Molecular cloning of two toxic phospholipases A2 from the crown-of-thorns starfish Acanthaster planci venom.
The full-length cDNAs encoding two toxic phospholipases A2 (AP-PLA2-I and -II) from the crown-of-thorns starfish Acanthaster planci venom were individually cloned by RT-PCR, 3'RACE and 5'RACE. In common with both AP-PLA2s, the precursor protein is composed of a signal peptide, a propeptide and a mature protein (136 and 135 residues for AP-PLA2-I and -II, respectively). The four motifs (Ca2+-binding loop, Ca2+-binding site, active site and catalytic network) characteristic of groups I and II PLA2s are well conserved in both AP-PLA2s. In addition to this, the presence of the elapid and pancreatic loops and the involvement of a propeptide in the precursors suggested that AP-PLA2s are highly analogous to the group IB PLA2s. However, when compared to the amino acid sequence of bovine pancreatic PLA2, the representative group IB PLA2, AP-PLA2s require some amino acid insertions and deletions in the region 76-100, as previously observed for the starfish Asterina pectinifera PLA2s. Furthermore, the phylogenetic tree made clearly demonstrated that AP-PLA2s and A. pectinifera PLA2s are distinguishable from the group IB PLA2s as well as other PLA2s, being classified into a new group.
Ota
Eiji
E
Department of Food Science and Technology, Tokyo University of Marine Science and Technology, Konan-4, Minato-ku, Tokyo 108-8477, Japan.
Nagai
Hiroshi
H
Nagashima
Yuji
Y
Shiomi
Kazuo
K
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D001665:Binding Sites; D002118:Calcium / Q000378:metabolism; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000235:genetics; D008387:Marine Toxins / Q000235:genetics*; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000378:metabolism; D010741:Phospholipases A / Q000235:genetics*; D054467:Phospholipases A2; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017386:Sequence Homology, Amino Acid; D013215:Starfish / Q000235:genetics*
D018076:DNA, Complementary; D008387:Marine Toxins; D010446:Peptide Fragments; D010741:Phospholipases A; D054467:Phospholipases A2; D002118:Calcium