Disulfide Bond Assignments by Mass Spectrometry of Native Natural Peptides: Cysteine Pairing in Disulfide Bonded Conotoxins


Autoria(s): Gupta, Kallol; Kumar, Mukesh; Balaram, Padmanabhan
Data(s)

15/09/2010

Resumo

The critical, and often most difficult, step in structure elucidation of diverse classes of natural peptides is the determination of correct disulfide pairing between multiple cysteine residues. Here, we present a direct mass spectrometric analytical methodology for the determination of disulfide pairing. Protonated peptides, having multiple disulfide bonds, fragmented under collision induced dissociation (CID) conditions and preferentially cleave along the peptide backbone, with occasional disulfide fragmentation either by C-beta-S bond cleavage through H-alpha abstraction to yield dehydroalanine and cysteinepersulfide, or by S-S bond cleavage through H-beta abstraction to yield the thioaldehyde and cysteine. Further fragmentation of the initial set of product ions (MSn) yields third and fourth generation fragment ions, permitting a distinction between the various possible disulfide bonded structures. This approach is illustrated by establishing cysteine pairing patterns in five conotoxins containing two disulfide bonds. The methodology is extended to the Conus araneosus peptides An 446 and Ar1430, two 14 residue sequences containing 3 disulfide bonds. A distinction between 15 possible disulfide pairing schemes becomes possible using direct mass spectral fragmentation of the native peptides together with fragmentation of enzymatically nicked peptides.

Formato

application/pdf

Identificador

http://eprints.iisc.ernet.in/33580/1/dis.pdf

Gupta, Kallol and Kumar, Mukesh and Balaram, Padmanabhan (2010) Disulfide Bond Assignments by Mass Spectrometry of Native Natural Peptides: Cysteine Pairing in Disulfide Bonded Conotoxins. In: Analytical Chemistry, 82 (19). pp. 8313-8319.

Publicador

American Chemical Society

Relação

http://pubs.acs.org/doi/abs/10.1021/ac101867e

http://eprints.iisc.ernet.in/33580/

Palavras-Chave #Molecular Biophysics Unit
Tipo

Journal Article

PeerReviewed