Taiwan cobra (Naja naja atra) cardiotoxins, are composed of 60 amino acids and structurally stabilized by four disulfide bonds to form three loops structure. Cardiotoxins induced hemolysis of red blood cells and form a channel-like structure in inducing phospholipid vesicles leakage. The aim of the present study is to explore the events affect the membrane-damaging activity of cardiotoxin 3 (CTX3). Depletion of cholesterol in membrane of red blood cells using methyl-£]-cyclodextrin (M£]CD) enhanced the hemolytic activity of CTX3. Expectedly, CTX3 showed a low binding capability and lower membrane-damaging activity toward phospholipid vesicles containing cholesterol. Guanidinated of lysine residues and selective trinitrobenzoylation (TNP) at N-terminus of guanidinated CTX3 (Gu-CTX3) insignificantly altered binding capability and membrane-damaging activity of CTX3 regardless of phospholipid vesicles containing cholesterol. The binding of CTX3, Gu-CTX3 and TNP-Gu-CTX3 with phospholipid vesicles was reduced by increasing NaCl concentration. Consistent with these observations, membrane-damaging activity of CTX3, Gu-CTX3 and TNP-Gu-CTX3 were also decreased with increasing NaCl concentration. Unlike that of Gu-CTX3 and TNP-Gu-CTX3, membrane-damaging activity and membrane-induced oligomerization of CTX3 was completely abolished by 1 M NaCl. Fourier transform infrared spectroscopy indicated that CTX3, Gu-CTX3 and TNP-Gu-CTX3 adopted different conformation on binding with phospholipid vesicles and phospholipid/cholesterol vesicles. Taken together, our data indicate that membrane-bound conformation of CTX3 is affected by cholesterol and guanidination of lysine residues.
| Identifer | oai:union.ndltd.org:NSYSU/oai:NSYSU:etd-0630109-162046 |
| Date | 30 June 2009 |
| Creators | Huang, Jyun-yan |
| Contributors | none, Long-Sen Chang, none |
| Publisher | NSYSU |
| Source Sets | NSYSU Electronic Thesis and Dissertation Archive |
| Language | Cholon |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | http://etd.lib.nsysu.edu.tw/ETD-db/ETD-search/view_etd?URN=etd-0630109-162046 |
| Rights | off_campus_withheld, Copyright information available at source archive |
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