title: Crystal Structure of Murein-Tripeptide Amidase MpaA from Escherichia coli O157 at 2.6 Å Resolution.
abstract: Peptidoglycan (PG) is an essential component of the cell wall, and undergoes reconstruction by various PG hydrolases during cell growth, development and division. The murein- tripeptide (Mtp) amidase MpaA belongs to PG hydrolase family and is responsible for cleaving the γ-D-Glumeso- Dap amide bond in the Mtp released during PG turnover. The current paper reports the crystal structure of MpaA from Escherichia coli (E. coli) O157 at 2.6 Å resolution. The asymmetric unit consists of two protein molecules and each monomer represents the common α/β fold of metallocarboxypeptidases (MCP). The Tyr133-Asp143 loop appears to mediate the entrance and binding of the substrate into the active groove. A structural comparison of MpaA with its homologue from Vibrio harveyi showed that MpaA has narrower active pocket entrance with a smaller surface opening, which is determined by the Val204-Thr211 loop. The reported structure provides a starting point for the molecular mechanism of MpaA in a significant human pathogen.
authors.forename: Yinliang
authors.initials: Y
authors.lastname: Ma
authors.forename: Guohui
authors.initials: G
authors.lastname: Bai
authors.forename: Yaqi
authors.initials: Y
authors.lastname: Cui
authors.forename: Jing
authors.initials: J
authors.lastname: Zhao
authors.forename: Zenglin
authors.initials: Z
authors.lastname: Yuan
authors.affiliation: No.180 Wusi East Road, Baoding, 071002, Hebei province, China, college of life sciences, Hebei University. China.
authors.forename: Xiuhua
authors.initials: X
authors.lastname: Liu
mesh_terms: D020134:Catalytic Domain; D003001:Cloning, Molecular / Q000379:methods*; D018360:Crystallography, X-Ray; D010450:Endopeptidases / Q000737:chemistry* / Q000235:genetics* / Q000378:metabolism; D019453:Escherichia coli O157 / Q000737:chemistry / Q000201:enzymology* / Q000235:genetics; D029968:Escherichia coli Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D008958:Models, Molecular; D010457:Peptidoglycan; D011485:Protein Binding; D017433:Protein Structure, Secondary
chemical_list: D029968:Escherichia coli Proteins; D010457:Peptidoglycan; D010450:Endopeptidases
keywords: E. coli O157; MpaA; Mtp; PG; crystal structure; mtp amidase