2uyd
From Proteopedia
CRYSTAL STRUCTURE OF THE SMHASA MUTANT H83A
Overview
Heme carrier HasA has a unique type of histidine/tyrosine heme iron ligation in which the iron ion is in a thermally driven two spin state equilibrium. We recently suggested that the H-bonding between Y75 and the invariantly conserved residue H83 modulates the strength of the Fe-Y75 bond. To unravel the role of H83, we characterize the iron ligation and the electronic properties of both wild type and H83A mutant by a variety of spectroscopic techniques. While H83 in wild type modulates the strength of the Tyr-iron bond, its removal causes detachment of the tyrosine ligand, thus giving rise to a series of pH dependent equilibria among species with different axial ligation. The five coordinated species detected at physiological pH may represent a possible intermediate of the heme transfer mechanism to the receptor.
About this Structure
2UYD is a Single protein structure of sequence from Serratia marcescens. Full crystallographic information is available from OCA.
Reference
Deciphering the structural role of histidine 83 for heme binding in hemophore HasA., Caillet-Saguy C, Turano P, Piccioli M, Lukat-Rodgers GS, Czjzek M, Guigliarelli B, Izadi-Pruneyre N, Rodgers KR, Delepierre M, Lecroisey A, J Biol Chem. 2007 Dec 27;. PMID:18162469 Page seeded by OCA on Sun May 4 17:48:34 2008
