PDBsum entry 4zot

Protein binding

PDB id: 4zot

Contents

Protein chain

163 a.a.

Waters ×213

PDB id:

4zot

Name:

Protein binding

Title:

Crystal structure of bbki, a disulfide-free plasma kallikrein inhibitor at 1.4 a resolution

Structure:

Kunitz-type serine protease inhibitor bbki. Chain: a. Engineered: yes

Source:

Bauhinia bauhinioides. Organism_taxid: 166014. Expressed in: escherichia coli. Expression_system_taxid: 469008.

Resolution:

1.40Å R-factor: 0.125 R-free: 0.167

Authors:

I.G.Shabalin,D.Zhou,A.Wlodawer,M.L.V.Oliva

Key ref:

D.Zhou et al. (2015). Structure of BbKI, a disulfide-free plasma kallikrein inhibitor. Acta Crystallogr F Struct Biol Commun, 71, 1055-1062. PubMed id: 26249699 DOI: 10.1107/S2053230X15011127

Date:

06-May-15 Release date: 20-May-15

Protein chain

P83052  (BBKI_BAUBA) -  Kunitz-type serine protease inhibitor BbKI from Bauhinia bauhinioides

Seq: 164 a.a.

Struc: 163 a.a.

DOI no: 10.1107/S2053230X15011127

Acta Crystallogr F Struct Biol Commun 71:1055-1062 (2015)

PubMed id: 26249699

Structure of BbKI, a disulfide-free plasma kallikrein inhibitor.

D.Zhou, D.Hansen, I.G.Shabalin, A.Gustchina, D.F.Vieira, M.V.de Brito, A.P.Araújo, M.L.Oliva, A.Wlodawer.

ABSTRACT

A serine protease inhibitor from Bauhinia bauhinioides (BbKI) belongs to the Kunitz family of plant inhibitors, which are common in plant seeds. BbKI does not contain any disulfides, unlike most other members of this family. It is a potent inhibitor of plasma kallikrein, in addition to other serine proteases, and thus exhibits antithrombotic activity. A high-resolution crystal structure of recombinantly expressed BbKI was determined (at 1.4 Å resolution) and was compared with the structures of other members of the family. Modeling of a complex of BbKI with plasma kallikrein indicates that changes in the local structure of the reactive loop that includes the specificity-determining Arg64 are necessary in order to explain the tight binding. An R64A mutant of BbKI was found to be a weaker inhibitor of plasma kallikrein, but was much more potent against plasmin, suggesting that this mutant may be useful for preventing the breakup of fibrin and maintaining clot stability, thus preventing excessive bleeding.