8Z81

Photosynthetic LH2-LH1 complex from the purple bacterium Halorhodospira halophila

Summary for 8Z81

• Entry DOI: 10.2210/pdb8z81/pdb
• EMDB information: 39835
• Descriptor: Antenna complex, alpha/beta subunit, (1R)-2-{[{[(2S)-2,3-DIHYDROXYPROPYL]OXY}(HYDROXY)PHOSPHORYL]OXY}-1-[(PALMITOYLOXY)METHYL]ETHYL (11E)-OCTADEC-11-ENOATE, BACTERIOCHLOROPHYLL A, ... (10 entities in total)
• Functional Keywords: lh2-lh1 complex, photosynthesis
• Biological source: Halorhodospira halophila; More
• Total number of polymer chains: 54
• Total formula weight: 533679.89

Authors

Tani, K.,Nagashima, K.V.P.,Kanno, R.,Hiwatashi, N.,Kawakami, M.,Nakata, K.,Nagashima, S.,Inoue, K.,Takaichi, S.,Purba, E.R.,Hall, M.,Yu, L.-J.,Madigan, M.T.,Mizoguchi, A.,Humbel, B.M.,Kimura, Y.,Wang-Otomo, Z.-Y. (deposition date: 2024-04-21, release date: 2025-02-19)

Primary citation

Tani, K.,Nagashima, K.V.P.,Kojima, R.,Kondo, M.,Kanno, R.,Satoh, I.,Kawakami, M.,Hiwatashi, N.,Nakata, K.,Nagashima, S.,Inoue, K.,Isawa, Y.,Morishita, R.,Takaichi, S.,Purba, E.R.,Hall, M.,Yu, L.J.,Madigan, M.T.,Mizoguchi, A.,Humbel, B.M.,Kimura, Y.,Nagasawa, Y.,Dewa, T.,Wang-Otomo, Z.Y.
A distinct double-ring LH1-LH2 photocomplex from an extremophilic phototroph.
Nat Commun, 16:1410-1410, 2025

PubMed Abstract: Halorhodospira (Hlr.) halophila strain BN9622 is an extremely halophilic and alkaliphilic phototrophic purple sulfur bacterium isolated from a hypersaline lake in the Libyan Desert whose total salinity exceeded 35% at pH 10.7. Here we present a cryo-EM structure of the native LH1-LH2 co-complex from strain BN9622 at 2.22 Å resolution. Surprisingly, the LH1-LH2 co-complex consists of a double-ring cylindrical structure with the larger LH1 ring encircling a smaller LH2 ring. The Hlr. halophila LH1 contains 18 αβ-subunits and additional bacteriochlorophyll a (BChl a) molecules that absorb maximally at 797 nm. The LH2 ring is composed of 9 αβ-subunits, and the BChl a molecules in the co-complex form extensive intra- and inter-complex networks to allow near 100% efficiency of energy transfer to its surrounding LH1. The additional LH1-B797 BChls a are located in such a manner that they facilitate exciton transfer from monomeric BChls in LH2 to the dimeric BChls in LH1. The structural features of the strain BN9622 LH1-LH2 co-complex may have evolved to allow a minimal LH2 complex to maximize excitation transfer to the core complex and effectively harvest light in the physiologically demanding ecological niche of this purple bacterium.

PubMed: 39915441
DOI: 10.1038/s41467-024-55811-9

Experimental method

ELECTRON MICROSCOPY (2.2 Å)