DIRECT EVALUATION OF EFFECTS OF FATTY-ACID UNSATURATION ON THE THERMAL-PROPERTIES OF PHOTOSYNTHETIC ACTIVITIES, AS STUDIED BY MUTATION AND TRANSFORMATION OF SYNECHOCYSTIS PCC6803
DIRECT EVALUATION OF EFFECTS OF FATTY-ACID UNSATURATION ON THE THERMAL-PROPERTIES OF PHOTOSYNTHETIC ACTIVITIES, AS STUDIED BY MUTATION AND TRANSFORMATION OF SYNECHOCYSTIS PCC6803
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DOI：
10.1093/oxfordjournals.pcp.a078065
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发表时间：
1991-03-01
影响因子：
4.9
通讯作者：
MURATA, N
中科院分区：
文献类型：
--
作者：
GOMBOS, Z;WADA, H;MURATA, N
从蓝细菌聚胞菌PCC6803分离的类囊体膜的甘油脂除了饱和C16和单烯C18脂肪酸外，还含有高水平的二烯和三烯C18脂肪酸。该蓝藻的突变体Fad12在δ -12位置的C18脂肪酸去饱和缺陷，其类囊体膜缺乏三烯酸，含有非常低水平的二烯酸。Fad12的一个衍生菌株（Fad12/desA）在δ -12位点转化了一个去饱和基因，完全恢复了类囊体膜甘油脂中脂肪酸的去饱和能力。将突变体和转化体的光合活性的热特性与野生型菌株进行了比较。尽管野生型、Fad12和Fad12/desA菌株之间的脂肪酸不饱和程度存在很大差异，但在光合作用的温度依赖性以及光合作用、光系统II和光系统I活性的热稳定性方面均未发现显著差异。这些结果表明，类囊体膜中脂质的三烯酸和二烯酸不影响上述光合作用的热性质。
Glycerolipids of thylakoid membranes isolated from the cyanobacterium Synechocytis PCC6803 contained high levels of dienoic and trienoic C18 fatty acids, in addition to saturated C16 and monoenoic C18 fatty acids. A mutant (Fad12) of this cyanobacterium was defective in the desaturation of C18 fatty acids at the DELTA-12 position, and its thylakoid membranes lacked trienoic acids and contained a very reduced level of dienoic acids. A derivative strain of Fad12 (Fad12/desA), which had been transformed with a gene for desaturation at the DELTA-12 position, fully recovered the ability to desaturate the fatty acids in the glycerolipids of thylakoid membranes. The thermal properties of the photosynthetic activities of the mutant and the transformant were compared with those of the wild-type strain. Despite great diversity in the extent of unsaturation of fatty acids between the wild-type, Fad12, and Fad12/desA strains, no significant differences were found either in the temperature dependence of photosynthesis or in the heat stability of photosynthetic, photosystem II and photosystem I activities. These results demonstrate that the trienoic fatty acids and, probably, the dienoic acids of the lipids in the thylakoid membrane do not affect the thermal properties of the above-mentioned activities of photosynthesis.