Colin Wraight

 

Professor of Plant Biology, Biophysics,

and Biochemistry

160 Davenport MC-712
(217) 333-3245

Education

Ph.D., 1971, University of Bristol, England

Teaching

MCB 555,  Analysis of the  Biochemical Literature

Research Overview

Research in my lab addresses the basic question of how protein structure determines function, especially in the context of membrane proteins that catalyze electron and proton transfer in biological energy conversion. The question may be broken down to a few specifics, with very general significance for mechanistic biology:

 

  1. how do proteins recognize and bind other molecules (antigens, substrates, cofactors, inhibitors, etc) with great specificity?
  2. how are cofactor properties modified through protein-ligand interactions?
  3. how are protons transferred through proteins (the vast majority of biological catalytic (enzymic) mechanisms involve proton transfers)?
  4. how are electrons transferred from one redox center to another, over long distances?
  5. what is the role of conformational mobility in protein function?

Our primary research materials are membrane proteins and membrane preparations of bacterial and plant photosynthesis. These include the cytochrome bc1 and b6f complexes of anoxygenic and oxygenic organisms, respectively, and Photosystem II of plants, but especially the reaction center (RC) of purple bacteria. We are investigating the mechanisms whereby photosynthesis converts light into electrochemical free energy with high efficiency and yield. Conversion occurs in these multifunctional membrane protein complexes, in reaction sequence that span picoseconds to milliseconds and involving very many cofactors (e.g., chlorophylls, hemes, iron sulfur proteins and quinones).

 

Working with intact membranes and isolated reaction centers, we are using biophysical techniques (e.g., optical spectroscopy, EPR, photovoltage measurement), mutagenesis, and computational methods to study:

 

  1. charge separating and stabilizing electron transfer reactions;
  2. proton uptake and intra-protein transfer reactions;
  3. electrostatics and dynamics in proteins;
  4. cofactor (quinone) binding and modulation of function by the protein;
  5. electrogenic steps in electron and proton transfer processes;
  6. protein conformational dynamics.

Recent Publications

Wraight CA (2006) Chance and Design – Proton transfer in water, channels and bioenergetic proteins. Biochim. Biophys. Acta 1757, 886-912.


Takahashi E, WraightCA (2006) Small weak acids reactivate proton transfer in reaction centers from Rhodobacter sphaeroides mutated at AspL210 and AspM17.  J. Biol. Chem. 281, 4413-4422.


Shinkarev, VP, Crofts AR, Wraight  CA (2006) Spectral and kinetic resolution of the bc1 complex components in situ: A simple and robust alternative to the traditional difference wavelength approach.  Biochim. Biophys. Acta 1757, 273-283.