8HN3

Soluble domain of cytochrome c-556 from Chlorobaculum tepidum

Summary for 8HN3

• Entry DOI: 10.2210/pdb8hn3/pdb
• Descriptor: Cytochrome c-556, HEME C, SULFATE ION, ... (6 entities in total)
• Functional Keywords: cytochrome c, electron transport, photosynthesis, green sulfur bacteria, cytochrome bc complex
• Biological source: Chlorobaculum tepidum
• Total number of polymer chains: 2
• Total formula weight: 18093.13

Authors

Kishimoto, H.,Azai, C.,Yamamoto, T.,Mutoh, R.,Nakaniwa, T.,Tanaka, H.,Kurisu, G.,Oh-oka, H. (deposition date: 2022-12-07, release date: 2023-07-05, Last modification date: 2024-11-06)

Primary citation

Kishimoto, H.,Azai, C.,Yamamoto, T.,Mutoh, R.,Nakaniwa, T.,Tanaka, H.,Miyanoiri, Y.,Kurisu, G.,Oh-Oka, H.
Soluble domains of cytochrome c-556 and Rieske iron-sulfur protein from Chlorobaculum tepidum: Crystal structures and interaction analysis.
Curr Res Struct Biol, 5:100101-100101, 2023

PubMed Abstract: In photosynthetic green sulfur bacteria, the electron transfer reaction from menaquinol:cytochrome oxidoreductase to the P840 reaction center (RC) complex occurs directly without any involvement of soluble electron carrier protein(s). X-ray crystallography has determined the three-dimensional structures of the soluble domains of the gene product and Rieske iron-sulfur protein (ISP). The former is a mono-heme cytochrome with an α-absorption peak at 556 nm. The overall fold of the soluble domain of cytochrome -556 (designated as cyt -556) consists of four α-helices and is very similar to that of water-soluble cyt -554 that independently functions as an electron donor to the P840 RC complex. However, the latter's remarkably long and flexible loop between the α3 and α4 helices seems to make it impossible to be a substitute for the former. The structure of the soluble domain of the Rieske ISP (Rieske protein) shows a typical β-sheets-dominated fold with a small cluster-binding and a large subdomain. The architecture of the Rieske protein is bilobal and belongs to those of -type Rieske ISPs. Nuclear magnetic resonance (NMR) measurements revealed weak non-polar but specific interaction sites on Rieske protein when mixed with cyt -556. Therefore, menaquinol:cytochrome oxidoreductase in green sulfur bacteria features a Rieske/cyt complex tightly associated with membrane-anchored cyt -556.

PubMed: 37180033
DOI: 10.1016/j.crstbi.2023.100101

Experimental method

X-RAY DIFFRACTION (1.65 Å)