title: Open and shut: crystal structures of the dodecylmaltoside solubilized mechanosensitive channel of small conductance from Escherichia coli and Helicobacter pylori at 4.4 Å and 4.1 Å resolutions.
abstract: The mechanosensitive channel of small conductance (MscS) contributes to the survival of bacteria during osmotic downshock by transiently opening large diameter pores for the efflux of cellular contents before the membrane ruptures. Two crystal structures of the Escherichia coli MscS are currently available, the wild type protein in a nonconducting state at 3.7 Å resolution (Bass et al., Science 2002; 298:1582-1587) and the Ala106Val variant in an open state at 3.45 Å resolution (Wang et al., Science 2008; 321:1179-1183). Both structures used protein solubilized in the detergent fos-choline-14. We report here crystal structures of MscS from E. coli and Helicobacter pylori solubilized in the detergent β-dodecylmaltoside at resolutions of 4.4 and 4.2 Å, respectively. While the cytoplasmic domains are unchanged in these structures, distinct conformations of the transmembrane domains are observed. Intriguingly, β-dodecylmaltoside solubilized wild type E. coli MscS adopts the open state structure of A106V E. coli MscS, while H. pylori MscS resembles the nonconducting state structure observed for fos-choline-14 solubilized E. coli MscS. These results highlight the sensitivity of membrane protein conformational equilibria to variations in detergent, crystallization conditions, and protein sequence.
authors: Division of Chemistry and Chemical Engineering, Howard Hughes Medical Institute, California Institute of Technology, Pasadena, California 91125, USA.
authors: Jeffrey Y
authors: JY
authors: Lai
authors: Yan Shuen
authors: YS
authors: Poon
authors: Jens T
authors: JT
authors: Kaiser
authors: Douglas C
authors: DC
authors: Rees
mesh_terms: D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry*; D018360:Crystallography, X-Ray; D003902:Detergents / Q000737:chemistry; D004926:Escherichia coli / Q000737:chemistry* / Q000378:metabolism; D029968:Escherichia coli Proteins / Q000737:chemistry*; D005960:Glucosides / Q000737:chemistry; D016480:Helicobacter pylori / Q000737:chemistry* / Q000378:metabolism; D007473:Ion Channels / Q000737:chemistry*; D008958:Models, Molecular; D008969:Molecular Sequence Data; D011487:Protein Conformation; D011994:Recombinant Proteins / Q000737:chemistry; D016415:Sequence Alignment; D012995:Solubility
chemical_list: D001426:Bacterial Proteins; D003902:Detergents; D029968:Escherichia coli Proteins; D005960:Glucosides; D007473:Ion Channels; C469542:MscS protein, E coli; D011994:Recombinant Proteins; C040358:dodecyl maltoside