A novel activation mechanism for Clostridial bacteriophage endolysins

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dc.contributor.advisor Moore, Thomas F. en
dc.contributor.advisor Meijers, Rob en
dc.contributor.author Dunne, Matthew Stephen
dc.date.accessioned 2015-08-19T14:54:46Z
dc.date.issued 2014
dc.date.submitted 2014
dc.identifier.citation Dunne, M. S. 2014. A novel activation mechanism for Clostridial bacteriophage endolysins. PhD Thesis, University College Cork. en
dc.identifier.endpage 207
dc.identifier.uri http://hdl.handle.net/10468/1925
dc.description.abstract Bacteriophage-encoded endolysins are produced at the end of the phage lytic cycle for the degradation of the host bacterial cell. Endolysins offer the potential as alternatives to antibiotics as biocontrol agents or therapeutics. The lytic mechanisms of three bacteriophage endolysins that target Clostridium species living under different conditions were investigated. For these endolysins a trigger and release mechanism is proposed for their activation. During host lysis, holin lesion formation suddenly permeabilises the membrane which exposes the cytosol-sequestered endolysins to a sudden environmental shock. This shock is suggested to trigger a conformational switch of the endolysins between two distinct dimer states. The switch between dimer states is proposed to activate a novel autocleavage mechanism that cleaves the linker connecting the N-terminal catalytic domain and the C-terminal domain to release the catalytic domain for more efficient digestion of the bacterial cell wall. Crystal structures of cleaved fragments of CD27L and CTP1L were previously obtained. In these structures cleavage occurs at the stem of the linker connected to the C-terminal domain. Despite a sequence identity of only 22% between 81 residues of the C-terminal domains of CD27L and CTP1L, they represent a novel fold that is identified in a number of different lysins. Within the crystal structures the two distinct dimerization modes are represented: the elongated head‐on dimer and the side-by‐side dimer. Introducing mutations that inhibit either of the dimerization states caused a decrease in the efficiency of both the autocleavage mechanism and the lytic activity of the endolysins. The two dimer states were validated for the full-length endolysins in solution by using right angle light scattering, small angle X‐ray scattering and cross-linking experiments. Overall, the data represents a new type of regulation governed by the C-terminal domains that is used to activate these endolysins once they enter the bacterial cell wall. en
dc.format.mimetype application/pdf en
dc.language.iso en en
dc.publisher University College Cork en
dc.rights © 2014, Matthew S. Dunne. en
dc.rights.uri http://creativecommons.org/licenses/by-nc-nd/3.0/ en
dc.subject Endolysin en
dc.subject Bacteriophage en
dc.subject Crystallography en
dc.subject Clostridia en
dc.subject Small angle x-ray scattering en
dc.subject Activation mechanism en
dc.title A novel activation mechanism for Clostridial bacteriophage endolysins en
dc.type Doctoral thesis en
dc.type.qualificationlevel Doctoral en
dc.type.qualificationname PhD (Science) en
dc.internal.availability Full text available en
dc.description.version Accepted Version
dc.description.status Not peer reviewed en
dc.internal.school Biochemistry en
dc.check.reason This thesis is due for publication or the author is actively seeking to publish this material en
dc.check.opt-out Not applicable en
dc.thesis.opt-out false
dc.check.entireThesis Entire Thesis Restricted
dc.check.embargoformat E-thesis on CORA only en
ucc.workflow.supervisor t.moore@ucc.ie
dc.internal.conferring Autumn Conferring 2014

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© 2014, Matthew S. Dunne. Except where otherwise noted, this item's license is described as © 2014, Matthew S. Dunne.
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