2m3v

Publication Abstract from PubMed

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, beta0 and alpha6, and unique conformations of the variable insert, the alpha4-alpha5 loop and helix alpha5 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 11A 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.

Ligand Binding Reduces Conformational Flexibility in the Active Site of Tyrosine Phosphatase Related to Biofilm Formation A (TpbA) from Pseudomonasaeruginosa.,Koveal D, Clarkson MW, Wood TK, Page R, Peti W J Mol Biol. 2013 Mar 21. pii: S0022-2836(13)00172-1. doi:, 10.1016/j.jmb.2013.03.023. PMID:23524133^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.