Functional and Structural Comparisons of Acidic and Basic Plant Non-Specific Lipid Transfer Protein
| Autor: | Chen, Hsueh-Chun, 陳學群 |
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| Rok vydání: | 2013 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 101 Palnt nonspecific lipid transfer proteins (nsLTPs) are small and stable proteins, which are classified into two subfamilies by molecular weight: nsLTP1 (9 kDa) and nsLTP2 (7 kDa). Currently, nsLTPs are known to have the ability to bind and transfer lipid between membranes, inhibit α-amylase activity, inhibit protease activity and display antimicrobial activity. Recently, an anther-specific acidic nsLTP (AAtLTP) has been found in Arabidopsis thaliana, while its biophysical and biochemical properties is still unknown. Therefore, in this study, we focused on structural and functional properties of AAtLTP and compared these results with the basic nsLTP (LTP2). By circular dichroism, the secondary structure of AAtLTP and LTP2 are very different, but both exhibited strong stabilities on high temperature (up to 80 ˚C) and broad pH (pH 3 to pH 13) range. On the other hand, some tests were performed to discover the biological function of AAtLTP. We found that AAtLTP and LTP2 both could not inhibit α-amylase and trypsin enzyme activities. In anti-microbial experiments, LTP2 exhibited good anti-bacterial and anti-fungal activities, against Acinetobacter baumanni and Candida albicans, but AAtLTP doesn’t have the anti-microbial ability. Moreover, the fluorescence binding assay was also used to further investigate the lipid binding abilities of nsLTPs. The results showed that LTP2 could bind to fatty acid, sterol and ρ-coumaric acid while AAtLTP could only bind to ρ-coumaric acid but with higher binding affinity than LTP2. The AAtLTP can bind ρ-coumaric acid, the lipid molecule on pollen surface, implying that this acidic nsLTP is potentially involved in the anther development. In this work, we investigated the biophysical properties and biological characters of AAtLTP, and the lipid binding selectivity and compared these results with basic nsLTP2 to further insight into the relationship between function and structure of plant LTP. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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