1abs
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(New page: 200px<br /><applet load="1abs" size="450" color="white" frame="true" align="right" spinBox="true" caption="1abs, resolution 1.5Å" /> '''PHOTOLYSED CARBONMONO...)
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Revision as of 08:37, 20 November 2007
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PHOTOLYSED CARBONMONOXY-MYOGLOBIN AT 20 K
Overview
Myoglobin is a globular haem protein that reversibly binds ligands such as, O2 and CO. Single photons of visible light can break the covalent bond, between CO and the haem iron in carbon-monoxy-myoglobin (MbCO) and thus, form an unstable intermediate, Mb*CO, with the CO inside the protein. The, ensuing rebinding process has been extensively studied as a model for the, interplay of dynamics, structure and function in protein reactions. We, have used X-ray crystallography at liquid-helium temperatures to determine, the structure of Mb*CO to a resolution of 1.5 A. The photodissociated CO, lies on top of the haem pyrrole ring C. Comparison with the CO-bound and, unligated myoglobin structures reveals that on photodissociation of the, CO, the haem 'domes', the iron moves partially out of the haem plane, the, iron-proximal histidine bonds is compressed, the F helix is strained and, the distal histidine swings towards the outside of the ligand-binding, pocket.
About this Structure
1ABS is a Single protein structure of sequence from Physeter catodon with SO4, HEM and CMO as ligands. Full crystallographic information is available from OCA.
Reference
Crystal structure of photolysed carbonmonoxy-myoglobin., Schlichting I, Berendzen J, Phillips GN Jr, Sweet RM, Nature. 1994 Oct 27;371(6500):808-12. PMID:7935843
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