The structure of insecticidal toxins from Yersinia entomophaga

In collaboration with Mark Hurst, Biosecurity and Biocontrol

The insecticidal tc toxins produced by a number of bacteria form large (~2.5MDa) complexes, where the assembly of up to seven proteins are required to show full insecticidal activity. The general architecture of these complexes has previously been established using single-particle EM analysis, but the structural details of the complexes, and their mode of action, remain obscure. This project aims to elucidate the structures and functions of components of the tc toxin complex from the bacterium Yersinia entomophaga.

Where does Lolitrem B bind to the human BK channel?

In collaboration with Dr Julie Dalziel, Biomembrane Laboratory

The large conductance calcium-activated potassium (BK) channel is both physiologically and medically important, having roles in bladder control, regulation of blood pressure, and motor function, and is therefore a potential target for new pharmaceuticals. Lolitrem B is an indole diterpene thought to be the main compound responsible for “ryegrass staggers”, a condition in which animals grazing on endophyte-infected pastures develop ataxia, tremors, and hypersensitivity to external stimuli. Indirect evidence suggests that Lolitrem B binds to the cytosolic domain of the BK channel. The aim of this project is to establish how the toxin inhibits the channel using a combination of biophysical and electrophysiological techniques.

Reducing greenhouse gas emissions from livestock.

In collaboration with Dr Graeme Attwood, Rumen Biotechnology

Methanobrevibacter ruminantium is an archeaon that is responsible for methane production in the rumen of cows. Methane production from livestock is a major source of greenhouse gas emissions in New Zealand, and methane itself is more than twenty times more potent as a greenhouse gas than carbon dioxide. With funding from the Pastoral Greenhouse Gas Research Consortium, this project aims to structurally and functionally characterise proteins from M. ruminantium which are attractive candidate targets for methane mitigation.