title: Dynamical properties of the MscL of Escherichia coli: a normal mode analysis.
abstract: The mechanosensitive channel (MscL) is an integral membrane protein which gates in response to membrane tension. Physiological data have shown that the gating transition involves a very large change in the conformation, and that the open state of the channel forms a large non-specific pore with a high conductance. The Escherichia coli channel structure was first modeled by homology modeling, starting with the X-ray structure of the homologous from Mycobacterium tuberculosis. Then, the dynamical and conformational properties of the channel were explored, using normal mode analysis. Such an analysis was also performed with the different structures proposed recently by Sukharev and co-workers. Similar dynamical behaviors are observed, which are characteristic of the channel architecture, subtle differences being due to the different relative positioning of the structural elements. The ability of particular regions of the channel to deform is discussed with respect to the functional and structural properties, implied in the gating process. Our results show that the first step of the gating mechanism can be described with three low-frequency modes only. The movement associated to these modes is clearly an iris-like movement involving both tilt and twist rotation.
authors.affiliation: Equipe de Bioinformatique Génomique et Moléculaire, EMI03-46, Université Paris 7, 2, place Jussieu, case 7113, 75251 Cedex 05, Paris, France.
authors.forename: H
authors.initials: H
authors.lastname: Valadié
authors.forename: J J
authors.initials: JJ
authors.lastname: Lacapcre
authors.forename: Y-H
authors.initials: YH
authors.lastname: Sanejouand
authors.forename: C
authors.initials: C
authors.lastname: Etchebest
mesh_terms: D000595:Amino Acid Sequence; D018360:Crystallography, X-Ray; D004926:Escherichia coli / Q000378:metabolism; D029968:Escherichia coli Proteins / Q000737:chemistry* / Q000378:metabolism; D015640:Ion Channel Gating / Q000502:physiology*; D007473:Ion Channels / Q000737:chemistry* / Q000378:metabolism; D040542:Mechanotransduction, Cellular; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009068:Movement; D009169:Mycobacterium tuberculosis / Q000378:metabolism; D011487:Protein Conformation; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D040681:Structural Homology, Protein
chemical_list: D029968:Escherichia coli Proteins; D007473:Ion Channels; C086596:MscL protein, E coli