1abs
PHOTOLYSED CARBONMONOXY-MYOGLOBIN AT 20 K
OverviewOverview
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 StructureAbout this Structure
1ABS is a Single protein structure of sequence from Physeter catodon. Full crystallographic information is available from OCA.
ReferenceReference
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 Page seeded by OCA on Fri May 2 10:04:49 2008