2bli

From Proteopedia

Revision as of 15:37, 5 November 2007

L29W MB DEOXY

Overview

We have determined eight X-ray structures of myoglobin mutant L29W at, various experimental conditions. In addition, infrared spectroscopic, experiments are presented, which are discussed in the light of the X-ray, structures. Two distinct conformations of the CO-ligated protein were, identified, giving rise to two stretching bands of heme-bound CO. If L29W, MbCO crystals are illuminated around 180 K, a deoxy species is formed. The, CO molecules migrate to the proximal side of the heme and remain trapped, in the so-called Xe1 cavity upon temperature decrease to 105 K. The, structure of this photoproduct is almost identical to the equilibrium, high-temperature deoxy Mb structure. If the temperature is cycled to, increasingly higher values, CO recombination is observed. Three, intermediate structures have been determined during the rebinding process., Efficient recombination occurs only above 180 K, the characteristic, temperature for the onset of protein dynamics. Rebinding is remarkably, slow because bulky residues His64 and Trp29 block important migration, pathways of the CO molecule.

About this Structure

2BLI is a Single protein structure of sequence from Physeter catodon with HEM as ligand. Structure known Active Site: AC1. Full crystallographic information is available from OCA.

Reference

Ligand migration and protein fluctuations in myoglobin mutant L29W., Nienhaus K, Ostermann A, Nienhaus GU, Parak FG, Schmidt M, Biochemistry. 2005 Apr 5;44(13):5095-105. PMID:15794647

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