Human 27-kDa calbindin complementary DNA sequence. Evolutionary and functional implications.
Human 27-kDa calbindin cDNA clones were selected by antibody screening from lambda gt11 brain libraries. The sequence revealed an open reading frame coding for a protein of 261 amino acids, containing four active calcium-binding domains, and two modified domains that had presumably lost their calcium-binding capability. Comparison with chick and bovine calbindins showed that the protein was highly conserved in evolution (evolutionary rate: 0.3 x 10(-9) amino acid-1 year-1) and that active and inactive domains were equally conserved. From the data we postulate that calbindin has an important physiological function involving protein--protein interactions. Comparison of calcium-binding domains from various proteins suggested that all members of the troponin C superfamily derive from a common two-domained ancestor, but that duplications leading to calbindin and to the four-domained calcium-binding proteins took place independently on different branches of the evolutionary tree. Preliminary data showed that another calcium-binding protein, homologous to calbindin, is present in the brain and encoded by a different gene.
Institut de Recherche Interdisciplinaire en Biologie Humaine et Nucléaire, Université Libre de Bruxelles, Belgium.
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M
Parmentier
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DE
Lawson
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G
Vassart
D000595:Amino Acid Sequence; D000818:Animals; D000906:Antibodies; D001483:Base Sequence; D005075:Biological Evolution; D002417:Cattle; D002645:Chickens; D003001:Cloning, Molecular; D004247:DNA / Q000378:metabolism*; D006801:Humans; D008969:Molecular Sequence Data; D064030:S100 Calcium Binding Protein G / Q000235:genetics*; D012689:Sequence Homology, Nucleic Acid; D014336:Troponin / Q000235:genetics; D019209:Troponin C
D000906:Antibodies; D064030:S100 Calcium Binding Protein G; D014336:Troponin; D019209:Troponin C; D004247:DNA