Mass spectrometric identification of in vivo carbamylation of the amino terminus of Ectothiorhodospira mobilis high-potential iron–sulfur protein, isozyme 1
✍ Scribed by G. Van Driessche; I. Vandenberghe; F. Jacquemotte; B. Devreese; J. J. Van Beeumen
- Publisher
- John Wiley and Sons
- Year
- 2002
- Tongue
- English
- Weight
- 159 KB
- Volume
- 37
- Category
- Article
- ISSN
- 1076-5174
- DOI
- 10.1002/jms.348
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✦ Synopsis
Abstract
The complete amino acid sequence of a novel high‐potential iron–sulfur protein (HiPIP) isozyme 1 from the moderately halophilic phototrophic bacterium Ectothiorhodospira mobilis was determined by a combined approach of chemical and mass spectrometric sequencing techniques. By mass analysis of the apo‐ and holo‐protein in the positive electrospray ionization mode using different electrospray solvents, the protein was found to be post‐translationally modified by a moiety of 43 Da. Further analysis showed the nature and location of this modification to be a carbamyl group at the N‐terminus of the HiPIP. This rare type of modification has previously been reported to occur in the water‐soluble human lens αB‐crystallin, class D β‐lactamases and some prokaryotic ureases, albeit at an internal lysine residue. In this paper, we discuss the mass spectrometric features of a carbamylated residue at the N‐terminus of a peptide or a lysine side‐chain during sequence analysis by collision‐induced dissociation tandem mass spectrometry. Our data provide evidence for the first case of a prokaryotic carbamylated electron transport protein occurring in vivo. Copyright © 2002 John Wiley & Sons, Ltd.