Documentation scienceplus.abes.fr version Bêta

À propos de : Structural Determinants of the Catalytic Reactivity of the Buried Cysteine ofEscherichia coli Thioredoxin        

AttributsValeurs
type
Is Part Of
Subject
Title
  • Structural Determinants of the Catalytic Reactivity of the Buried Cysteine ofEscherichia coli Thioredoxin
has manifestation of work
related by
Author
Abstract
  • The structurally homologous thioredoxins andthioltransferases/glutaredoxins possess a solvent-exposed cysteine sulfur which carries out a nucleophilic attack on thetarget disulfide as well as a structurallyadjacent solvent inaccessible thiol. The mechanistic basis of theessentially exclusive redox reactivity ofthe thioredoxins in contrast to the thiol−disulfide exchangereactions characteristic of the thioltransferaseslies in the relative reactivity of the buried cysteine. A stableanalog of the mixed disulfide state ofEscherichia coli thioredoxin is used to demonstrate apK value of 11.1 for the solvent inaccessibleCys35 thiol. NMR chemical shift pH titration analysis indicates avery low dielectric surrounding the Cys35 sulfur providing a basis for both the elevated pK and theenhanced apparent nucleophilicity. Theburied Asp 26 likely serves as the proton sink for the(de)protonation of Cys 35. Relevance to thereactivityof the mammalian protein isomerases is discussed.
article type
is part of this journal



Alternative Linked Data Documents: ODE     Content Formats:       RDF       ODATA       Microdata