Characterization of deamidation of barstar using electrospray ionization quadrupole time-of-flight mass spectrometry, which stabilizes an equilibrium unfolding intermediate.

ABSTRACT: Deamidation of asparaginyl residues is a common posttranslational modification in proteins and has been studied extensively because of its important biological effects, such as those on enzymatic activity, protein folding, and proteolytic degradation. However, characterization of the sites of deamidation of a protein has been a difficult analytical problem. In this study, mass spectrometry has been used as an analytical tool to characterize the deamidation of barstar, an RNAse inhibitor. Upon incubation of the protein at alkaline pH for 5 h, intact mass analysis of barstar, using electrospray ionization quadrupole time-of-flight mass spectrometry (ESI QToF MS), indicated an increase in the mass of +2 Da, suggesting possible deamidation of the protein. The sites of deamidation have been ide

SUBMITTER: Jha SK 

PROVIDER: S-EPMC3403461 | biostudies-literature | 2012 May

REPOSITORIES: biostudies-literature