Binding and functions of the two chloride ions in the oxygen-evolving center of photosystem II

Imaizumi, Ko; Ifuku, Kentaro

doi:10.1007/s11120-022-00921-y

Cited by 6 publications

(8 citation statements)

References 246 publications

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“…Therefore, it can be predicted that Cl-2 is the Cl − whose binding was especially stabilized by the mutation. While only the importance of Cl-1 has been revealed to date (36), the above observations suggest that not only Cl-1 but also Cl-2 can be important for the oxygen-evolving activity of PSII.…”

Section: Discussionmentioning

confidence: 91%

“…Cl − ions are known to be required for the oxygen-evolving activity of PSII, but the functions of the Cl − ions had long been a subject of debate (29)(30)(31)(32)(33)(34)(35). However, recent studies, most of which use cyanobacterial PSII, have advanced our understandings, especially of the functions of Cl-1 (36). D1-Glu333 and CP43-Glu354, involved in binding of Cl-1 and Cl-2, respectively, are both directly coordinated to the Mn 4 CaO 5 cluster (2).…”

mentioning

confidence: 99%

“…Green plants, including land plants and green algae, have a set of three extrinsic subunits, PsbO, PsbP, and PsbQ, which bind to the lumenal side of PSII (53), while cyanobacterial PSII binds PsbU and PsbV instead of PsbP and PsbQ (54,55). PsbU and PsbV are also present in red algal and diatom PSII, and structural comparison of the PSII complexes from cyanobacteria, red algae, diatoms, and green plants show that PsbP in green plant PSII spatially replaces PsbU and PsbV in the other types of PSII (5,36,49). Recent studies have also shown that water channels involving extrinsic subunits in cyanobacterial PSII (O4-PsbU channel and O1-PsbU/PsbV channel) are structurally conserved as PsbP-related water channels in green plant PSII (O4-PsbP channel and O1-PsbP channel) (6).…”

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confidence: 99%

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D139N mutation of PsbP enhances the oxygen-evolving activity of photosystem II through stabilized binding of a chloride ion

et al. 2022

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Photosystem II (PSII) is a multi-subunit membrane protein complex that catalyzes light-driven oxidation of water to molecular oxygen. The chloride ion (Cl−) has long been known as an essential cofactor for oxygen evolution by PSII, and two Cl− ions (Cl-1 and Cl-2) have been found to specifically bind near the Mn4CaO5 cluster within the oxygen-evolving center (OEC). However, despite intensive studies on these Cl− ions, little is known about the function of Cl-2, the Cl− ion that is associated with the backbone nitrogens of D1-Asn338, D1-Phe339, and CP43-Glu354. In green plant PSII, the membrane extrinsic subunits—PsbP and PsbQ—are responsible for Cl− retention within the OEC. The Loop 4 region of PsbP, consisting of highly conserved residues Thr135–Gly142, is inserted close to Cl-2, but its importance has not been examined to date. Here, we investigated the importance of PsbP-Loop 4 using spinach PSII membranes reconstituted with spinach PsbP proteins harboring mutations in this region. Mutations in PsbP-Loop 4 had remarkable effects on the rate of oxygen evolution by PSII. Moreover, we found that a specific mutation, PsbP-D139N, significantly enhanced the oxygen-evolving activity in the absence of PsbQ, but not significantly in its presence. The D139N mutation increased the Cl− retention ability of PsbP and induced a unique structural change in the OEC, as indicated by light-induced Fourier transform infrared (FTIR) difference spectroscopy and theoretical calculations. Our findings provide insight into the functional significance of Cl-2 in the water-oxidizing reaction of PSII.

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Section: Discussionmentioning

confidence: 91%

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confidence: 99%

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confidence: 99%

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D139N mutation of PsbP enhances the oxygen-evolving activity of photosystem II through stabilized binding of a chloride ion

et al. 2022

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“…D1-Asn298, which H-bonds to D1-His190 to promote Tyr Z oxidation, was in a similar position to that found in oxygen-evolving complexes but binding of Ycf48 likely disrupts the microenvironment around the D1-Tyr161/D1-His190/D1-Asn298 triad preventing efficient oxidation of Tyr Z 30 . Importantly, there was no indication in the structure for the presence of bound Mn or Ca ions or the two chloride ions, Cl-1 and Cl-2, required for functionality of the oxygen-evolving complex 31 .…”

Section: Resultsmentioning

confidence: 98%

The Ycf48 accessory factor occupies the site of the oxygen-evolving manganese cluster during photosystem II biogenesis

Zhao

Vercellino

Knoppová

et al. 2022

Preprint

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Robust oxygenic photosynthesis requires a suite of accessory factors to ensure efficient assembly and repair of the oxygen-evolving photosystem two (PSII) complex. The highly conserved Ycf48 assembly factor binds to the newly synthesized D1 reaction center polypeptide and promotes the initial steps of PSII assembly, but its binding site is unclear. Here we have used cryo-electron microscopy to determine the structure of a cyanobacterial PSII D1/D2 reaction center assembly complex with Ycf48 attached. Ycf48, a 7-bladed beta propeller, binds to the amino-acid residues of D1 that ultimately ligate the Mn4CaO5 cluster that catalyzes water oxidation, thereby preventing the premature binding of Mn2+ and Ca2+ ions and protecting the site from damage. Interactions with D2 help explain how Ycf48 promotes assembly of the D1/D2 complex. Overall, our work provides new insights into the early stages of PSII assembly and the structural changes that create the binding site for the Mn4CaO5 cluster.

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“…Vinyard et al (2019) showed that Cl plays an important role in the photoassembly of the OEC by tuning the affinity of various amino acid residues for manganese (Mn). Imaizumi & Ifuku (2022) proposed individual roles for the two chlorides attached to the Mn cluster of OEC. It has been shown that release of Cl À from its binding sites within the OEC enhances H 2 O 2 formation (Arat o et al, 2004;Posp ı sil, 2016;Posp ı sil et al, 2022).…”

Section: Chlorinementioning

confidence: 99%

Linking the key physiological functions of essential micronutrients to their deficiency symptoms in plants

Lilay,

Thiébaut,

du Mee

et al. 2024

New Phytologist

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SummaryIn this review, we untangle the physiological key functions of the essential micronutrients and link them to the deficiency responses in plants. Knowledge of these responses at the mechanistic level, and the resulting deficiency symptoms, have improved over the last decade and it appears timely to review recent insights for each of them. A proper understanding of the links between function and symptom is indispensable for an accurate and timely identification of nutritional disorders, thereby informing the design and development of sustainable fertilization strategies. Similarly, improved knowledge of the molecular and physiological functions of micronutrients will be important for breeding programmes aiming to develop new crop genotypes with improved nutrient‐use efficiency and resilience in the face of changing soil and climate conditions.

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Binding and functions of the two chloride ions in the oxygen-evolving center of photosystem II

Cited by 6 publications

References 246 publications

D139N mutation of PsbP enhances the oxygen-evolving activity of photosystem II through stabilized binding of a chloride ion

D139N mutation of PsbP enhances the oxygen-evolving activity of photosystem II through stabilized binding of a chloride ion

The Ycf48 accessory factor occupies the site of the oxygen-evolving manganese cluster during photosystem II biogenesis

Linking the key physiological functions of essential micronutrients to their deficiency symptoms in plants

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