一个变种人,Δsll1252ins,产生以功能表征Sll1252。Δslll1252ins在70µmol光子m-2s-1和葡萄糖敏感性下表现出缓慢生长的表型。在Δsll1252ins中,PSII活动率没有受到影响,而全链电子传递活性降低了45%。sll1252的失活导致基因的上调,早期报道在DBMIB处理的野生型中诱导,这表明Sll1252可能参与了从还原PQ池到Cytb6/f的电子转移。DCMU对PSII活性的抑制作用在野生型和Δsll1252ins中均相似。然而,DBMIB对50%的全链电子传递活性抑制的浓度对于Δsll1252ins为140nM,对于野生型为300nM,确认Sll1252的行动地点。此外,Δsll1252ins中降低的PQ池的升高水平支持Sll1252在PQ池和Cytb6/f之间起作用。有趣的是,我们注意到Δsll1252ins通过插入天然转座子恢复为野生型表型,ISY523,在中断地点。Δsll1252-Ntrn,与野生型和Δsll1252-Ctrn(仅表达N末端区域)相比,仅表达Sll1252的C末端区域表现出缓慢的生长表型和无序的类囊体结构。总的来说,我们的数据表明,Sll1252通过Sll1252的N端和C端区域的协调功能调节PQ池和线性光合电子传输链中Cytb6/f复合物之间的电子转移。
A mutant, Δsll1252ins, was generated to functionally characterize Sll1252. Δsll1252ins exhibited a slow-growth phenotype at 70 µmol photons m-2 s-1 and glucose sensitivity. In Δsll1252ins, the rate of PSII activity was not affected, whereas the whole chain electron transport activity was reduced by 45%. The inactivation of sll1252 led to the upregulation of genes, which were earlier reported to be induced in DBMIB-treated wild-type, suggesting that Sll1252 may be involved in electron transfer from the reduced-PQ pool to Cyt b6/f. The inhibitory effect of DCMU on PSII activity was similar in both wild-type and Δsll1252ins. However, the concentration of DBMIB for 50% inhibition of whole chain electron transport activity was 140 nM for Δsll1252ins and 300 nM for wild-type, confirming the site of action of Sll1252. Moreover, the elevated level of the reduced-PQ pool in Δsll1252ins supports that Sll1252 functions between the PQ pool and Cyt b6/f. Interestingly, we noticed that Δsll1252ins reverted to wild-type phenotype by insertion of natural transposon, ISY523, at the disruption site. Δsll1252-Ntrn, expressing only the C-terminal region of Sll1252, exhibited a slow-growth phenotype and disorganized thylakoid structure compared to wild-type and Δsll1252-Ctrn (expressing only the N-terminal region). Collectively, our data suggest that Sll1252 regulates electron transfer between the PQ pool and the Cyt b6/f complex in the linear photosynthetic electron transport chain via coordinated function of both the N- and C-terminal regions of Sll1252.