| Autor: |
Berbersi, Guy A. M., Hoekman, Wuleke A., Bloemendal, Hans, Wilfried W, De Jong, Kleinschmidt, Traute, Braunitzer, Gerhard |
| Předmět: |
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| Zdroj: |
European Journal of Biochemistry; 3/15/84, Vol. 139 Issue 3, p467-479, 13p |
| Abstrakt: |
Partial amino acid sequences of six major subunits of bovine β-crystallin have been determined by automatic liquid-phase Edman degradation and the dansyl-Edman procedure, complemented by amino acid analyses of peptides. The results show that, including the previously established βBp sequence [H. P C. Driessen et al. (1981) Eur. J. Biochein. 121, 83-91], there exist at least seven primary gene products in bovine β-crystallin, which exhibit 40% or more sequence homology. Two of the gene products are completely identical except for the presence in one of them of 17 additional residues at the N terminus, possibly caused by differential splicing of the same primary RNA transcript. The rate of evolutionary change of the β chains (4% sequence change per 100 × 106 years) is about equally slow as that of α-crystallin, and the gene duplications giving rise to the different chains must have occurred very early in vertebrate evolution. The β chains can be divided into two groups, according to sequence homology and presence of deletions/insertions and C-terminal extension, on which basis a new, rational nomenclature for the β subunits is introduced. The N-terminal extensions of all β chains are very different in length and sequence, even between homologous β chains in different species. Possible explanations for this finding are discussed. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
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