William Royer of the University of Massachusetts Medical School will present “Regulation of Biological Activity Through Protein Dimerization: Crystallographic Analyses of Invertebrate Hemoglobins and Interferon Regulatory Factors,” at 4 p.m. Feb. 25 in the Beadle Center, Room E103. The seminar is free and open to the public.

Much of biology requires the association of macromolecules through specific interactions. In this seminar, Royer will discuss assembly of subunits in cooperative invertebrate hemoglobins and human interferon regulatory factors along with its impact on function. Conventional and time-resolved crystallographic experiments on simple dimeric hemoglobin have established central roles for both tight interface coupling and interfacial water molecules in the cooperative signal transduction across the dimeric interface.

The dimeric subunit pairing, although distinct from those in mammalian hemoglobins, is conserved among all cooperative invertebrate hemoglobins investigated to date, including giant 3.6 million Dalton complexes. Dimerization, triggered by phosphorylation, also plays a central role in IRF signaling, which is key for the innate immune response. Crystal structures show that phosphorylation of IRFs is accompanied by dramatic structural transitions that couple dimerization with binding of the activator CBP, a key event in triggering transcription of interferon and other cytokines.

The Beadle Center is located at 1901 Vine St. The complete schedule of seminars can be found at http://biotech.unl.edu/.