Protein Variants | Comment | Organism |
---|---|---|
E166A | site-directed mutagenesis, inactive mutant. The Glu166Ala mutant form of BlaC has no hydrolytic activity and forms a stable acyl-enzyme complex that can be structurally characterized, suggesting that Glu166 is required for deacylation and product release | Mycobacterium tuberculosis |
K73A | site-directed mutagenesis, inactive mutant. The Lys73Ala mutant form of BlaC permits the structural identification of the Michaelis complex, but has no catalytic activity, indicating Lys73 is essential for the acylation step | Mycobacterium tuberculosis |
Inhibitors | Comment | Organism | Structure |
---|---|---|---|
clavulanate | - |
Mycobacterium tuberculosis |
KM Value [mM] | KM Value Maximum [mM] | Substrate | Comment | Organism | Structure |
---|---|---|---|---|---|
additional information | - |
additional information | pre-steady-state, stopped-flow experiments with cefoxitin, solvent kinetic isotope effects and kinetic analysis with different substrates, kinetic mechanism, overview | Mycobacterium tuberculosis |
Organism | UniProt | Comment | Textmining |
---|---|---|---|
Mycobacterium tuberculosis | P9WKD3 | gene blaC | - |
Mycobacterium tuberculosis H37Rv | P9WKD3 | gene blaC | - |
Substrates | Comment Substrates | Organism | Products | Comment (Products) | Rev. | Reac. |
---|---|---|---|---|---|---|
cefoxitin + H2O | high activity | Mycobacterium tuberculosis | (2R)-5-[(carbamoyloxy)methyl]-2-[(S)-carboxy(methoxy)[2-(thiophen-2-yl)acetamido]methyl]-3,6-dihydro-2H-1,3-thiazine-4-carboxylic acid | - |
? | |
cefoxitin + H2O | high activity | Mycobacterium tuberculosis H37Rv | (2R)-5-[(carbamoyloxy)methyl]-2-[(S)-carboxy(methoxy)[2-(thiophen-2-yl)acetamido]methyl]-3,6-dihydro-2H-1,3-thiazine-4-carboxylic acid | - |
? | |
doripenem + H2O | very low activity | Mycobacterium tuberculosis | (4R,5S)-5-[(1S,2R)-1-carboxy-2-hydroxypropyl]-4-methyl-3-([(3S,5S)-5-[(sulfamoylamino)methyl]pyrrolidin-3-yl]sulfanyl)-4,5-dihydro-1H-pyrrole-2-carboxylic acid | - |
? | |
doripenem + H2O | very low activity | Mycobacterium tuberculosis H37Rv | (4R,5S)-5-[(1S,2R)-1-carboxy-2-hydroxypropyl]-4-methyl-3-([(3S,5S)-5-[(sulfamoylamino)methyl]pyrrolidin-3-yl]sulfanyl)-4,5-dihydro-1H-pyrrole-2-carboxylic acid | - |
? | |
ertapenem + H2O | very low activity | Mycobacterium tuberculosis | (4R,5S)-5-[(1S,2R)-1-carboxy-2-hydroxypropyl]-3-([(3S,5S)-5-[(3-carboxyphenyl)carbamoyl]pyrrolidin-3-yl]sulfanyl)-4-methyl-4,5-dihydro-1H-pyrrole-2-carboxylic acid | - |
? | |
ertapenem + H2O | very low activity | Mycobacterium tuberculosis H37Rv | (4R,5S)-5-[(1S,2R)-1-carboxy-2-hydroxypropyl]-3-([(3S,5S)-5-[(3-carboxyphenyl)carbamoyl]pyrrolidin-3-yl]sulfanyl)-4-methyl-4,5-dihydro-1H-pyrrole-2-carboxylic acid | - |
? | |
meropenem + H2O | very slow substrate and low activity | Mycobacterium tuberculosis | (4R,5S)-5-[(1S,2R)-1-carboxy-2-hydroxypropyl]-3-[[(3S,5S)-5-(dimethylcarbamoyl)pyrrolidin-3-yl]sulfanyl]-4-methyl-4,5-dihydro-1H-pyrrole-2-carboxylic acid | - |
? | |
meropenem + H2O | very slow substrate and low activity | Mycobacterium tuberculosis H37Rv | (4R,5S)-5-[(1S,2R)-1-carboxy-2-hydroxypropyl]-3-[[(3S,5S)-5-(dimethylcarbamoyl)pyrrolidin-3-yl]sulfanyl]-4-methyl-4,5-dihydro-1H-pyrrole-2-carboxylic acid | - |
? | |
additional information | during the acylation reaction of carbapenems catalyzed by BlaC, the ring opening of the beta-lactam yields an initial DELTA2-pyrroline ring, which subsequently isomerizes to a DELTA1-pyrroline ring with stereospecific protonation at C3 to generate the final, stable acylated adduct | Mycobacterium tuberculosis | ? | - |
? | |
additional information | during the acylation reaction of carbapenems catalyzed by BlaC, the ring opening of the beta-lactam yields an initial DELTA2-pyrroline ring, which subsequently isomerizes to a DELTA1-pyrroline ring with stereospecific protonation at C3 to generate the final, stable acylated adduct | Mycobacterium tuberculosis H37Rv | ? | - |
? | |
nitrocefin + H2O | high activity | Mycobacterium tuberculosis | (2R)-2-[(R)-carboxy[2-(thiophen-2-yl)acetamido]methyl]-5-[(E)-2-(2,4-dinitrophenyl)ethenyl]-3,6-dihydro-2H-1,3-thiazine-4-carboxylic acid | - |
? |
Synonyms | Comment | Organism |
---|---|---|
BlaC | - |
Mycobacterium tuberculosis |
Temperature Optimum [°C] | Temperature Optimum Maximum [°C] | Comment | Organism |
---|---|---|---|
25 | - |
assay at | Mycobacterium tuberculosis |
pH Optimum Minimum | pH Optimum Maximum | Comment | Organism |
---|---|---|---|
7.8 | 8 | - |
Mycobacterium tuberculosis |
pH Minimum | pH Maximum | Comment | Organism |
---|---|---|---|
additional information | - |
pH dependence of the kinetic parameters, revealing that the maximum velocity depends on the ionization state of two groups: a general base exhibiting a pK value of 4.5 and a general acid exhibiting a pK value of 7.8, overview | Mycobacterium tuberculosis |
General Information | Comment | Organism |
---|---|---|
evolution | BlaC is a class A beta-lactamase | Mycobacterium tuberculosis |
additional information | the catalytic mechanism of BlaC relies on three highly conserved active site residues, Lys73 and Glu166, which are involved in the activation of the acylating nucleophile Ser70 and the activation of the active site water molecule for deacylation, respectively. Lys73 is essential for the acylation step | Mycobacterium tuberculosis |
physiological function | the constitutively expressed, chromosomally-encoded beta-lactamase (BlaC) is the enzyme responsible for the intrinsic resistance to beta-lactam antibiotics in Mycobacterium tuberculosis | Mycobacterium tuberculosis |