Award details

Enhancement and modulation of a pore-forming toxin.

Reference	BB/C504927/1
Principal Investigator / Supervisor	Dr Neil Crickmore
Co-Investigators / Co-Supervisors
Institution	University of Sussex
Department	Sch of Life Sciences
Funding type	Research
Value (£)	193,865
Status	Completed
Type	Research Grant
Start date	01/02/2005
End date	31/01/2008
Duration	36 months

Abstract

Hypothesis-driven research into the structure-function of the insecticidal Cry1Ac toxin of Bacillus thuringiensis has led to the creation of a variant form of this pore-forming toxin that has greatly increased toxicity towards one of its target organisms ¿ the diamond-back moth. Moreover the same procedure has resulted in increasing the activity of a related toxin, Cry1Ab. Whilst the nature of the modifications made to create the variant toxins is known the molecular mechanism that is responsible for the increased toxicity has not been fully elucidated. This project therefore intends to study the biochemical basis of improved toxicity. Preliminary data suggest that differential proteolyic activation of the toxin may correlate with the differential activity and that events subsequent to the toxin¿s interaction with the surface of the target cell are where the differences in toxicity are manifested. The experimental approaches to be used include protein sequencing, mass spectrometry and circular dichroism to characterise the differentially activated forms of the native and variant toxin. Membrane and solution-based oligomerisation assays will be employed to investigate whether differences in the formation of a pre-pore oligomeric structure might be responsible for the increased activity. Pore-forming assays will also be employed using membranes derived from the target insect cells, as well as planar lipid bilayers, in order to investigate differences in the pore-forming capability of the toxins. Finally a mutagenesis approach will be used to more closely define which amino acid differences in the variant toxin are responsible for the enhanced phenotype.

Summary

unavailable

Committee	Closed Committee - Biochemistry & Cell Biology (BCB)
Research Topics	X – not assigned to a current Research Topic
Research Priority	X – Research Priority information not available
Research Initiative	X - not in an Initiative
Funding Scheme	X – not Funded via a specific Funding Scheme

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