Structure of an Open Form of an E. coli Mechanosensitive Channel at 3.45 Å Resolution

• Published in: Science (American Association for the Advancement of Science) Vol. 321; no. 5893; pp. 1179 - 1183
• Main Authors: Wang, Wenjian, Black, Susan S, Edwards, Michelle D, Miller, Samantha, Morrison, Emma L, Bartlett, Wendy, Dong, Changjiang, Naismith, James H, Booth, Ian R
• Format: Journal Article
• Language: English
• Published: Washington, DC American Association for the Advancement of Science 29.08.2008
• Subjects: Biological and medical sciences; Cell Membrane - chemistry; Crystal structure; Crystallography, X-Ray; Electric Conductivity; Escherichia coli; Escherichia coli - chemistry; Escherichia coli - physiology; Escherichia coli Proteins - chemistry; Escherichia coli Proteins - genetics; Escherichia coli Proteins - physiology; Free energy; Fundamental and applied biological sciences. Psychology; Hydrophobic and Hydrophilic Interactions; Ion Channel Gating; Ion channels; Ion Channels - chemistry; Ion Channels - genetics; Ion Channels - physiology; Kinetics; Microbiology; Modeling; Models, Molecular; Molecules; Monomers; Morphology, structure, chemical composition, physicochemical properties; Mutant Proteins - chemistry; mutants; Mutation; P branes; Patch-Clamp Techniques; Pressure; Protein Conformation; Protein Structure, Secondary; Protein Structure, Tertiary; Research Article; String theory; turgor; Vapors; Virology; Three dimensional structure; Molecular structure; Escherichia coli; Bacteria; Ionic channel; Membrane channel; Enterobacteriaceae; Conformation
• ISSN: 0036-8075; 1095-9203; 1095-9203
• DOI: 10.1126/science.1159262

How ion channels are gated to regulate ion flux in and out of cells is the subject of intense interest. The Escherichia coli mechanosensitive channel, MscS, opens to allow rapid ion efflux, relieving the turgor pressure that would otherwise destroy the cell. We present a 3.45 angstrom-resolution structure for the MscS channel in an open conformation. This structure has a pore diameter of ~13 angstroms created by substantial rotational rearrangement of the three transmembrane helices. The structure suggests a molecular mechanism that underlies MscS gating and its decay of conductivity during prolonged activation. Support for this mechanism is provided by single-channel analysis of mutants with altered gating characteristics.