1b0b

From Proteopedia

Revision as of 08:04, 20 March 2008

HEMOGLOBIN I FROM THE CLAM LUCINA PECTINATA, CYANIDE COMPLEX AT 100 KELVIN

Overview

The x-ray crystal structures of the cyanide derivative of Lucina pectinata monomeric hemoglobin I (L. pectinata HbI) and sperm whale (Physeter catodon) myoglobin (Mb), generally taken as reference models for monomeric hemoproteins carrying hydrogen sulfide and oxygen, respectively, have been determined at 1.9 A (R-factor = 0. 184), and 1.8 A (R-factor = 0.181) resolution, respectively, at room temperature (lambda = 1.542 A). Moreover, the x-ray crystal structure of the L. pectinata HbI:cyanide derivative has been studied at 1.4-A resolution (R-factor = 0.118) and 100 K (on a synchrotron source lambda = 0.998 A). At room temperature, the cyanide ligand is roughly parallel to the heme plane of L. pectinata HbI, being located approximately 2.5 A from the iron atom. On the other hand, the crystal structure of the L. pectinata HbI:cyanide derivative at 100 K shows that the diatomic ligand is coordinated to the iron atom in an orientation almost perpendicular to the heme (the Fe-C distance being 1.95 A), adopting a coordination geometry strictly reminescent of that observed in sperm whale Mb, at room temperature. The unusual cyanide distal site orientation observed in L. pectinata HbI, at room temperature, may reflect reduction of the heme Fe(III) atom induced by free radical species during x-ray data collection using Cu Kalpha radiation.

About this Structure

1B0B is a Single protein structure of sequence from Lucina pectinata. Full crystallographic information is available from OCA.

Reference

Cyanide binding to Lucina pectinata hemoglobin I and to sperm whale myoglobin: an x-ray crystallographic study., Bolognesi M, Rosano C, Losso R, Borassi A, Rizzi M, Wittenberg JB, Boffi A, Ascenzi P, Biophys J. 1999 Aug;77(2):1093-9. PMID:10423453

Page seeded by OCA on Thu Mar 20 10:04:36 2008