Colin A Wraight (1946-2014)
- Professor Emeritus of Biochemistry
- Professor of Physiology & Biophysics
- Professor of Plant Biology
- Affiliate, Department of Molecular and Integrative Physiology
“He was the first one to show that bacterial reaction centers converted light energy into chemical energy with almost 98% efficiency, and that certain herbicides function by displacing a specific bound quinone molecule.”
—Dr. Govindjee, Professor Emeritus of Biophysics and Plant Biology and longtime friend and colleague of Wraight's.
The Department of Biochemistry
will host a Memorial Symposium
weekend in honor of Colin Wraight
Friday and Saturday, October 9-10, 2015.
Professor Colin A. Wraight passed away July 10, 2014 at the age of 68 after a long and heroic struggle with cancer. Professor Wraight employed biochemical and biophysical methods to understand how the structure of membrane proteins allowed them to catalyze the transfer of electrons and protons in biological energy conversion, processes fundamental to life on this planet.
Born in 1945 in London, UK, Wraight studied at the University of Bristol, earning his B.S. in 1967 and his PhD in 1971. After postdoctoral research at the University of Leiden and Cornell University, and a brief faculty position at the University of California at Santa Barbara, he joined the faculty at the University of Illinois at Urbana-Champaign in 1975 as an Assistant Professor in the Departments of Plant Biology, Physiology, and Biophysics. He held many positions during his years on the faculty of the university, including serving as Director of the Center for Biophysics and Computational Biology from 1995-1999. He joined the Biochemistry Department in 1999 and served as Head of Biochemistry from 2004-2009. He also held faculty positions in the Departments of Plant Biology and Molecular & Integrative Physiology.
In addition to his important research contributions, Professor Wraight was a passionate teacher and mentor, and an outstanding colleague who gave unselfishly to others. He was known for the breadth and depth of his knowledge, quick wit, and the gracious hospitality that he and his wife, Mary, extended to all. His dedication to teaching and graduate training even during his illness was an inspiration to all who knew him.
He is survived by Mary and their children, Lydia, Tristan and Sebastian.
- B.S. 1967 Bristol University, U.K.
- Ph.D. 1971 Bristol University, U.K.
- Postdoc. 1971-72 University of Leiden, The Netherlands, 1972-74 Cornell University
Electron and proton transfer in proteins and across membranes; biological energy conversion; control of redox cofactor function; molecular engineering of ligand-protein interactions
Research Wraight's lab addressed 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. Our approach is physical biochemistry, using kinetic and spectroscopic methods combined with site directed mutagenesis. The fundamental question was broken down into several more specific questions, with very general significance for mechanistic biology:
- how do proteins recognize and bind other molecules (antigens, substrates, cofactors, inhibitors, and other proteins) with great specificity?
- how are cofactor properties modified through protein-ligand interactions?
- how are protons transferred through proteins (the vast majority of biological catalytic mechanisms involve proton transfers)?
- how are electrons transferred from one redox center to another, over long distances?
- what is the role of conformational mobility in protein function?
Wraight's primary research materials were membrane proteins and membrane preparations of bacterial and plant photosynthesis, and respiration, especially the reaction centers and cytochrome bc1 complexes of purple bacteria. These, and other, multifunctional membrane protein complexes transform energy input (light and food) into metabolic electrochemical free energy with high efficiency and yield. Conversion occurs in reaction sequences that span picoseconds to seconds and involving very many cofactors, e.g., hemes, chlorophylls, iron sulfur centers, quinones, flavins. The structures of many of these large complexes have been determined by X-ray diffraction to about 2 Å resolution, a level of structural detail that allows us to seek mechanistic understanding at a molecular level. The extreme functionality of these proteins - the reaction center has at least 8 distinct forward and backward electron transfer steps - makes these studies both challenging and rich in prospects. As well as providing the sites of chemical reaction, the many cofactors exhibit a wealth of spectroscopic characteristics, making them unparalleled in the observability of their functions and the underlying interactions that determine them.
Working with isolated protein complexes and with intact membranes, were are using biochemical and biophysical techniques (e.g., UV-vis kinetic spectroscopy, FTIR (Fourier transform infrared) spectroscopy, EPR, X-ray crystallography, photovoltage measurement, electrochemistry), mutagenesis, and computational methods to study: (1) charge separating and stabilizing reactions - intra-protein electron and proton transfer; (2) electrogenic steps in biological energy conversion - trans-membrane electron and proton transfer; (3) cofactor binding and modulation of function by the protein; and (4) protein electrostatics and conformational dynamics.
The reaction center from the photosynthetic bacterium Rhodobacter sphaeroides (the membrane plane is horizontal). The quasi-two fold symmetry axis, which runs vertically, creates pairs of identical cofactors with very different properties. Examination of the protein-cofactor interactions provides insight to how Nature works at the atomic level.
Maróti, A, Wraight, C.A., Maróti,P. (2015): The rate of second electron transfer to QB–in bacterial reaction center of impaired proton delivery shows hydrogen-isotope effect. Biochim. Biophys. Acta 1847, 223–230.
