Isolation and cloning of a conotoxin with a novel cysteine pattern from Conus caracteristicus.
A new conotoxin, ca16a, containing 8 cysteine residues was purified, sequenced, and cloned from a worm-hunting snail, Conus caracteristicus. This conotoxin is an extremely hydrophilic peptide comprising 34 residues, with 4 acidic and 4 basic residues. It is rich in polar Gly, Ser, and Thr residues and includes a hydroxylated Pro residue. The cysteine arrangement pattern of ca16a (-C-C-CC-C-CC-C-, designated as framework #16) is distinct from that of other known conotoxins. Furthermore, the signal peptide sequence of this conotoxin does not share any homology with those of other conotoxins. Leu residues account for almost 50% of its 20-residue signal peptide. The unique cysteine framework and signal peptide sequence of ca16a suggest that it belongs to a new conotoxin superfamily.
Yuan
Duo-Duo
DD
Institute of Protein Research, College of Life Sciences and Technology, Tongji University, 1239 Siping Road, Shanghai 200092, PR China.
Liu
Li
L
Shao
Xiao-Xia
XX
Peng
Can
C
Chi
Cheng-Wu
CW
Guo
Zhan-Yun
ZY
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D003001:Cloning, Molecular; D020916:Conotoxins / Q000096:biosynthesis / Q000302:isolation & purification*; D052078:Conus Snail / Q000737:chemistry; D003545:Cysteine / Q000032:analysis*; D008969:Molecular Sequence Data; D021382:Protein Sorting Signals / Q000235:genetics; D016415:Sequence Alignment
D020916:Conotoxins; D021382:Protein Sorting Signals; C532439:ca16a protein, Conus caracteristicus; D003545:Cysteine