426회 Redox-switch mechanism of E. coli Hsp33 – structural overview

426회 (2009. 5. 14.)

연사:  원 형 식, 건국대학교

제목:  Redox-switch mechanism of E. coli Hsp33 – structural overview

Abstract 

The accumulation of reactive oxygen species (ROS), a condition termed oxidative stress, is deleterious to cells and organisms, due to unfavorable oxidation of most cellular macromolecules. A growing number of proteins have been identified that use the oxidation state to modulate their activity, thereby protecting cells from severe oxidative stress. One such protein is the redox- regulated molecular chaperone Hsp33. Like other heat shock proteins, the expression of Hsp33 is under regulation of heat at transcriptional level but post-translationally, it exhibits a holdase activity upon response to oxidative stress. The redox-switch regulation of Hsp33 is obtained via a folding- unfolding process associated with a metal binding. Despite several crystal structures available, structural details about the redox-switch mechanism have been controversial. In this talk, a historical overview of structural studies on Hsp33 is provided and recent achievements by using NMR in our laboratory are presented. The present results include backbone NMR assignments and secondary structure determination. From the results, it is suggested that certain regions involving a -sheet by -strands 1 and 10 and the -helix 1 segments would be under dynamic conformational equilibrium, which would be crucial for Hsp33 to sense heat and redox status and to undergo conformational transition.