1ukf: Difference between revisions

[[Image:1ukf.jpg|left|200px]]<br /><applet load="1ukf" size="350" color="white" frame="true" align="right" spinBox="true"  

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.

1UKF is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Pseudomonas_syringae_pv._phaseolicola Pseudomonas syringae pv. phaseolicola]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1UKF OCA].  

[[Category: Dixon, J E.]]

[[Category: Innes, R W.]]

''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 15:25:34 2008''