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Publication Abstract from PubMed

Bacteria with the simplest system for solar energy absorption and conversion use various types of light-harvesting complexes for these purposes. Light-harvesting complex 2 (LH2), an important component of the bacterial photosynthetic apparatus, has been structurally well characterized among purple non-sulfur bacteria. In contrast, so far only one high-resolution LH2 structure from sulfur bacteria is known. Here, we report the near-atomic resolution cryoelectron microscopy (cryo-EM) structure of the LH2 complex from the purple sulfur bacterium Ectothiorhodospira haloalkaliphila, which allowed us to determine the predominant polypeptide composition of this complex and the identification of the most probable type of its carotenoid. Comparison of our structure with the only known LH2 complex from a sulfur bacterium revealed severe differences in the overall ring-like organization. Expanding the architectural universe of bacterial light-harvesting complexes, our results demonstrate that, as observed for non-sulfur bacteria, the LH2 complexes of sulfur bacteria may also exhibit various types of spatial organization.

Near-atomic cryo-EM structure of the light-harvesting complex LH2 from the sulfur purple bacterium Ectothiorhodospira haloalkaliphila.,Burtseva AD, Baymukhametov TN, Bolshakov MA, Makhneva Zcapital KA, Cyrillic, Mardanov AV, Tsedilin AM, Zhang H, Popov VO, Ashikhmin AA, Boyko KM Structure. 2024 Dec 16:S0969-2126(24)00528-8. doi: 10.1016/j.str.2024.11.015. PMID:39694041^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.