Jump to main content
Jump to site search

Issue 7, 2009
Previous Article Next Article

Role of a salt bridge in the model protein crambin explored by chemical protein synthesis: X-ray structure of a unique protein analogue, [V15A]crambin-α-carboxamide

Author affiliations

Abstract

We have used total chemical synthesis to prepare [V15A]crambin-α-carboxamide, a unique protein analogue that eliminates a salt bridge between the δ-guanidinium of the Arg10 side chain and the α-carboxylate of Asn46 at the C-terminus of the polypeptide chain. This salt bridge is thought to be important for the folding and stability of the crambin protein molecule. Folding, with concomitant disulfide bond formation, of the fully reduced [V15A]crambin-α-carboxamidepolypeptide was less efficient than folding/disulfide formation for the [V15A]crambin polypeptide under a standard set of conditions. To probe the origin of this less efficient folding/disulfide bond formation, we separately crystallized purified synthetic [V15A]crambin-α-carboxamide and chemically synthesized [V15A]crambin and solved their X-ray structures. The crystal structure of [V15A]crambin-α-carboxamide showed that elimination of the Arg10Asn46 salt bridge caused disorder of the C-terminal region of the polypeptide chain and affected the overall ‘tightness’ of the structure of the protein molecule. These studies, enabled by chemical protein synthesis, strongly suggest that in native crambin the Arg10Asn46 salt bridge contributes to efficient formation of correct disulfide bonds and also to the well-ordered structure of the protein molecule.

Graphical abstract: Role of a salt bridge in the model protein crambin explored by chemical protein synthesis: X-ray structure of a unique protein analogue, [V15A]crambin-α-carboxamide

Back to tab navigation

Publication details

The article was received on 20 Feb 2009, accepted on 23 Apr 2009 and first published on 28 May 2009


Article type: Paper
DOI: 10.1039/B903610E
Citation: Mol. BioSyst., 2009,5, 750-756
  •   Request permissions

    Role of a salt bridge in the model protein crambin explored by chemical protein synthesis: X-ray structure of a unique protein analogue, [V15A]crambin-α-carboxamide

    D. Bang, V. Tereshko, A. A. Kossiakoff and S. B. H. Kent, Mol. BioSyst., 2009, 5, 750
    DOI: 10.1039/B903610E

Search articles by author

Spotlight

Advertisements