Overview for MACiE Entry M0241
EC Number: 22.214.171.124 (A member of the Hydrolases, Acting on carbon-nitrogen bonds, other than peptide bonds, In linear amides)
Enzyme Name: penicillin amidase
Biological Species: Bacillus sphaericus (Bacteria)
Catalytic Chain UniprotKB Accession Codes:
Representative PDB Code: 3pva - PENICILLIN V ACYLASE FROM B. SPHAERICUS (Resolution = 2.80 Å).
Catalytic CATH Codes:
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Overall Comment: This enzyme undergoes post-translational autocatalytic cleavage to produce the mature enzyme. A tripeptide of Met-Leu-Gly is removed to expose the catalytic N-terminal residue.
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Stepwise Description of the Reaction
|Step 1||The alpha-amine of Cys1 deprotonates the thiol group. The resulting thiolate is the nucleophile for attack on the carbonyl carbon. The tetrahedral intermediate is stabilised by the oxyanion hole.|
|Step 2||The tetrahedral intermediate collapses and eliminates 6-aminopenicillanate, with proton transfer from the alpha amine to the leaving group.|
|Step 3||The alpha amine deprotonates water, which then acts as the nucleophile for attack on the carbonyl carbon. The tetrahedral intermediate is stabilised by the oxyanion hole.|
|Step 4||The tetrahedral intermediate collapses and eliminates Cys1 phenoxyacetate. The Cys1 thiolate is protonated by the alpha amine.|
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Catalytic Residues Involved
||Location of Function
||Main Chain N Terminus
||Main Chain Amide
- M. Morillas et al. (1999), Biochem. J., 338, 235-239. The kinetics of acylation and deacylation of penicillin acylase from Escherichia coli ATCC 11105: evidence for lowered pKa values of groups near the catalytic centre.
- C. E. McVey et al. (2001), J. Mol. Biol., 313, 139-150. Crystal structures of penicillin acylase enzyme-substrate complexes: structural insights into the catalytic mechanism.
- H. J. Duggleby et al. (1955), Nature, 373, 264-268. Penicillin acylase has a single-amino-acid catalytic centre.
- J. A. Brannigan et al. (1995), Nature, 378, 416-419. A protein catalytic framework with an N-terminal nucleophile is capable of self-activation.
- P. Rathinaswamy et al. (2005), Acta Crystallogr Sect F Struct Biol Cryst Commun, 61, 680-683. Cloning, purification, crystallization and preliminary structural studies of penicillin V acylase from Bacillus subtilis.
- C. G. Suresh et al. (1999), Nat. Struct. Biol., 6, 414-416. Penicillin V acylase crystal structure reveals new Ntn-hydrolase family members.
Homologue information for M0241 (3pva)
MACiE Homologues (within the PDB)
MACiE Homologues (within UniprotKB/SwissProt)
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