Current Projects

Mechanisms of Stabilization of b Hemoproteins

Funded by the National Institutes of Health
GM-54217

The ability to design functional proteins for medical and other uses depends critically on understanding the relationship between amino acid sequence and physico-chemical properties. We seek to investigate the factors essential to the finely tuned capacity of b-hemoproteins to recognize and bind the heme group. The starting point is the apoprotein from cytochrome b₅, a marginally stable globular protein able to bind the heme group reversibly and with high affinity. Heme binding induces structural changes, mostly in the a -helices of the binding site, and dynamic changes throughout the protein. Here, we combine molecular biology, optical spectroscopy, and multinuclear NMR spectroscopy to characterize these changes in wild-type cytochrome b₅ and variants. The perturbations induced by heme binding are mapped on the structure and principles of design are derived from this information.