The crystal structure of myoglobin. VI. Seal myoglobin

• Published in: Proceedings of the Royal Society of London. Series A. Mathematical and Physical Sciences
• Format: Article in Journal/Newspaper
• Language: English
• Published: The Royal Society 1960
• Subjects: common seal; Phoca vitulina; Sperm whale
• Online Access: http://dx.doi.org/10.1098/rspa.1960.0181; https://royalsocietypublishing.org/doi/pdf/10.1098/rspa.1960.0181

Myoglobin from the common seal ( Phoca vitulina ) when crystallized from ammonium sulphate forms monoclinic crystals with space group the unit cell, a = 57·9Å, b = 29·6Å, c = 106·4Å, β = 102°15', contains four molecules. The method of isomorphous replacement has been used in an investigation of the centrosymmetric b -axis projection in which it has been possible to determine signs for nearly all the h0l reflexions having spacings greater than 4Å. Three independent heavy-atom derivatives were employed and the signs so determined have been used to compute a map of the electron density projected on the (010) plane. This projection has been interpreted in terms of the molecule of sperm-whale myoglobin, as deduced by Bodo, Dintzis, Kendrew & Wyckoff (1959) from a three-dimensional Fourier synthesis to 6Å resolution. The results of the interpretation show that the two myoglobin molecules are very similar in form (tertiary structure) in spite of the differences in their amino-acid composition. The relative orientation of the two unit cells with respect to the myoglobin molecule is given and a comparison is made of the positions of the heavy atoms in each molecule.