Constitutive expression of a small heat‐shock protein confers cellular thermotolerance and thermal protection to the photosynthetic apparatus in cyanobacteria
Constitutive expression of a small heat‐shock protein confers cellular thermotolerance and thermal protection to the photosynthetic apparatus in cyanobacteria
复制标题
DOI：
10.1016/s0014-5793(00)02097-4
复制
发表时间：
2000-10
期刊：
影响因子：
3.5
通讯作者：
Hitoshi Nakamoto;N. Suzuki;S. Roy
中科院分区：
文献类型：
--
作者：
Hitoshi Nakamoto;N. Suzuki;S. Roy
研究了一种小热休克蛋白（Hsp）在蓝藻耐热性获得中的作用。在tac启动子的控制下，用含有vulcanus Synechococcus的hspA基因编码序列的表达载体转染PCC 7942。本构表达HspA的转化体在光照下从30℃转移到50℃时，与参考菌株相比，表现出更高的活力。在黑暗条件下进行热休克时，参考菌株的存活率大大提高，接近于光条件下热休克后表达HspA的菌株的存活率。HspA的表达增加了光系统II （PS II）的耐热性，保护藻蓝蛋白免受热诱导的光漂白。我们的研究结果表明，HspA在改善热应激期间光的有害影响方面发挥了核心作用，并确定了体内小Hsp的可能作用位点是PS II复合体和光收集藻胆体。
The role of a small heat-shock protein (Hsp) in the acquisition of thermotolerance in cyanobacteria was investigated. Synechococcus sp. PCC 7942 was transformed with an expression vector carrying the coding sequence of the hspA gene encoding a small heat-shock protein from Synechococcus vulcanus under the control of the tac promoter. The transformant which was shown to constitutively express HspA displayed improved viability compared with the reference strain upon transfer from 30 to 50°C in the light. When the heat shock was given in darkness, the survival rate in the reference strain increased greatly, approaching a level similar to that for the HspA expressing strain after heat shock in the light. Expression of HspA increased thermal resistance of photosystem II (PS II) and protected phycocyanin from heat-induced photobleaching. Our results are indicative of a central role for HspA in amelioration of the harmful effect of light during heat stress and identified the possible sites of action of the small Hsp in vivo to be the PS II complex and the light-harvesting phycobilisomes.