Taguchi, A. T., P. J. O‘Malley, C. A. Wraight, S. A. Dikanov (2014) Nuclear hyperfine and quadrupole tensor characterization of the nitrogen hydrogen bond donors to the semiquinone of the QB site in bacterial reaction centers: a combined X- and S-band 14,15N ESEEM and DFT study. J. Phys. Chem. B. 118, 1501-1509.
Taguchi, A. T., P. J. O&lsqou;Malley, C. A. Wraight, and S. A. Dikanov (2013) Conformational Differences between the Methoxy Groups of QA and QB Site Ubisemiquinones in Bacterial Reaction Centers: A Key Role for Methoxy Group Orientation in Modulating Ubiquinone Redox Potential. Biochemistry 52, 4648–4655
Martin, E. W., Baldansuren, A., Lin, T-J., Samoilova, R. I., Wraight, C. A., Dikanov, S. A. O'Malley, P. J. (2013) Hydrogen Bonding between the QB Site Ubisemiquinone and Ser-L223 in the Bacterial Reaction Center: A Combined Spectroscopic and Computational Perspective. Biochemistry 51, 9086-9093
Martin, E. W., Samoilova, R. I., Narasimhulu, K. V., Lee, T.-J., O'Malley, P. J., Wraight, C. A., Dikanov, S. A. (2011) Hydrogen bonding and spin density distribution in the QB semiquinone of bacterial reaction centers and comparison with the QA site. J. Am. Chem. Soc. 133, 5525-5533
Kokhan, O., V.P. Shinkarev and C.A.Wraight. (2010). Binding of imidazole to the heme of cytochrome c1 and inhibition of the bc1 complex from Rhodobacter sphaeroides. I. Equilibrium and modeling studies. J. Biol. Chem. 285:22513-22521. [Abstract]
Kokhan, O., V.P. Shinkarev and C.A.Wraight (2010) Binding of imidazole to the heme of cytochrome c1 and inhibition of the bc1 complex from Rhodobacter sphaeroides. II. Kinetics and mechanism of binding. J. Biol. Chem. 285:22522-22531. [Abstract]
Martin, E. W., R. I. Samoilova, K. V. Narasimhulu, C. A. Wraight, and S. A. Dikanov (2010) Hydrogen bonds between nitrogen donors and the semiquinone in the QB-site of the bacterial reaction center. J. Am. Chem. Soc. 132, 11671-11677.
Ham, M. H., J. H. Choi , A. A. Boghossian, E. S. Jeng, R. A. Graff, D. A. Heller, A. C. Chang, A. Mattis, T. H. Bayburt, Y. V. Grinkova, A. S. Zeiger, K. van Vliet, E. K. Hobbie, S. G. Sligar, C. A. Wraight, and M. S. Strano (2010) Photoelectrochemical complexes for solar energy conversion that chemically and autonomously regenerate. Nature Chemistry 2, 929-936.
Kokhan, O., C. A. Wraight and E. Tajkhorshid (2010) The binding interface of cytochrome c and cytochrome c1 in the bc1 complex: Rationalizing the role of key residues. Biophys. J. 99, 2647-2656.
Wraight, C. A., A. S. Vakkasoglu, Y. Poluektov, A. Mattis, E. Takahashi, D. Nihan and B. H. Lipshutz (2008) The 2-methoxy group of ubiquinone is essential for function of the acceptor quinones in reaction centers from Rba. sphaeroides. Biochim. Biophys. Acta 1777, 631-636
Wraight, C. A. and M. R. Gunner (2008) The Acceptor Quinones of Purple Photosynthetic Bacteria – Structure and Spectroscopy. In: The Purple Phototrophic Bacteria (C. N. Hunter, F. Daldal, M. C. Thurnauer, J. T. Beatty, eds), Ch. 20, pp. 379-405. Springer, The Netherlands.
Zhang H., S. E. Chobot, A. Osyczka, C.A. Wraight, P. L. Dutton and C. C. Moser (2008) Quinone and non-quinone redox couples in Complex III. J. Bioenerg. Biomembr. 40, 493-499.
Shinkarev, V.P. and C.A. Wraight (2007) Intermonomer electron transfer in the bc1 complex dimer is controlled by the energized state and by impaired electron transfer between low and high potential hemes. FEBS Letters 581, 1535-1541.
Shinkarev, V. P., A. R. Crofts and C. A. Wraight (2006) In situ kinetics of cytochromes c1 and c2. Biochemistry 45, 7897-7903.
Takahashi, E. and C. A. Wraight (2006) Small weak acids reactivate proton transfer in reaction centers from Rhodobacter sphaeroides mutated at AspL210 and AspM17. J. Biol. Chem. 281, 4413-4422.
Wraight, C. A. (2006) Chance and Design – Proton transfer in water, channels and bioenergetic proteins. Biochim. Biophys. Acta 1757, 886-912.