Christina Redfield
NMR studies of protein structure, function, folding and dynamics
Co-workers: Paraskevi Kritsiligkou, Despoina Mavridou, Lorena Varela-Alvarez, Louise Walport, Philip Weisshuhn, David Yadin, Matt Young
Our research involves the application of state-of-the-art NMR methods to address a range of biological problems.
(1) The folding of a protein to its functional native state from the information encoded in its amino acid sequence is a key feature of the conversion of genetic information into biological activity. For some proteins partially structured species, known as molten globules, have been observed to form early in folding prior to the formation of the native state. We use NMR to define, at the level of individual residues, the determinants of the structure and stability of the molten globule states of proteins including α-lactalbumin.
(2) In collaboration with Professor Penny Handford, we are using NMR to characterise the structure, dynamics and Ca2+-binding properties of cbEGF domains in proteins including fibrillin-1, Notch and CRB1 and to understand how single amino acid substitutions can perturb these proteins and result in diseases such as Marfan syndrome and Leber’s congenital amaurosis.
(3) In collaboration with Professor Stuart Ferguson, we are using NMR to study the active-site properties and interactions of the redox protein DsbD, which is involved in the disulfide bond and cytochrome c maturation systems. We also aim to understand the importance of the covalently-bound heme in c-type cytochromes by comparing the structure, dynamics and stability of wild-type and b-type variants of cytochrome c 552.
(4) Lysozyme from bacteriophage l is observed in open and closed conformations in X-ray structures. In collaboration with Dr Andre Matagne (Liege) we have used 15N relaxation methods to show that these conformers interconvert rapidly in solution and that the dynamic behaviour is modified in the presence of substrates and inhibitors.
Publications
- D.A.I. Mavridou, J.M. Stevens, S.J. Ferguson and C. Redfield, Active-site properties of the oxidized and reduced C-terminal domain of DsbD obtained by NMR spectroscopy, J. Mol. Biol. 370, 643-658 (2007)
- J.A. Davis, P.A. Handford and C. Redfield, The N1317H substitution associated with Leber congenital amaurosis results in impaired interdomain packing in human CRB1 EGF domains, J. Biol. Chem. 282, 28807-28814 (2007)
- J. Cordle, S. Johnson, J.Z.Y. Tay, P. Roversi, M. Wilkin, B. Hernandez-Diaz, H. Shimizu, S. Jensen, P. Whiteman, B. Jin, C. Redfield, M. Baron, S.M. Lea and P.A. Handford, A conserved face of the Jagged/Serrate DSL domain is involved in Notch trans-activation and cis-inhibition, Nat. Struct. Mol. Biol. 15, 849-857 (2008)
- S. Ramboarina and C. Redfield, Probing the effect of temperature on the backbone dynamics of the human α-lactalbumin molten globule, J. Am. Chem. Soc. 130, 15318-15326 (2008)
- D.A.I. Mavridou, J.M. Stevens, A.D. Goddard, A.C. Willis, S.J. Ferguson and C. Redfield, Control of periplasmic interdomain thiol:disulfide exchange in the transmembrane oxidoreductase DsbD, J. Biol. Chem. 284, 3219-3226 (2009)
More Publications...
Research Images
Figure 1: DsbD is essential for the biogenesis of c-type cytochromes in the periplasm. It functions by transferring electrons from cytoplasmic thioredoxin through its transmembrane domain to its C-terminal domain and finally to its N-terminal domain. This occurs via a disulfide cascade involving three pairs of cysteines. NMR spectroscopy has been used to measure the pKa values of the cysteine residues in the C-terminal domain. Two acidic residues, D455 and E468, are responsible for the unusually high pKa value of 10.5 measured for C461 in the C-terminal domain of DsbD. (with Prof. Stuart Ferguson, cover of the 20 July 2007 issue of the Journal of Molecular Biology)
Figure 2: Non-cooperative unfolding of the molten globule of α-lactalbumin at low pH can be monitored by NMR. The bars indicate the concentration of urea at which an HSQC peak is first observed for each residue. The unfolding behaviour is mapped on to the native structure of α-LA; residues presumed to be in a collapsed structure at a particular urea concentration are indicated with a space-filling representation
Contact:christina.redfield@bioch.ox.ac.uk
Graduate Student and Postdoctoral Positions: Enquiries with CV welcome