X-ray-based structural models for the in situ X-irradiation of a sulfur-containing enzyme

摘要

The X-ray damage of the sulfhydryl enzyme malate synthase from yeast has been investigated by physicochemical studies including time-resolved small-angle X-ray scattering.Our previous studies already suggested the role of cysteine-sulfenic acid and disulfides in the damage process and established a simple model for the occurring aggregation.The preceding model is now confirmed by ab initio modeling approaches,illustrating the evolution to a 2D aggregation process.Information on the involvement of the sulfur-containing groups was obtained from recourse to crystallographic and sequence data of the E.coli enzyme,using surface and hydration algorithms;the applied approaches prove the existence and localization of sulfhydryl and sulfenic acid sites in the enzyme.