TITLE: Recent NMR and Biophysical Studies of Recombinant Hemoglobins: New Insights into the Structure-Function Relationship in Hemoglobin

SPEAKER: Professor Chien Ho

TIME: Thursday Apr. 4, 2002 at 4 PM

PLACE: George P. Williams, Jr. Lecture Hall, (Olin 101)

Hemoglobin is one of the most studied proteins and has served as a model for understanding intra- and inter-molecular interactions and for gaining insights into signaling pathways in multimeric, allosteric proteins. The oxygenation process of human normal adult hemoglobin (Hb A) is cooperative and the oxygen-binding properties are modulated by interactions of specific amino acid residues with allosteric effectors. By comparing the crystal structures of Hb A in the deoxy and ligated states, Perutz and co workers have described detailed tertiary and quaternary structures of Hb A and have proposed a structural basis for the cooperative oxygenation of this protein. However, the detailed mechanism for the cooperative oxygenation of Hb A is not fully understood and remains controversial. With the development of an expression plasmid to produce authentic Hb A in Escherichia coli, we can design and express any mutant hemoglobins and can also produce isotopically (²H, ¹³C, and ¹⁵N)-labeled hemoglobins needed for our research. Using these mu tant hemoglobins and isotopically labeled hemoglobins, we have carried out biochemical and NMR studies on the structure-function relationship of hemoglobin in solution. In this presentation, we shall describe our recent findings on hemoglobins.