1ukf
From Proteopedia
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Crystal Structure of Pseudomonas Avirulence Protein AvrPphB
Overview
AvrPphB is an avirulence (Avr) protein from the plant pathogen Pseudomonas, syringae that can trigger a disease-resistance response in a number of, host plants including Arabidopsis. AvrPphB belongs to a novel family of, cysteine proteases with the charter member of this family being the, Yersinia effector protein YopT. AvrPphB has a very stringent substrate, specificity, catalyzing a single proteolytic cleavage in the Arabidopsis, serine/threonine kinase PBS1. We have determined the crystal structure of, AvrPphB by x-ray crystallography at 1.35-A resolution. The structure is, composed of a central antiparallel beta-sheet, with alpha-helices packing, on both sides of the sheet to form a two-lobe structure. The core of this, structure resembles the papain-like cysteine proteases. The similarity, includes the AvrPphB active site catalytic triad of Cys-98, His-212, and, Asp-227 and the oxyanion hole residue Asn-93. Based on analogy with, inhibitor complexes of the papain-like proteases, we propose a model for, the substrate-binding mechanism of AvrPphB. A deep and positively charged, pocket (S2) and a neighboring shallow surface (S3) likely bind to aspartic, acid and glycine residues in the substrate located two (P2) and three (P3), residues N terminal to the cleavage site, respectively. Further, implications about the specificity of plant pathogen recognition are also, discussed.
About this Structure
1UKF is a Single protein structure of sequence from Pseudomonas syringae pv. phaseolicola. Full crystallographic information is available from OCA.
Reference
The crystal structure of Pseudomonas avirulence protein AvrPphB: a papain-like fold with a distinct substrate-binding site., Zhu M, Shao F, Innes RW, Dixon JE, Xu Z, Proc Natl Acad Sci U S A. 2004 Jan 6;101(1):302-7. Epub 2003 Dec 23. PMID:14694194
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