PDBsum entry 1h9l

Hydrolase/hydrolase inhibitor

PDB id: 1h9l

Contents

Protein chain

240 a.a. *

Ligands

VAL-GLU-PRO-ILE

SO4

Metals

_CA

Waters ×233

* Residue conservation analysis

PDB id:

1h9l

Name:

Hydrolase/hydrolase inhibitor

Title:

Porcine pancreatic elastase complexed with acetyl-val-glu-pro-ile-cooh

Structure:

Peptide inhibitor. Chain: a. Engineered: yes. Elastase. Chain: b. Synonym: ppe. Ec: 3.4.21.36

Source:

Synthetic: yes. Synthetic construct. Organism_taxid: 32630. Sus scrofa. Pig. Organism_taxid: 9823. Organ: pancreas

Biol. unit:

Dimer (from PQS)

Resolution:

1.67Å R-factor: 0.159 R-free: 0.199

Authors:

P.A.Wright,R.C.Wilmouth,I.J.Clifton,C.J.Schofield

Key ref:

P.A.Wright et al. (2001). Kinetic and crystallographic analysis of complexes formed between elastase and peptides from beta-casein. Eur J Biochem, 268, 2969-2974. PubMed id: 11358514 DOI: 10.1046/j.1432-1327.2001.02186.x

Date:

13-Mar-01 Release date: 27-Nov-01

Protein chain

P00772  (CELA1_PIG) -  Chymotrypsin-like elastase family member 1 from Sus scrofa

Seq: 266 a.a.

Struc: 240 a.a.*

* PDB and UniProt seqs differ at 1 residue position (black cross)

Enzyme reactions

• Enzyme class: E.C.3.4.21.36 - pancreatic elastase.
• Reaction: Hydrolysis of proteins, including elastin. Preferential cleavage: Ala-|-Xaa.

DOI no: 10.1046/j.1432-1327.2001.02186.x

Eur J Biochem 268:2969-2974 (2001)

PubMed id: 11358514

Kinetic and crystallographic analysis of complexes formed between elastase and peptides from beta-casein.

P.A.Wright, R.C.Wilmouth, I.J.Clifton, C.J.Schofield.

ABSTRACT

Human beta-casomorphin-7 (NH2-Tyr-Pro-Phe-Val-Glu-Pro-Ile-CO2H) is a naturally occurring peptide inhibitor of elastase that has been shown to form an acyl-enzyme complex stable enough for X-ray crystallographic analysis at pH 5. To investigate the importance of the N-terminal residues of the beta-casomorphin-7 peptide for the inhibition of elastase, kinetic and crystallographic analyses were undertaken to identify the minimum number of residues required for effective formation of a stable complex between truncated beta-casomorphin-7 peptides and porcine pancreatic elastase (PPE). The results clearly demonstrate that significant inhibition of PPE can be effected by simple tri-, tetra-and pentapeptides terminating in a carboxylic acid. These results also suggest that in vivo regulation of protease activity could be mediated via short peptides as well as by proteins. Crystallographic analysis of the complex formed between N-acetyl-Val-Glu-Pro-Ile-CO2H and PPE at pH 5 (to 1.67 A resolution) revealed an active site water molecule in an analogous position to that observed in the PPE/beta-casomorphin-7 structure supportive of its assignment as the 'hydrolytic water' in the deacylation step of serine protease catalysis.

Selected figure(s)

Figure 1.
Fig. 1. Schematic diagram showing the antiparallel sheet formed between a productively bound peptide and the active site of PPE. The nomenclature for the residues of the peptide (P[1]–P[4]) and their respective subsites in the active site (S[1]–S[4]) is also shown.

Figure 2.
Fig. 2. Stereo-views of the acyl-enzyme complex formed between N-acetyl-Val-Glu-Pro-Ile-CO[2]H (in gold) and PPE (in green). The peptide is linked via an ester bond between its C-terminal isoleucine and Ser195 of PPE. (A) Location of the proposed hydrolytic water molecule (Wat532) hydrogen bonded to N[ 2] of His57 and poised for nucleophilic attack above the ester carbonyl. (B) Antiparallel sheet formed between N-acetyl-Val-Glu-Pro-Ile-CO[2]H and the Ser214–Val216 loop in the active site of PPE. The 2mF[o]DF[c] electron density maps [26] were contoured at 1 . This figure was produced using BOBSCRIPT [27], RASTER3D [28], IMAGEMAGICK and PHOTOSHOP 5.0 (Adobe Systems Inc.).

The above figures are reprinted by permission from the Federation of European Biochemical Societies: Eur J Biochem (2001, 268, 2969-2974) copyright 2001.