Seminars Archive

Atomic Resolution Crystallographic Analysis of a Flavoenzyme: Studying the Role of Protein Dynamics in Catalysis.

Abstract


Monday, December 13, 2004, 15:00
Seminar Room, ground floor, Building "T"
Sincrotrone Trieste, Basovizza
Atomic Resolution Crystallographic Analysis of a Flavoenzyme:

Studying the Role of Protein Dynamics in Catalysis.




Alice Vrielink

(University of California Santa Cruz)
Abstract
Recent technical advances in macromolecular crystallographic analysis, particularly the availability of high intensity, tunable and well collimated X-rays from synchrotron radiation beamlines and the ability to cryo-protect crystals thus enhancing their lifetimes has provided opportunities to study protein structures at much higher resolution that previously attainable. These atomic resolution structures give important structural information at a much higher level of detail. For example hydrogen atoms become interpretable in the electron density maps providing important information on hydrogen bonding and orientation. In addition a more detailed view of the solvent structure within the protein is possible allowing a better understanding of the role of protein hydration on biological function and protein stability. Furthermore, the additional data available from atomic resolution diffraction enables multiple amino acid side chain conformations to be visualized and refined as well as individual anisotropic temperature factors thereby providing important information on protein dynamics. An atomic resolution (0.95) crystallographic study of cholesterol oxidase, a soluble flavoenzyme that interacts at a membrane interface to oxidize and isomerizes cholesterol, will be presented. This atomic resolution structure has enabled structural features, not evident in previous high resolution (1.5) structures, to be visualized providing a new understanding of the dynamics involved in substrate binding and flavin mediated enzyme catalysis.