Molecular evolution from argininosuccinate lyase to delta-crystallin.
cDNA clones for rat argininosuccinate lyase, a urea cycle enzyme, were cloned and amino acid sequence of the enzyme was predicted. The rat enzyme is 54% identical with the yeast enzyme, which is involved in arginine biosynthesis, thereby indicating that this urea cycle enzyme evolved from the arginine biosynthetic enzyme. A striking similarity (64% identity) was found between amino acid sequences of rat argininosuccinate lyase and chicken delta-crystallin, a major structural protein of the eye lens. The gene for the rat argininosuccinate lyase was cloned and its structure was determined. This gene is a single-copy gene about 14 kilobases long and is split into 16 exons. A comparison with chicken delta-crystallin genes revealed that all introns interrupt the protein-coding regions at homologous positions. This close similarity in structural organization provides strong evidence for the view that the chicken delta 1- and delta 2-crystallin genes evolved by recruitment and duplication of the preexisting argininosuccinate lyase gene and that delta 2-crystallin is probably the direct homologue of argininosuccinate lyase.
Institute for Medical Genetics, Kumamoto University Medical School, Japan.
M
M
Mori
T
T
Matsubasa
Y
Y
Amaya
M
M
Takiguchi
D000595:Amino Acid Sequence; D000818:Animals; D001123:Argininosuccinate Lyase / Q000235:genetics*; D001483:Base Sequence; D005075:Biological Evolution; D002645:Chickens; D003459:Crystallins / Q000235:genetics*; D005796:Genes; D006801:Humans; D007527:Isoenzymes / Q000235:genetics; D008190:Lyases / Q000235:genetics*; D008969:Molecular Sequence Data; D051381:Rats; D012441:Saccharomyces cerevisiae / Q000201:enzymology / Q000235:genetics; D012689:Sequence Homology, Nucleic Acid; D012984:Software
D003459:Crystallins; D007527:Isoenzymes; D008190:Lyases; D001123:Argininosuccinate Lyase