Molecular palaeogenetics: Amino acid sequence homology in ribonuclease and lysozyme
1967; Pergamon Press; Volume: 23; Issue: 2 Linguagem: Inglês
10.1016/0010-406x(67)90394-5
ISSN1879-3029
Autores Tópico(s)Blood groups and transfusion
Resumo1. Three approaches are employed, together with appropriate statistical methods, to test the hypothesis that bovine pancreatic ribonuclease and chicken egg-white lysozyme are homologous proteins. 2. All three methods (which are partially correlated) give probabilities ranging from 0·01 to 0·0008 that such a set of similarities could have arisen entirely at random. 3. About 10 per cent of the original “protogene” remains as a “molecular fossil” in the desoxyribonucleotide sequence coding lysozyme and RNAse. 4. Several pieces of evidence, including a curious heterogeneity in the purine-pyrimidine distribution between the first two and the third nucleotides in the messenger codon equivalents, suggest that the divergence of RNAse and lysozyme took place very early in the evolution of living organisms, perhaps near the origin of life itself. 5. A possible homology exists between a decapeptide sequence of 'phage T-4 lysozyme and hen ovolysozyme. 6. The peculiar amino acid composition of goose ovolysozyme can be explained by postulating a dirty deletion in the middle of the ancestral anserine lysozyme cistron; this has resulted in a single-letter coding frame shift, which “scrambles” the C-terminal half of goose lysozyme.
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