*Department of Chemistry, Birkbeck College, University of London, UK and +Delta Biotechnology Ltd, Nottingham, UK
Albumin (66 KDa), the major protein in blood plasma, is composed of three structurally-similar, largely-helical domains, each of which is composed of two subdomains. The protein is involved in the transport of a wide range of drugs, metal ions, fatty acids, hormones and xenobiotics which have regiospecific binding sites. We are using NMR to provide fingerprints of binding to these sites.
The recent X-ray crystal structure of albumin [1] shows that Cys34 is located in a crevice and our 1H NMR studies [2] suggest that a structural transition can take place in solution involving movement of this residue from a buried to an exposed state.
We present here solution-state 1H NMR studies of drug and ligand binding to Cys34 of human albumin and its Cys34Ala mutant. These provide evidence for the crevice opening and insight into the charge interactions which control it. We also show that the drug- and metal-induced structural transition in albumin can be studied directly in human blood plasma.
We thank the BBSRC, MRC, Wellcome Trust, Delta Biotechnology Ltd and ULIRS for their support for this work.
[1] D.C. Carter and J. X. Ho, Adv. Prot. Chem.1994, 45, 153-203.
[2] J. Christodoulou, P.J. Sadler and A. Tucker Eur. J. Biochem. 1994, 225, 363-368.