels of molybdenum cofactor available and thus facilitate the scavenging of oxygen prior to the transition to respiration with molybdenum-cofactor-containing terminal reductases that use alternative electron acceptors such as dimethyl sulfoxide |
-, 745772 |
