Astacin

 

Astacin, a digestive zinc-endopeptidase from the crayfish Astacus astacus, is the prototype for the 'astacin family', which includes mammalian metallo-endopeptidases and developmentally regulated proteins of human, fruit fly, frog and sea urchin, and also for the 'metzincin superfamily'.

This protease prefers to cleave in front of small aliphatic residues (P1'). The presence of Lys or Arg in the P1 and P2 position yields high-turnover substrates. In the P3 position the enzyme prefers Pro > Val > Leu > Ala > Gly.

 

Reference Protein and Structure

Sequence
P07584 UniProt (3.4.24.21) IPR024079 (Sequence Homologues) (PDB Homologues)
Biological species
Astacus astacus (Broad-fingered crayfish) Uniprot
PDB
1ast - STRUCTURE OF ASTACIN AND IMPLICATIONS FOR ACTIVATION OF ASTACINS AND ZINC-LIGATION OF COLLAGENASES (1.8 Å) PDBe PDBsum 1ast
Catalytic CATH Domains
3.40.390.10 CATHdb (see all for 1ast)
Cofactors
Zinc(2+) (1)
Click To Show Structure

Enzyme Reaction (EC:3.4.24.21)

Ala-Pro
CHEBI:73393ChEBI
+
water
CHEBI:15377ChEBI
→
L-alanine
CHEBI:16977ChEBI
+
L-proline
CHEBI:17203ChEBI
Alternative enzyme names: Astacus proteinase, Crayfish small-molecule proteinase,

Enzyme Mechanism

Introduction

A zinc-activated water molecule is deprotonated by glutamate, and then carries out a nucleophilic attack on the substrate. A tyrosine residue stabilises the transition state.

Catalytic Residues Roles

UniProt PDB* (1ast)
His141, His151, His145 His92A, His102A, His96A Forms the zinc binding site. metal ligand
Tyr198 Tyr149A Stabilises the transition state. transition state stabiliser
Glu142 Glu93A Deprotonates the catalytic water molecule, protonates the amide leaving group. proton shuttle (general acid/base)
*PDB label guide - RESx(y)B(C) - RES: Residue Name; x: Residue ID in PDB file; y: Residue ID in PDB sequence if different from PDB file; B: PDB Chain; C: Biological Assembly Chain if different from PDB. If label is "Not Found" it means this residue is not found in the reference PDB.

Chemical Components

References

  1. Guevara T et al. (2010), J Biol Chem, 285, 13958-13965. Proenzyme Structure and Activation of Astacin Metallopeptidase. DOI:10.1074/jbc.m109.097436. PMID:20202938.
  2. Yiallouros I et al. (2000), FEBS Lett, 484, 224-228. The roles of Glu93 and Tyr149 in astacin-like zinc peptidases. DOI:10.1016/s0014-5793(00)02163-3. PMID:11078883.
  3. Grams F et al. (1996), Nat Struct Biol, 3, 671-675. Structure of astacin with a transition-state analogue inhibitor. PMID:8756323.
  4. Rawlings ND et al. (1995), Methods Enzymol, 248, 183-228. [13] Evolutionary families of metallopeptidases. DOI:10.1016/0076-6879(95)48015-3. PMID:7674922.
  5. Bode W et al. (1992), Nature, 358, 164-167. Structure of astacin and implications for activation of astacins and zinc-ligation of collagenases. DOI:10.1038/358164a0. PMID:1319561.
  6. Stöcker W et al. (1990), Biochemistry, 29, 10418-10425. Fluorescent oligopeptide substrates for kinetic characterization of the specificity of Astacus protease. PMID:2261483.

Step 1.

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Catalytic Residues Roles

Residue Roles
Glu93A proton shuttle (general acid/base)
Tyr149A transition state stabiliser
His92A metal ligand
His96A metal ligand
His102A metal ligand

Chemical Components

Step 1.

Contributors

Stuart Lucas, Craig Porter, Gemma L. Holliday