Overview for MACiE Entry M0288
EC Number: 18.104.22.168 (A member of the Hydrolases, Acting on carbon-nitrogen bonds, other than peptide bonds, In linear amides)
Enzyme Name: glutaryl-7-aminocephalosporanic-acid acylase
Biological Species: Pseudomonas sp. (Baceria)
Catalytic Chain UniprotKB Accession Codes:
- P07662 - Glutaryl-7-aminocephalosporanic-acid acylase subunit beta
Representative PDB Code: 3s8r - CRYSTAL STRUCTURES OF GLUTARYL 7-AMINOCEPHALOSPORANIC ACID ACYLASE:INSIGHT INTO AUTOPROTEOLYTIC ACTIVATION (Resolution = 2.50 Å).
Catalytic CATH Codes:
Display structure information
Overall Comment: In order for the enzyme to be activated towards catalysing the hydrolysis of the glutaryl form of 7-aminocephalosporanic acid, autoproteolysis must occur at the nucleophilic Ser170, revealing an N terminal nucleophile capable of inducing nucleophilic attack at the substrate's glutaryl carbonyl. The process forms two descrete proteins chains. The crystal structure depicts the non-cleaved, precursor protein, whereas the active protein froms a heterotetramer from the two resulting chains.
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Stepwise Description of the Reaction
|Step 1||A water molecule acts as a proton carrier in the deprotonation of the Ser170A side chain hydroxyl by the N terminal amine group.|
|Step 2||The side chain hydroxide of Ser170A attacks the substrate amide carbonyl, forming a tetrahedral intermediate.|
|Step 3||The tetrahedral intermediate collapses, forming a serine linked glutarate intermediate and eliminating 7-Aminocephalosporanic acid.|
|Step 4||The structurally conserved water molecule is activated by the non-protonated terminal amine of Ser170 to attack at the enzyme-substrate intermediate's carbonyl group, forming a second tetrahedral intermediate.|
|Step 5||The tetrahedral anion intermediate collapses, releasing glutarate and the N terminal serine.|
|Step 6||The anionic serine side chain undergoes an intamolecular deprotonation, removing a proton from the terminal amine group via a conserved water molecule.|
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Catalytic Residues Involved
||Location of Function
||Main Chain Amide
Main Chain N Terminus
- J. K. Kim et al. (2003), Biochemistry, 42, 4084-4093. Crystal structures of glutaryl 7-aminocephalosporanic acid acylase: insight into autoproteolytic activation.
- K. Fritz-Wolf et al. (2002), Protein Sci., 11, 92-103. Structure-based prediction of modifications in glutarylamidase to allow single-step enzymatic production of 7-aminocephalosporanic acid from cephalosporin C.
Homologue information for M0288 (3s8r)
MACiE Homologues (within the PDB)
MACiE Homologues (within UniprotKB/SwissProt)
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