PDBsum entry 1k9b

Hydrolase inhibitor

PDB id: 1k9b

Contents

Protein chain

58 a.a. *

Waters ×17

* Residue conservation analysis

PDB id:

1k9b

Name:

Hydrolase inhibitor

Title:

Crystal structure of the bifunctional soybean bowman-birk inhibitor at 0.28 nm resolution. Structural peculiarities in a folded protein conformation

Structure:

Bowman-birk type proteinase inhibitor. Chain: a. Synonym: bbi. Other_details: free form

Source:

Glycine max. Soybean. Organism_taxid: 3847

Biol. unit:

Hexamer (from PQS)

Resolution:

2.80Å R-factor: 0.221 R-free: 0.308

Authors:

R.H.Voss,U.Ermler,L.O.Essen,G.Wenzl,Y.M.Kim,P.Flecker

Key ref:

R.H.Voss et al. (1996). Crystal structure of the bifunctional soybean Bowman-Birk inhibitor at 0.28-nm resolution. Structural peculiarities in a folded protein conformation. Eur J Biochem, 242, 122-131. PubMed id: 8954162

Date:

29-Oct-01 Release date: 16-Nov-01

Protein chain

P01055  (IBB1_SOYBN) -  Bowman-Birk type proteinase inhibitor from Glycine max

Seq: 110 a.a.

Struc: 58 a.a.

Eur J Biochem 242:122-131 (1996)

PubMed id: 8954162

Crystal structure of the bifunctional soybean Bowman-Birk inhibitor at 0.28-nm resolution. Structural peculiarities in a folded protein conformation.

R.H.Voss, U.Ermler, L.O.Essen, G.Wenzl, Y.M.Kim, P.Flecker.

ABSTRACT

The Bowman-Birk inhibitor from soybean is a small protein that contains a binary arrangement of trypsin-reactive and chymotrypsin-reactive subdomains. In this report, the crystal structure of this anticarcinogenic protein has been determined to 0.28-nm resolution by molecular replacement from crystals grown at neutral pH. The crystal structure differs from a previously determined NMR structure [Werner, M. H. & Wemmer, D. E. (1992) Biochemistry 31, 999-1010] in the relative orientation of the two enzyme-insertion loops, in some details of the main chain trace, in the presence of favourable contacts in the trypsin-insertion loop, and in the orientation of several amino acid side chains. The proximity of Met27 and Gln48 in the X-ray structure contradicts the solution structure, in which these two side chains point away from each other. The significant effect of a Met27-->Ile replacement on the inhibitory activity of the chymotrypsin-reactive subdomain agrees with the X-ray structure. Exposed hydrophobic patches, the presence of charged amino acid residues, and the presence of water molecules in the protein interior are in contrast to standard proteins that comprise a hydrophobic core and exposed polar amino acids.