3mba
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APLYSIA LIMACINA MYOGLOBIN. CRYSTALLOGRAPHIC ANALYSIS AT 1.6 ANGSTROMS RESOLUTION
OverviewOverview
The crystal structure of the ferric form of myoglobin from the mollusc, Aplysia limacina has been refined at 1.6 A resolution, by restrained, crystallographic refinement methods. The crystallographic R-factor is, 0.19. The tertiary structure of the molecule conforms to the common globin, fold, consisting of eight alpha-helices. The N-terminal helix A and helix, G deviate significantly from linearity. The distal residue is recognized, as Val63 (E7), which, however, does not contact the heme directly., Moreover the sixth (distal) co-ordination position of heme iron is not, occupied by a water molecule at neutrality, i.e. below the acid-alkaline, transition point of A. limacina myoglobin. The heme group sits in its, crevice in the conventional orientation and no signs of heme isomerism are, evident. The iron atom is 0.26 A out of the porphyrin plane, with a mean, Fe-N (porphyrin) distance of 2.01 A. The co-ordination bond to the, proximal histidine has a length of 2.05 A, and forms an angle of 4 degrees, with the heme normal. A plane containing the imidazole ring of the, proximal His intersects the heme at an angle of 29 degrees with the, (porphyrin) 4N-2N direction. Inspection of the structure of pH 9.0, indicates that a hydroxyl ion is bound to the Fe sixth co-ordination, position.
About this StructureAbout this Structure
3MBA is a Single protein structure of sequence from Aplysia limacina with F, ACE and HEM as ligands. Full crystallographic information is available from OCA.
ReferenceReference
Aplysia limacina myoglobin. Crystallographic analysis at 1.6 A resolution., Bolognesi M, Onesti S, Gatti G, Coda A, Ascenzi P, Brunori M, J Mol Biol. 1989 Feb 5;205(3):529-44. PMID:2926816
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