Referenced in: none

Automatically associated channels: ClC4

Title: Functional expression and characterization of an acidic actinoporin from sea anemone Sagartia rosea.

Authors: Xiaoyu Jiang, Huiping Chen, Wenli Yang, Yun Liu, Wei Liu, Jianwen Wei, Hongbin Tu, Xiaojin Xie, Lei Wang, Anlong Xu

Journal, date & volume: Biochem. Biophys. Res. Commun., 2003 Dec 19 , 312, 562-70

PubMed link: http://www.ncbi.nlm.nih.gov/pubmed/14680802

Abstract
Src I is the first reported acidic actinoporin from sea anemone Sagartia rosea with a pI value of 4.8 and comprises 13.9% alpha-helix, 65.1% beta-sheet, and 18.2% random coil. For structure-function studies, Src I was expressed in Escherichia coli as a cleavable fusion protein. Recombinant Src I exhibited obviously hemolytic activity, but the fusion protein Trx-Src I almost lost its hemolytic activity, suggesting the importance of the N-terminal amphiphilic alpha-helix for its functional activity. The cytotoxic effects of Src I depending on the toxin concentration and incubation time were also observed on cultured cells. Among five cell lines: NIH/3T3, U251, NSCLC, BEL-7402, and BGC-823, NSCLC was the most sensitive cells with ID(50) 2.8 microg/ml and BGC-823 was the least sensitive cells with ID(50) 7.4 microg/ml. After incubated with lipid SUVs, such as SM-SUVs and SM/PC-SUVs, the hemolytic activity of Src I was inhibited to some extent. When incubated with calcein-entrapped lipid LUVs, such as SM-LUVs, SM/PC-LUVs, and SM/PG-LUVs, Src I induced release of entrapped calcein. According to the interaction with lipid vesicles, we proposed that it was the membrane matrix made up of phospholipids, not a particular phospholipid that facilitates Src I to react properly.