Functional expression and characterization of four novel neurotoxins from sea anemone Anthopleura sp.
The genes of four novel neurotoxins, named Hk2a, Hk7a, Hk8a, and Hk16a, were obtained from sea anemone Anthopleura sp. All four neurotoxins were composed of 47 amino acid residues and the variable residues among them were found in positions 14, 22, 25, and 37. To study their activities, the four toxins fused to the Escherichia coli thioredoxin were overexpressed by BL21 (DE3), cleaved off from the fusion partner, purified, and characterized with MALDI-TOF and CD assays. Contractile force studies of isolated SD atria indicated that rHk2a had the strongest and rHk7a the longest heart stimulation effect. Consequently, the Arg14, a highly conserved residue in various sea anemone neurotoxins, can be inferred to contribute to the duration but not the intensity of contraction-stimulating activity. Our work renders useful information to studies of sea anemone neurotoxins, especially to the clarification of the function of the disputative Arg14.
Wang
Lei
L
Department of Biochemistry, College of Life Sciences, Sun Yat-sen (Zhongshan) University, Guangzhou 510275, People's Republic of China.
Ou
Jingxing
J
Peng
Lisheng
L
Zhong
Xiaofen
X
Du
Jianyang
J
Liu
Yushan
Y
Huang
Yushan
Y
Liu
Wenhua
W
Zhang
Yuan
Y
Dong
Meiling
M
Xu
An-long
AL
D000595:Amino Acid Sequence; D000818:Animals; D019677:Artificial Gene Fusion; D001483:Base Sequence; D002942:Circular Dichroism; D018076:DNA, Complementary / Q000235:genetics; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism; D015870:Gene Expression / Q000235:genetics; D006325:Heart Atria / Q000187:drug effects; D008969:Molecular Sequence Data; D009200:Myocardial Contraction / Q000187:drug effects; D009498:Neurotoxins / Q000096:biosynthesis* / Q000737:chemistry / Q000235:genetics / Q000494:pharmacology*; D010957:Plasmids / Q000235:genetics; D017433:Protein Structure, Secondary; D051381:Rats; D011919:Rats, Inbred Strains; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis / Q000235:genetics / Q000302:isolation & purification / Q000494:pharmacology; D012615:Sea Anemones / Q000737:chemistry*; D017386:Sequence Homology, Amino Acid
D018076:DNA, Complementary; D009498:Neurotoxins; D011993:Recombinant Fusion Proteins