Expression and Purification of Sperm Whale Myoglobin

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.

Download Full-text

Immunochemistry of sperm-whale myoglobin

Biochimica et Biophysica Acta (BBA) - Protein Structure ◽

10.1016/0005-2795(73)90262-6 ◽

1973 ◽

Vol 328 (2) ◽

pp. 289-302 ◽

Cited By ~ 78

Author(s):

J. Koketsu ◽

M.Z. Atassi

Keyword(s):

Sperm Whale ◽

Sperm Whale Myoglobin

Download Full-text

The Amino-Acid Sequence of Sperm Whale Myoglobin: Chemical Studies

Nature ◽

10.1038/190663a0 ◽

1961 ◽

Vol 190 (4777) ◽

pp. 663-665 ◽

Cited By ~ 92

Author(s):

A. B. EDMUNDSON ◽

C. H. W. HIRS

Keyword(s):

Amino Acid ◽

Amino Acid Sequence ◽

Sperm Whale ◽

Chemical Studies ◽

Sperm Whale Myoglobin

Download Full-text

The structure of haemoglobin. IX. A three-dimensional Fourier synthesis at 5.5 Å resolution: description of the structure

Proceedings of the Royal Society of London Series A - Mathematical and Physical Sciences ◽

10.1098/rspa.1962.0002 ◽

1962 ◽

Vol 265 (1321) ◽

pp. 161-187 ◽

Cited By ~ 70

Keyword(s):

Tertiary Structure ◽

Three Dimensional ◽

Sperm Whale ◽

Anomalous Scattering ◽

Fourier Synthesis ◽

Human Haemoglobin ◽

Contour Maps ◽

To Come ◽

Polypeptide Chains ◽

Sperm Whale Myoglobin

The electron density distribution in the unit cell is calculated at intervals of approximately 2Å and plotted in a series of sections parallel to (010). The contour maps show that haemoglobin consists of four subunits in a tetrahedral array. The subunits are identical in pairs in accordance with the twofold symmetry of the molecule. The two pairs are very similar in structure, and the members of each pair closely resemble the molecule of sperm-whale myoglobin. The four haem groups lie in separate pockets at the surface of the molecule. The positions of the iron atoms are confirmed by comparison of observed and calculated anomalous scattering effects, which also serve to determine the absolute configuration of the molecule. The four subunits found by X-ray analysis correspond to the four polypeptide chains into which haemoglobin can be divided by chemical methods. In horse haemoglobin the amino acid sequence within these chains is still partly unknown, but in human haemoglobin it has already been determined. Comparison of this sequence with the tertiary structure of the chains as now revealed in horse haemoglobin and with the atomic model of sperm-whale myoglobin recently obtained by Kendrew and his collaborators shows many interesting relations. Prolines appear to come where the chains turn corners or where their configuration is known to be non-helical. On the other hand, the chains also have corners which contain no proline. Certain residues appear to be structurally vital, because they appear in identical positions in myoglobin and in the two chains of haemoglobin, while in other parts of the molecule a wide variety of different side-chains appears to be allowed.

Download Full-text