Primary Citation of Related Structures: 1MBA, 3MBA, 4MBA
PubMed Abstract:
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 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.
Related Citations:
Aplysia Limacina Myoglobin. Molecular Bases for Ligand Binding and Reversible Unfolding Bolognesi, M., Gatti, G., Guanziroli, M.G., Mattevi, A., Onesti, S., Coda, A., Ascenzi, P., Brunori, M. () To be published --: --
Crystal Structure of Ferric Aplysia Limacina Myoglobin at 2.0 Angstroms Resolution Bolognesi, M., Coda, A., Gatti, G., Ascenzi, P., Brunori, M. (1985) J Mol Biol 183: 113
Reactivity of Ferric Aplysia and Sperm Whale Myoglobins Towards Imidazole. X-Ray and Binding Study Bolognesi, M., Cannillo, E., Ascenzi, P., Giacometti, G.M., Merli, A., Brunori, M. (1982) J Mol Biol 158: 305
The Structure of Aplysia Limacina Myoglobin at 3.6 Angstroms Resolution Bolognesi, M., Cannillo, E., Oberti, R., Rossi, G., Ungaretti, L. (1978) Acta Crystallogr A Cryst Phys Diffr Theor Gen Crystallogr 34: 62
The Crystal Structure of met-Myoglobin from Aplysia Limacina at 5 Angstroms Resolution Ungaretti, L., Bolognesi, M., Cannillo, E., Oberti, R., Rossi, G. (1978) Acta Crystallogr B 34: 3658
Crystallization and Preliminary X-Ray Diffraction Studies on met-Myoglobin from Aplysia Limacina Blundell, T.L., Brunori, M., Curti, B., Bolognesi, M., Coda, A., Fumagalli, M., Ungaretti, L. (1975) J Mol Biol 97: 665
The Amino Acid Sequence of Myoglobin from the Mollusc Aplysia Limacina Tentori, L., Vivaldi, G., Carta, S., Marinucci, M., Massa, A., Antonini, E., Brunori, M. (1973) Int J Pept Protein Res 5: 187
Organizational Affiliation:
Dipartimento di Genetica e Microbiologia, Università di Pavia, Italy.
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