Microbiology Graduate Group, University of California, Davis, CA 95616, USA.
Life Sciences Department, The Natural History Museum, London SW7 5BD, UK.
Genes (Basel). 2021 Mar 16;12(3):426. doi: 10.3390/genes12030426.
Sulfide inhibits oxygenic photosynthesis by blocking electron transfer between HO and the oxygen-evolving complex in the D1 protein of Photosystem II. The ability of cyanobacteria to counter this effect has implications for understanding the productivity of benthic microbial mats in sulfidic environments throughout Earth history. In Lake Fryxell, Antarctica, the benthic, filamentous cyanobacterium creates a 1-2 mm thick layer of 50 µmol L O in otherwise sulfidic water, demonstrating that it sustains oxygenic photosynthesis in the presence of sulfide. A metagenome-assembled genome of indicates a genetic capacity for oxygenic photosynthesis, including multiple copies of (encoding the D1 protein of Photosystem II), and anoxygenic photosynthesis with a copy of (encoding the sulfide quinone reductase protein that oxidizes sulfide). The genomic content of is consistent with sulfide tolerance mechanisms including increasing expression or directly oxidizing sulfide with sulfide quinone reductase. However, the ability of the organism to reduce Photosystem I via sulfide quinone reductase while Photosystem II is sulfide-inhibited, thereby performing anoxygenic photosynthesis in the presence of sulfide, has yet to be demonstrated.
硫化物通过阻断 HO 与光系统 II D1 蛋白中的氧释放复合体之间的电子转移来抑制放氧光合作用。蓝细菌抵抗这种效应的能力对于理解地球历史上含硫环境中底栖微生物席的生产力具有重要意义。在南极洲的弗莱克斯湖，底栖丝状蓝细菌 在其他硫化物水中产生了 1-2 毫米厚的 50 µmol L O 层，表明它在存在硫化物的情况下维持着放氧光合作用。 的宏基因组组装基因组表明其具有进行放氧光合作用的遗传能力，包括多个 （编码光系统 II 的 D1 蛋白）和进行厌氧光合作用的 拷贝（编码将硫化物氧化的硫醌还原酶蛋白）。 的基因组内容与硫化物耐受机制一致，包括增加 表达或直接用硫醌还原酶氧化硫化物。然而，该生物体在光系统 II 被硫化物抑制的情况下通过硫醌还原酶还原光系统 I 的能力，从而在存在硫化物的情况下进行厌氧光合作用，尚未得到证实。
