5h2f
From Proteopedia
Crystal structure of the PsbM-deletion mutant of photosystem II
Structural highlights
Function[PSBF_THEEB] This b-type cytochrome is tightly associated with the reaction center of photosystem II and possibly is part of the water-oxidation complex (By similarity).[HAMAP-Rule:MF_00643] [PSBL_THEEB] Required for PSII activity (By similarity). [PSBC_THEEB] One of the components of the core complex of photosystem II (PSII). It binds chlorophyll and helps catalyze the primary light-induced photochemical processes of PSII. PSII is a light-driven water:plastoquinone oxidoreductase, using light energy to abstract electrons from H(2)O, generating O(2) and a proton gradient subsequently used for ATP formation.[HAMAP-Rule:MF_01496][1] [2] [3] [PSBJ_THEEB] This protein is a component of the reaction center of photosystem II (By similarity). [PSBB_THEEB] One of the components of the core complex of photosystem II (PSII). It binds chlorophyll and helps catalyze the primary light-induced photochemical processes of PSII. PSII is a light-driven water:plastoquinone oxidoreductase, using light energy to abstract electrons from H(2)O, generating O(2) and a proton gradient subsequently used for ATP formation.[HAMAP-Rule:MF_01495][4] [5] [6] [PSBX_THEEB] Involved in the binding and/or turnover of quinones at the Q(B) site of Photosystem II.[7] [PSBO_THEEB] MSP binds to a putative Mn-binding protein and keeps 2 of the 4 Mn-atoms associated with PSII (By similarity). [CY550_THEEB] Low-potential cytochrome c that plays a role in the oxygen-evolving complex of photosystem II. It is not essential for growth under normal conditions but is required under low CO(2) concentrations.[HAMAP-Rule:MF_01378] [PSBU_THEEB] Stabilizes the structure of photosystem II oxygen-evolving complex (OEC), the ion environment of oxygen evolution and protects the OEC against heat-induced inactivation (By similarity).[HAMAP-Rule:MF_00589] [PSBI_THEEB] This protein is a component of the reaction center of photosystem II.[HAMAP-Rule:MF_01316] [PSBA1_THEEB] This is one of the two reaction center proteins of photosystem II. [PSBZ_THEEB] Controls the interaction of photosystem II (PSII) cores with the light-harvesting antenna. May also aid in binding of PsbK, Ycf12 and the oxygen-evolving complex to PSII, at least in vitro.[8] [PSBK_THEEB] This protein is a component of the reaction center of photosystem II.[HAMAP-Rule:MF_00441] [PSBT_THEEB] Seems to play a role in the dimerization of PSII.[9] [YCF12_THEEB] A core subunit of photosystem II (PSII).[HAMAP-Rule:MF_01329] [PSBE_THEEB] This b-type cytochrome is tightly associated with the reaction center of photosystem II and possibly is part of the water-oxidation complex.[HAMAP-Rule:MF_00642] Publication Abstract from PubMedPhotosystem II (PSII) is a membrane protein complex that performs light-induced electron transfer and oxygen evolution from water. PSII consists of 19 or 20 subunits in its crystal form and binds various cofactors such as chlorophyll a, plastoquinone, carotenoid, and lipids. After initial light excitation, the charge separation produces an electron, which is transferred to a plastoquinone molecule (QA) and then to another plastoquinone (QB). PsbM is a low-molecular-weight subunit with one transmembrane helix, and is located in the monomer-monomer interface of the PSII dimer. The function of PsbM has been reported to be stabilization of the PSII dimer and maintenance of electron transfer efficiency of PSII based on previous X-ray crystal structure analysis at a resolution of 4.2 A. In order to elucidate the structure-function relationships of PsbM in detail, we improved the quality of PSII crystals from a PsbM-deleted mutant (DeltaPsbM-PSII) of Thermosynechococcus elongatus, and succeeded in improving the diffraction quality to a resolution of 2.2 A. X-ray crystal structure analysis of DeltaPsbM-PSII showed that electron densities for the PsbM subunit and neighboring carotenoid and detergent molecules were absent in the monomer-monomer interface. The overall structure of DeltaPsbM-PSII was similar to wild-type PSII, but the arrangement of the hydrophobic transmembrane subunits was significantly changed by the deletion of PsbM, resulting in a slight widening of the lipid hole involving QB. The lipid hole-widening further induced structural changes of the bicarbonate ion coordinated to the non-heme Fe(ii) atom and destabilized the polypeptide chains around the QB binding site located far from the position of PsbM. The fluorescence decay measurement indicated that the electron transfer rate from QA to QB was decreased in DeltaPsbM-PSII compared with wild-type PSII. The functional change in electron transfer efficiency was fully interpreted based on structural changes caused by the deletion of the PsbM subunit. Mutual relationships between structural and functional changes in a PsbM-deletion mutant of photosystem II.,Uto S, Kawakami K, Umena Y, Iwai M, Ikeuchi M, Shen JR, Kamiya N Faraday Discuss. 2017 Mar 8. doi: 10.1039/c6fd00213g. PMID:28272640[10] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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Categories: Photosystem II | Thermosynechococcus elongatus | Ikeuchi, M | Iwai, M | Kamiya, N | Kawakami, K | Shen, J R | Umena, Y | Uto, S | Mutant | Photosynthesis | Photosystem ii | Psbm
