Subunit Q is required to stabilize the large complex of NADPH dehydrogenase in Synechocystis sp. strain PCC 6803
Subunit Q is required to stabilize the large complex of NADPH dehydrogenase in Synechocystis sp. strain PCC 6803
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需要亚基 Q 来稳定集胞藻中 NADPH 脱氢酶的大复合体。
DOI：
10.1104/pp.15.00503
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发表时间：
2015
期刊：
影响因子：
--
通讯作者：
Ma W
中科院分区：
文献类型：
--
作者：
Zhao J;Rong W;Gao F;Ogawa T;Ma W
在蓝藻中已鉴定出NADPH脱氢酶(NDH-1)的两个主要复合体。大型复合体(NDH-1L)包含NdhD1、NDhF1和NDHP，这些在中等大小的复合体(NDH-1M)中不存在。它们在呼吸作用、依赖于NDH-1的光系统I周围的循环电子传递和CO2吸收中发挥重要作用。从蓝藻聚胞藻中分离到两个对强光敏感的突变体，它们的生长对强光敏感，光系统I周围的电子传递受阻。用含转座子的文库转化PCC6803菌株。这两个突变体都在一个开放阅读框中有一个标签，编码的产物与NDH-1L复合体的一个单一跨膜小亚单位NdhQ高度同源，通过蛋白质组学策略鉴定，NdhQ存在于长链嗜热菌中。NdhQ的缺失将NDH-1L的一半分解为NDH-1M，因此会损害呼吸，但不会影响二氧化碳的吸收。在室温下与N-十二烷基-β-d-麦芽糖苷长时间孵育的类囊体膜上，ƊndhQ中剩余的ndh-1L被完全分解为ndh-1m，比野生型要快得多。在ndhP缺失突变体(Ɗndhp)的背景下，ndhQ的缺失几乎完全将ndh-1L分解为ndh-1M，与在ƊndhD_1/Ɗndh_2突变体中观察到的结果相似。因此，我们得出结论，NdhQ和NDHP都是稳定NDH-1L复合体所必需的。
Two major complexes of NADPH dehydrogenase (NDH-1) have been identified in cyanobacteria. A large complex (NDH-1L) contains NdhD1, NdhF1, and NdhP, which are absent in a medium size complex (NDH-1M). They play important roles in respiration, NDH-1-dependent cyclic electron transport around photosystem I, and CO2uptake. Two mutants sensitive to high light for growth and impaired in cyclic electron transport around photosystem I were isolated from the cyanobacteriumSynechocystissp. strain PCC 6803 transformed with a transposon-bearing library. Both mutants had a tag in an open reading frame encoding a product highly homologous to NdhQ, a single-transmembrane small subunit of the NDH-1L complex, identified inThermosynechococcus elongatusby proteomics strategy. Deletion ofndhQdisassembled about one-half of the NDH-1L to NDH-1M and consequently impaired respiration, but not CO2uptake. During prolonged incubation of the thylakoid membrane withn-dodecyl-β-d-maltoside at room temperature, the rest of the NDH-1L in ƊndhQwas disassembled completely to NDH-1M and was much faster than in the wild type. In thendhP-deletion mutant (ƊndhP) background, absence of NdhQ almost completely disassembled the NDH-1L to NDH-1M, similar to the results observed in the ƊndhD1/ƊndhD2mutant. We therefore conclude that both NdhQ and NdhP are essential to stabilize the NDH-1L complex.