Bacterial Phenotypes and Molecular Mechanisms of Mechanosensitive Channels

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dc.contributor.advisorSukharev, Sergeien_US
dc.contributor.authorShirinian, Lenaen_US
dc.contributor.departmentBiologyen_US
dc.contributor.publisherDigital Repository at the University of Marylanden_US
dc.contributor.publisherUniversity of Maryland (College Park, Md.)en_US
dc.date.accessioned2006-02-04T07:53:04Z
dc.date.available2006-02-04T07:53:04Z
dc.date.issued2005-12-09en_US
dc.description.abstractThis work presents a functional analysis of mutations in two bacterial mechanosensitive channels, MscL and MscS using bacterial growth phenotyping combined with electrophysiological and structural analyses. The introduction of aromatic caps at the ends of lipid facing helices in MscL compromises the osmotic rescuing function of the channel and changes gating parameters. The characteristic absence of aromatic residues at membrane interfaces is critical for MscL function, as the opening transition is associated with a strong helical reorientation. According to the current model of MscS, the pore-forming TM3 helices are predicted to separate, tilt, and straighten upon channel opening. This dynamic transition has been examined using a cysteine scan of this region and MTS accessibility experiments. Both cell viability assays and electrophysiological data support the hypothesis of a helical separation. Conductance measurements in gate mutants suggest that the pore lumen narrows toward the periplasmic end, consistent with the current model.en_US
dc.format.extent2141525 bytes
dc.format.mimetypeapplication/pdf
dc.identifier.urihttp://hdl.handle.net/1903/3246
dc.language.isoen_US
dc.subject.pqcontrolledBiology, Molecularen_US
dc.subject.pqcontrolledBiology, Microbiologyen_US
dc.subject.pqcontrolledBiophysics, Generalen_US
dc.titleBacterial Phenotypes and Molecular Mechanisms of Mechanosensitive Channelsen_US
dc.typeThesisen_US

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