Alkyl isocyanides serve as transition state analogues for ligand entry and exit in myoglobin.

ABSTRACT: Alkyl isocyanides (CNRs) identify pathways for diatomic ligand movement into and out of Mb, with their side chains acting as transition state analogues. The bound alkyl groups point either into the back of the distal pocket (in conformation, nu(CN) approximately 2070-2090 cm(-1)), which allows hydrogen bond donation from His64(E7) to the isocyano group, or toward solvent through an open His(E7) channel (out conformation, nu(CN) approximately 2110-2130 cm(-1)), which prevents polar interactions with the isocyano atoms. Fractions of the in conformer (F(in)) were measured by FTIR spectroscopy for methyl through n-pentyl isocyanide bound to a series of 20 different distal pocket mutants of sperm whale myoglobin and found to be governed by the ease of rotation of the His(E7) side chain, distal

SUBMITTER: Blouin GC 

PROVIDER: S-EPMC4102008 | biostudies-literature | 2010 Jun

REPOSITORIES: biostudies-literature