Mass Spectrometric Evidence for an Alternate Disulfide Bond in Chloroplast Fructose Bisphosphatase

Photosynth Res. 2004 Feb;79(2):189-200. doi: 10.1023/B:PRES.0000015407.61574.63.

Abstract

Mass mapping analysis based on cyanylation (CN) of the protein and CN-induced cleavage indicates that all three cysteine residues in the insertion into the light-activated pea leaf chloroplast fructose bisphosphatase (E.C. 3.1.3.11) are able to participate in disulfide bond formation. There is a major peak in the mass spectrum of the cleavage products indicating that Cys173 forms a disulfide bond with Cys153, consistent with the structure of the oxidized enzyme in PDB files 1d9q and 1dcu, and a minor peak indicating that Cys173 forms an alternate disulfide bond with Cys178. The Cys173-Cys178 disulfide bond was not apparent in the available crystal structures.

Keywords: CN-induced cleavage; alternate disulfide bonds; fructose bisphosphatase; light-activation; mass mapping; redox-regulation.