1v4u

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spinqualitylabelsall models 1v4u, resolution 2.00Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image

Crystal structure of bluefin tuna carbonmonoxy-hemoglobin

Overview

The crystal structure of hemoglobin has been known for several decades, yet various features of the molecule remain unexplained or controversial. Several animal hemoglobins have properties that cannot be readily explained in terms of their amino acid sequence and known atomic models of hemoglobin. Among these, fish hemoglobins are well known for their widely varying interactions with heterotropic effector molecules and pH sensitivity. Some fish hemoglobins are almost completely insensitive to pH (within physiological limits), whereas others show extremely low oxygen affinity under acid conditions, a phenomenon called the Root effect. X-ray crystal structures of Root effect hemoglobins have not, to date, provided convincing explanations of this effect. Sequence alignments have signally failed to pinpoint the residues involved, and site-directed mutagenesis has not yielded a human hemoglobin variant with this property. We have solved the crystal structure of tuna hemoglobin in the deoxy form at low and moderate pH and in the presence of carbon monoxide at high pH. A comparison of these models shows clear evidence for novel mechanisms of pH-dependent control of ligand affinity.

About this Structure

1V4U is a Protein complex structure of sequences from Thunnus thynnus with , and as ligands. Full crystallographic information is available from OCA.

Reference

Novel mechanisms of pH sensitivity in tuna hemoglobin: a structural explanation of the root effect., Yokoyama T, Chong KT, Miyazaki G, Morimoto H, Shih DT, Unzai S, Tame JR, Park SY, J Biol Chem. 2004 Jul 2;279(27):28632-40. Epub 2004 Apr 26. PMID:15117955

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