1j3y

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Revision as of 11:03, 8 November 2007

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spinqualitylabelsall models 1j3y, resolution 1.55Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image

Direct observation of photolysis-induced tertiary structural changes in human hemoglobin; Crystal structure of alpha(Fe)-beta(Ni) hemoglobin (laser photolysed)

Overview

Human Hb, an alpha2beta2 tetrameric oxygen transport protein that switches, from a T (tense) to an R (relaxed) quaternary structure during, oxygenation, has long served as a model for studying protein allostery in, general. Time-resolved spectroscopic measurements after photodissociation, of CO-liganded Hb have played a central role in exploring both protein, dynamical responses and molecular cooperativity, but the direct, visualization and the structural consequences of photodeligation have not, yet been reported. Here we present an x-ray study of structural changes, induced by photodissociation of half-liganded T-state and fully liganded, R-state human Hb at cryogenic temperatures (25-35 K). On photodissociation, of CO, structural changes involving the heme and the F-helix are more, marked in the alpha subunit than in the beta subunit, and more subtle in, the R state than in the T state. Photodeligation causes a significant, sliding motion of the T-state beta heme. Our results establish that the, structural basis of the low affinity of the T state is radically different, between the subunits, because of differences in the packing and chemical, tension at the hemes.

About this Structure

1J3Y is a Protein complex structure of sequences from Homo sapiens with HEM, CMO, HNI and 2FU as ligands. Full crystallographic information is available from OCA.

Reference

Direct observation of photolysis-induced tertiary structural changes in hemoglobin., Adachi S, Park SY, Tame JR, Shiro Y, Shibayama N, Proc Natl Acad Sci U S A. 2003 Jun 10;100(12):7039-44. Epub 2003 May 28. PMID:12773618

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