The effect of point mutation on the equilibrium structural fluctuations of ferric Myoglobin.

Department of Physics, University of Strathclyde, Glasgow, Scotland, UK. katrin.adamczyk@strath.ac.uk

Physical chemistry chemical physics : PCCP 2012 May 28

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The ultrafast equilibrium fluctuations of the Fe(III)-NO complex of a single point mutation of Myoglobin (H64Q) have been studied using Fourier Transform 2D-IR spectroscopy. Comparison with data from wild type Myoglobin (wt-Mb) shows the presence of two conformational substates of the mutant haem pocket where only one exists in the wild type form. One of the substates of the mutant exhibits an almost identical NO stretching frequency and spectral diffusion dynamics to wt-Mb while the other is distinctly different in both respects. The remarkably contrasting dynamics are largely attributable to interactions between the NO ligand and a nearby distal side chain which provides a basis for understanding the roles of these side chains in other ferric haem proteins.

Citation

Katrin Adamczyk, Marco Candelaresi, Rafal Kania, Kirsty Robb, Cesar Bellota-Antón, Gregory M Greetham, Mark R Pollard, Michael Towrie, Anthony W Parker, Paul A Hoskisson, Nicholas P Tucker, Neil T Hunt. The effect of point mutation on the equilibrium structural fluctuations of ferric Myoglobin. Physical chemistry chemical physics : PCCP. 2012 May 28;14(20):7411-9