pubmed.ncbi.nlm.nih.gov

Electron capture dissociation distinguishes a single D-amino acid in a protein and probes the tertiary structure - PubMed

Comparative Study

. 2004 Jul;15(7):1087-98.

doi: 10.1016/j.jasms.2004.04.026.

Affiliations

Free article

Comparative Study

Electron capture dissociation distinguishes a single D-amino acid in a protein and probes the tertiary structure

Christopher M Adams et al. J Am Soc Mass Spectrom. 2004 Jul.

Free article

Abstract

First results are reported on the application of ECD in analysis of 2+ and 3+ ions of stereoisomers of Trp-cage (NLYIQWLKDGGPSSGRPPPS), the smallest and fastest-folding protein, which exhibits a tightly folded tertiary structure in solution. The chiral recognition based on the ratios of the abundances of z(18) and z(19) fragments in ECD of 2+ ions was excellent even for a single amino acid (Tyr) D-substitution (R(chiral) = 8.6). The chiral effect decreased with an increase of temperature at the electrospray ion source, as well as at a higher degree of ionization, 3+ ions (R(chiral) = 1.5). A general approach is suggested for charge localization in n+ ions by analysis of ECD mass spectra of (n + 1)+ ions. Application of this approach to 3+ Trp-cage ions revealed the protonation probability order in 2+ ions: Arg(16) >> Gln(5) > approximately N-terminus. The ECD results for native form of the 2+ ions favor the preservation of the solution-phase tertiary structure, and chiral recognition through the interaction between the charges and the neutral bond network. Conversely, ECD of 3+ ions supports the dominance of ionic hydrogen bonding which determines a different gas-phase structure than found in solution. Vibrational activation of 2+ ions indicated greater stability of the native form, but the fragmentation patterns did not provide stereoisomer differentiation, thus underlying the special position of ECD among other MS/MS fragmentation techniques. Further ECD studies should yield more structural information as well as quantitative single-amino acid D/L content measurements in proteins.

PubMed Disclaimer

Similar articles

Cited by

References

    1. J Am Chem Soc. 2003 Jun 4;125(22):6628-9 - PubMed
    1. Phys Rev Lett. 2003 Oct 10;91(15):158102 - PubMed
    1. Anal Chem. 2001 Jul 1;73(13):2998-3005 - PubMed
    1. J Mass Spectrom. 1998 Oct;33(10):911-20 - PubMed
    1. Rapid Commun Mass Spectrom. 2002;16(24):2260-5 - PubMed

Publication types

MeSH terms

Substances