INACTIVATION BY GENE DISRUPTION OF 2-CYSTEINE-PEROXIREDOXIN IN SYNECHOCYSTIS SP. PCC 6803 LEADS TO INCREASED STRESS SENSITIVITY
INACTIVATION BY GENE DISRUPTION OF 2-CYSTEINE-PEROXIREDOXIN IN SYNECHOCYSTIS SP. PCC 6803 LEADS TO INCREASED STRESS SENSITIVITY
复制标题
集胞藻中 2-半胱氨酸-过氧化氧还蛋白因基因破坏而失活。
DOI：
10.1034/j.1399-3054.1998.1040426.x
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发表时间：
1998
影响因子：
6.4
通讯作者：
K. Dietz
中科院分区：
文献类型：
--
作者：
B. Klughammer;M. Baier;K. Dietz
2-半胱氨酸-过氧化物酶（2-CP）是一类广泛存在的还原有毒烷基氢过氧化物的酶。在高等植物中，显示了核编码的2-CP被后期输入到叶绿体中;叶绿体是植物中最活跃的氧化代谢的位点（Baier和Dietz 1997，Plant J. 12. 179-190）。蓝绿藻集胞藻（EMBL acc. #D 64000）的基因组编码一个2-CP，该2-CP在基因水平上与高等植物2-CP具有60%的同源性，在成熟蛋白水平上具有约70%的同源性。为了阐明2-CP在光合生物中的生理意义，通过卡那霉素基因盒的插入，在集胞藻PCC 6803中突变2-CP基因。在完全分离后，分析突变株系的生长和光合参数。与野生型相比，突变体显示出降低的生长速率。降低生长培养基中Fe或微量元素的浓度后，生长抑制得到缓解。饱和光脉冲诱导的叶绿素a荧光瞬变被用作光合作用状态的指示剂。与野生型集胞藻相比，突变体的有效量子产率在较低的光强度下降低。同时，突变体的电子传递速率在较低的光强度下饱和。这些数据提供了第一个证据，表明2-CP在光合作用中起着关键的保护作用。
2-Cysteine-peroxiredoxins (2-CP) constitute a ubiquitous group of enzymes which reduce toxic alkyl hydroperoxides. In higher plants it was shown that the nuclear encoded 2-CPs are posttranslationally imported into the chloroplasts; the site of most active oxidative metabolism in plants (Baier and Dietz 1997, Plant J. 12. 179-190). The genome of the bluegreen alga Synechocystis (EMBL acc. # D64000) encodes a 2-CP which shares 60% homology to higher plant 2-CPs on the gene level and about 70% on the level of the mature protein. In order to elucidate the physiological significance of 2-CPs for photosynthetic organisms, the 2-CP gene was mutated in Synechocystis sp. PCC 6803 by insertion of a kanamycin gene cartridge. Following complete segregation mutant lines were analyzed for growth and photosynthetic parameters. The mutants revealed decreased growth rates as compared to the wild type. Growth inhibition was relieved after lowering the concentration of Fe or trace elements in the growth medium. Chlorophyll a fluorescence transients as induced by saturating light pulses were used as indicator for the state of photosynthesis. The effective quantum yield decreased at lower light intensities in the mutants as compared to the wild type Synechocystis. Simultaneously, electron transport rates saturated at lower light intensities in the mutants. These data provide the first evidence that 2-CPs play a pivotal protective role in photosynthesis.