Haemoglobin amino acid sequences

Globular proteins were much more difficult to prepare in an ordered form. In 1934, Bernal and Crowfoot (Hodgkin) found, that crystals were better preserved if they were kept in contact with their mother liquor sealed in thin-walled glass capillaries. By the early 1940s crystal classes and unit cell dimensions had been determined for insulin, horse haemoglobin, RNAase, pepsin, and chymotrypsin. Complete resolution of the structures required identification of the crystal axes and some knowledge of the amino acid sequence of the protein—requirements which could not be met until the 1950s. 

P13. Perutz, M. F., Kendrew, J. C., and Watson, H. C., Structure and function of haemoglobin. II. Some relations between polypeptide chain configuration and amino acid sequence. J. Mol. Biol. 13, 669-678 (1965). 

Normal haemoglobin has a Pjg of 3.4 kPa and n of 2.6-3.0 at pH 7.4. Values of both P50 and n are affected by genetic abnormalities in haemoglobin synthesis that alter the amino acid sequence. Over 190 such variants are known, with a wide range of Pjg and n values. 

Nash, A.R., Fisher, W.K., and Thompson, E.O.R, Haemoglobins of the shark, Heterodontus portusjacksoni. II. Amino acid sequence of the a-chain, Aust. J. Biol. Sci., 29, 73-97,1976. Nelson, G.J., Origin and diversification of teleostean fishes, Ann. NY Acad. Sci., 167,18-30,1969. Nelson, G.J., Outline of a theory of comparative biology, Syst. Zool., 19, 373-384, 1970. Nelson, G.J., Cladism as a philosophy of classification, Syst. Zool., 20, 373-376, 1971. Nelson, G., Ancient perspectives and influence in the theoretical systematics of a bold fisherman, Linnean, Special issue No. 2, 9-23, 2000. 

The molecular weights of Vertebrate haemoglobins are situated around 65,000-68,000. The molecules are apparently made up of two systems of three peptide chains. The N-terminal amino acid sequence of a number of haemoglobins is given in Table XXIV. There would appear to be a common basic chain in all cases. 

Over 300 variations from the amino acid sequence of normal human adult haemoglobin... 

Table 2. Amino acid sequence of human haemoglobin and sperm whale myoglobin...

Figure C2.5.1. The 3D native stmcture of haemoglobin visualized using RasMol 2.6 [8], The linear sequence of amino acids of haemoglobin is given below tire figure.

Biochemical evolution refers to changes over geologic time of the fundamental composition of organic components—e.g., the sequence of amino acids in protein molecules. The best documented example of biochemical evolution is that of the respiratory pigment haemoglobin, and the relation of its evolution to the fossil record has been summarized recently (58). Many of the monographs on comparative biochemistry have discussed biochemical evolution (59, 60, 61), and the reader is... 

However, what is confusing to the analytical scientist is much less so for the cell, whose precision in distinguishing tiny variations in molecules whose weight may be in the order of millions is as great as the analytical power of the best of computers. The classical case is that of haemoglobin, a blood protein which contains some three hundred amino acids changing the sequence of... 

Fig. 80. (Perutz). Sequence of amino acid residues in a small segment of one of the polypeptide diain of haemoglobin.

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