5CXM

Crystal structure of the cyanobacterial plasma membrane Rieske protein PetC3 from Synechocystis PCC 6803

Summary for 5CXM

• Entry DOI: 10.2210/pdb5cxm/pdb
• Descriptor: Cytochrome b6/f complex iron-sulfur subunit, FE2/S2 (INORGANIC) CLUSTER, NICKEL (II) ION, ... (5 entities in total)
• Functional Keywords: petc3, sll1182, rieske protein, 2fe-2s cluster, oxidoreductase, electron transport, plasma membrane, lipoprotein, cyanobacteria, synechocystis pcc 6803, metal binding protein
• Biological source: Synechocystis sp.
• Total number of polymer chains: 4
• Total formula weight: 45916.88

Authors

Veit, S.,Takeda, K.,Miki, K.,Roegner, M. (deposition date: 2015-07-29, release date: 2016-08-03, Last modification date: 2024-10-30)

Primary citation

Veit, S.,Takeda, K.,Tsunoyama, Y.,Baymann, F.,Nevo, R.,Reich, Z.,Rogner, M.,Miki, K.,Rexroth, S.
Structural and functional characterisation of the cyanobacterial PetC3 Rieske protein family.
Biochim. Biophys. Acta, 1857:1879-1891, 2016

PubMed Abstract: The cyanobacterium Synechocystis PCC 6803 possesses three Rieske isoforms: PetC1, PetC2 and PetC3. While PetC1 and PetC2 have been identified as alternative subunits of the cytochrome bf complex (bf), PetC3 was localized exclusively within the plasma membrane. The spatial separation of PetC3 from the photosynthetic and respiratory protein complexes raises doubt in its involvement in bioenergetic electron transfer. Here we report a detailed structural and functional characterization of the cyanobacterial PetC3 protein family indicating that PetC3 is not a component of the bf and the photosynthetic electron transport as implied by gene annotation. Instead PetC3 has a distinct function in cell envelope homeostasis. Especially proteomic analysis shows that deletion of petC3 in Synechocystis PCC 6803 primarily affects cell envelope proteins including many nutrient transport systems. Therefore, the observed downregulation in the photosynthetic electron transport - mainly caused by photosystem 2 inactivation - might constitute a stress adaptation. Comprehensive in silico sequence analyses revealed that PetC3 proteins are periplasmic lipoproteins tethered to the plasma membrane with a subclass consisting of soluble periplasmic proteins, i.e. their N-terminal domain is inconsistent with their integration into the bf. For the first time, the structure of PetC3 was determined by X-ray crystallography at an atomic resolution revealing significant high similarities to non-bf Rieske subunits in contrast to PetC1. These results suggest that PetC3 affects processes in the periplasmic compartment that only indirectly influence photosynthetic electron transport. For this reason, we suggest to rename "Photosynthetic electron transport Chain 3" (PetC3) proteins as "periplasmic Rieske proteins" (Prp).

PubMed: 27663073
DOI: 10.1016/j.bbabio.2016.09.007

Experimental method

X-RAY DIFFRACTION (1.7 Å)