Bacteriophage P1: a new paradigm for control of phage lysis

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dc.contributor.advisor Young , Ryland en_US
dc.contributor.committeeMember Siegele , Deborah en_US
dc.creator Xu , Min en_US 2005 -11 -01T15 :50 :38Z 2014 -02 -19T19 :23 :05Z 2005 -11 -01T15 :50 :38Z 2014 -02 -19T19 :23 :05Z 2004 -08 en_US 2005 -11 -01T15 :50 :38Z
dc.identifier.uri http : / /hdl .handle .net /1969 .1 /2734
dc.description.abstract The N -terminal hydrophobic domain of the phage P1 endolysin Lyz was found to facilitate the export of Lyz in a sec -dependent fashion , explaining the ability of Lyz to cause lysis of E .coli in the absence of the P1 holin . The N -terminal domain of Lyz is demonstrated to be both necessary and sufficient not only for export to the membrane but also for release into the periplasm of this endolysin . We propose that this unusual N -terminal domain functions as a "signal arrest - release" (SAR ) sequence , which first directs the endolysin to the periplasm in membrane -tethered form and then allows it to be released as a soluble active enzyme in the periplasm . To understand why release from the membrane is required for the physiological expression of the lytic activity of Lyz , we examined the role of its seven cysteine residues in the biogenesis of the active endolysin . The inactive , membrane -tethered and the active , soluble forms of Lyz differ in their pattern of intramolecular disulfide bonding . We conclude that the release of Lyz from the membrane leads to an intramolecular thiol -disulfide bond isomerization causing a dramatic conformational change in the Lyz protein . As a result , an active site cleft that is missing in nascent Lyz is generated in the mature form of the endolysin . Examination of the protein sequences of related bacteriophage endolysins suggests that the presence of an SAR sequence is not unique to Lyz . Studies on holin and antiholin indicated that P1 encodes two holins , LydA and LydC . The antiholin LydB inhibits LydA by binding to it directly on the membrane . All above results demonstrate a new paradigm for control of phage lysis , which is , upon depolarization of the membrane by holin function at a programmed time , endolysin is released from the bilayer leading to the immediate lysis of the host . en_US
dc.format.extent 1674574 bytes
dc.format.medium electronic en_US
dc.format.mimetype application /pdf
dc.language.iso en _US en_US
dc.publisher Texas A &M University en_US
dc.subject Bacteriophage P1 en_US
dc.title Bacteriophage P1 : a new paradigm for control of phage lysis en_US
dc.type Book en
dc.type.genre Electronic Dissertation en_US
dc.type.material text en_US
dc.format.digitalOrigin born digital en_US


Bacteriophage P1: a new paradigm for control of phage lysis. Available electronically from http : / /hdl .handle .net /1969 .1 /2734 .

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