Myoglobin, function structure

Important novel information has thus been obtained for the specific biological function of those molecules, but disappointingly few general lessons have been learned that are relevant for other membrane-bound proteins with different biological functions. In that respect the situation is similar to the failure of the structure of myoglobin to provide general principles for the construction of soluble protein molecules as described in Chapter 2. 

Special Focus Hemoglobin and Myoglobin— Paradigms of Protein Structure and Function... 

Sequence conservation is, in general, much weaker than structural conservation. There are proteins, which are clearly not related in sequence but are closely related in 3D-stmcture and fold, like heamoglobin and myoglobin, which have similar functions. In many proteins, fold elements like 4-helical bundles are repeated. Classifications of known structural folds of proteins are organized in the SCOP or CATH database see e.g., http //scop.mrc-lmb.cam.ac.uk/scop/. 

H. Frauenfelder, B.H. McMahon, R.H. Austin, K. Chu, and J.T. Groves, The role of structure, energy landscape, dynamics, and allostery in the enzymatic function of myoglobin. Proc. Natl. Acad. Sci. 98, 2370(2001). 

Despite all these studies of proteins and synthetic models, many essential aspects of the function of myoglobin and hemoglobin, e.g. the way the protein controls the binding of ligands (02, CO, and NO), the precise structure of the Fe-ligand bonds and the structure-spin-energy relationships at the active center, are a topic of debate [2]. 

Myoglobin in many respects is the prototypical example of the larger family of heme containing proteins and enzymes that vary in function from the relatively simple process of reversible binding of an electron to the activation of dioxygen for substrate hydroxylation. The relationship between members of this family of proteins is not based simply on structural similarities but on similarities in chemical reactivity as well. As the structure of myoglobin is relatively simple compared to other heme proteins and as it was the first for which the three-dimensional... 

The x-ray crystallographic analysis of protein structures is a remarkably successful technique. Since the publication of the first protein structure, that of myoglobin in 1958, many other protein structures have been determined. The resulting structural details often approaching atomic level have led to great insights into enzyme catalysis, hormone function, the organisation of the immune system, the molecular architecture of virus particles and protein synthesis. Why then should such an apparently successful technique need synchrotron radiation ... 

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