Ligand Binding Reduces Conformational Flexibility in the Active Site of Tyrosine Phosphatase Related to Biofilm Formation A (TpbA) from Pseudomonas aeruginosa

JOURNAL OF MOLECULAR BIOLOGY

卷:425

Article

Koveal, Dorothy¹  Clarkson, Michael W.²  Wood, Thomas K.³  Page, Rebecca¹  Peti, Wolfgang^2,4 

[1] Brown Univ, Dept Mol Biol Cell Biol & Biochem, Providence, RI 02903 USA

[2] Brown Univ, Dept Mol Pharmacol Physiol & Biotechnol, Providence, RI 02903 USA

[3] Penn State Univ, Dept Chem Engn, University Pk, PA 16802 USA

[4] Brown Univ, Dept Chem, Providence, RI 02903 USA

关键词: dual-specificity phosphatase;    NMR spectroscopy;    open/closed state active-site dynamics;    bacterial signaling;    Pseudomonas aeruginosa;   

DOI  :  10.1016/j.jmb.2013.03.023

来源: Elsevier

【 摘 要 】

Tyrosine phosphatase related to biofilm formation A (TpbA) is a periplasmic dual-specificity phosphatase (DUSP) that controls biofilm formation in the pathogenic bacterium Pseudomonas aeruginosa. While DUSPs are known to regulate important cellular functions in both prokaryotes and eukaryotes, very few structures of bacterial DUSPs are available. Here, we present the solution structure of TpbA in the ligand-free open conformation, along with an analysis of the structural and dynamic changes that accompany ligand/phosphate binding. While TpbA adopts a typical DUSP fold, it also possesses distinct structural features that distinguish it from eukaryotic DUSPs. These include additional secondary structural elements, beta 0 and alpha 6, and unique conformations of the variable insert, the alpha 4-alpha 5 loop and helix alpha 5 that impart TpbA with a flat active-site surface. In the absence of ligand, the protein tyrosine phosphatase loop is disordered and the general acid loop adopts an open conformation, placing the catalytic aspartate, Asp105, more than 11 angstrom away from the active site. Furthermore, the loops surrounding the active site experience motions on multiple timescales, consistent with a combination of conformational heterogeneity and fast (picosecond to nanosecond) timescale dynamics, which are significantly reduced upon ligand binding. Taken together, these data structurally distinguish TpbA and possibly other bacterial DUSPs from eukaryotic DUSPs and provide a rich picture of active-site dynamics in the ligand-free state that are lost upon ligand binding. (c) 2013 Elsevier Ltd. All rights reserved.

【 授权许可】

Free