3mba

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spinqualitylabelsall models 3mba, resolution 2.0Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image

APLYSIA LIMACINA MYOGLOBIN. CRYSTALLOGRAPHIC ANALYSIS AT 1.6 ANGSTROMS RESOLUTION

Overview

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 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.

Reference

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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