Defining the disulfide bonds of insulin-like growth factor-binding protein-5 by tandem mass spectrometry with electron transfer dissociation and collision-induced dissociation.

ABSTRACT: The six high-affinity insulin-like growth factor-binding proteins (IGFBPs) comprise a conserved family of secreted molecules that modulate IGF actions by regulating their half-life and access to signaling receptors, and also exert biological effects that are independent of IGF binding. IGFBPs are composed of cysteine-rich amino- (N-) and carboxyl- (C-) terminal domains, along with a cysteine-poor central linker segment. IGFBP-5 is the most conserved IGFBP, and contains 18 cysteines, but only 2 of 9 putative disulfide bonds have been mapped to date. Using a mass spectrometry (MS)-based strategy combining sequential electron transfer dissociation (ETD) and collision-induced dissociation (CID) steps, in which ETD fragmentation preferentially induces cleavage of disulfide bonds, and CID provid

SUBMITTER: Nili M 

PROVIDER: S-EPMC3256881 | biostudies-literature | 2012 Jan

REPOSITORIES: biostudies-literature