Cloning and structural analysis of alpha-latroinsectotoxin cDNA. Abundance of ankyrin-like repeats.
alpha-Latroinsectotoxin (alpha-LIT), purified from venom glands of the black widow spider Latrodectus mactans tredecimguttatus, is a presynaptic neurotoxin selective only for insects. A cDNA encoding the putative alpha-LIT precursor was isolated from a spider venom gland cDNA library. The cDNA contains a 4236-base-pair open reading frame corresponding to a 157826-Da protein composed of 1411 amino acids. The mature alpha-LIT, with molecular mass approximately 130 kDa, is probably derived from double processing in the N-terminal and C-terminal regions of the primary translation product. The structure region, extending over residues 464-1176, is composed almost entirely of ankyrin-like repeats which represent a motif also found in the alpha-latrotoxin (alpha-LTX), which has selective action on vertebrates. Total alignment of the alpha-LIT and alpha-LTX amino acid sequences reveals an overall similarity of 34.1%. Strong sequence divergence is observed in analogous cysteine-rich regions situated within the ankyrin-repeat domains of both alpha-LIT and alpha-LTX.
Kiyatkin
N
N
Shemyakin Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow.
Dulubova
I
I
Grishin
E
E
D000595:Amino Acid Sequence; D000818:Animals; D017487:Ankyrins / Q000235:genetics*; D001483:Base Sequence; D001740:Black Widow Spider; D003001:Cloning, Molecular; D004247:DNA; D008969:Molecular Sequence Data; D012091:Repetitive Sequences, Nucleic Acid; D017386:Sequence Homology, Amino Acid; D013111:Spider Venoms / Q000235:genetics*
D017487:Ankyrins; D013111:Spider Venoms; C074805:latroinsectotoxin; D004247:DNA