5B5N
Crystal structure of the Ba-substituted LH1-RC complex from Tch. tepidum
This is a non-PDB format compatible entry.
Summary for 5B5N
| Entry DOI | 10.2210/pdb5b5n/pdb |
| Related | 5B5M |
| Descriptor | Photosynthetic reaction center cytochrome c subunit, BACTERIOPHEOPHYTIN A, Ubiquinone-8, ... (18 entities in total) |
| Functional Keywords | bacterial photosynthesis, light-harvesting complex, photosynthesis |
| Biological source | Thermochromatium tepidum More |
| Total number of polymer chains | 72 |
| Total formula weight | 782466.01 |
| Authors | Wang-Otomo, Z.-Y.,Yu, L.-J. (deposition date: 2016-05-12, release date: 2017-03-22, Last modification date: 2023-11-08) |
| Primary citation | Yu, L.J.,Kawakami, T.,Kimura, Y.,Wang-Otomo, Z.Y. Structural Basis for the Unusual Qy Red-Shift and Enhanced Thermostability of the LH1 Complex from Thermochromatium tepidum. Biochemistry, 55:6495-6504, 2016 Cited by PubMed Abstract: While the majority of the core light-harvesting complexes (LH1) in purple photosynthetic bacteria exhibit a Q absorption band in the range of 870-890 nm, LH1 from the thermophilic bacterium Thermochromatium tepidum displays the Q band at 915 nm with an enhanced thermostability. These properties are regulated by Ca ions. Substitution of the Ca with other divalent metal ions results in a complex with the Q band blue-shifted to 880-890 nm and a reduced thermostability. Following the recent publication of the structure of the Ca-bound LH1-reaction center (RC) complex [Niwa, S., et al. (2014) Nature 508, 228], we have determined the crystal structures of the Sr- and Ba-substituted LH1-RC complexes with the LH1 Q band at 888 nm. Sixteen Sr and Ba ions are identified in the LH1 complexes. Both Sr and Ba are located at the same positions, and these are clearly different from, though close to, the Ca-binding sites. Conformational rearrangement induced by the substitution is limited to the metal-binding sites. Unlike the Ca-LH1-RC complex, only the α-polypeptides are involved in the Sr and Ba coordinations in LH1. The difference in the thermostability between these complexes can be attributed to the different patterns of the network formed by metal binding. The Sr- and Ba-LH1-RC complexes form a single-ring network by the LH1 α-polypeptides only, in contrast to the double-ring network composed of both α- and β-polypeptides in the Ca-LH1-RC complex. On the basis of the structural information, a combined effect of hydrogen bonding, structural integrity, and charge distribution is considered to influence the spectral properties of the core antenna complex. PubMed: 27933779DOI: 10.1021/acs.biochem.6b00742 PDB entries with the same primary citation |
| Experimental method | X-RAY DIFFRACTION (3.3 Å) |
Structure validation
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