Interplay between LHCSR proteins and state transitions governs the NPQ response in Chlamydomonas during light fluctuations

Abstract

Photosynthetic organisms use sunlight as the primary energy source to fix CO 2 .However, in nature, light energy is highly variable, reaching levels of saturation for periods ranging from milliseconds to hours. In the green microalga Chlamydomonas reinhardtii, safe dissipation of excess light energy by nonphotochemical quenching (NPQ) is mediated by light-harvesting complex stressrelated (LHCSR) proteins and redistribution of light-harvesting antennae between the photosystems (state transition). Although each component

The role of BST4 in the pyrenoid ofChlamydomonas reinhardtii

“…S9 ). NPQ is mediated by multiple mechanisms and harbors multiple components (Erickson et al, 2015), one of them, termed energy-dependent quenching, ( qE ) is quickly induced and relaxed and is mostly mediated by the activity of the proton-sensing Light Harvesting Complex Stress related 3 ( LCHSR3 ) protein (Bonente et al, 2011; Peers et al, 2009; Steen et al, 2022; Tian et al, 2019). The magnitude of qE has recently been shown to be an indicator of the lumenal pH, the lower the pH, the higher the qE (Burlacot et al, 2022; Tian et al, 2019).…”

Plastoquinone pool redox state and control of state transitions in Chlamydomonas reinhardtii in darkness and under illumination

“…In general, the changes under individual wavelengths were seemingly more dependent on changes in light intensity than on the redox state of the PQ-pool, suggesting an additional layer of feedback control of light state. Such control might be important under fluctuating light where LHCSRs and state transitions both have been shown to contribute to NPQ (Steen et al 2022 ). Light intensity-dependent feedback in the fluorescence emission data (Fig.…”

Structures, arrangements and functions of LHC antennas for oxygenic photosynthetic organisms

“…真核光合生物进化出的 PsbS 蛋白或强光胁迫相关蛋白(LHCSR/LHCX) 在响应囊腔侧酸化、触发并调节 qE 过程中 发挥重要作用. 它们都属于 LHC 超级家族, 据推测绿藻的 LHCSR 和硅藻的 LHCX 可能结合 相当量的色素 [60,61] , 而 PsbS 的晶体结构已经在 2015 年得到解析. 中国科学院生物物理研究 所团队发现 PsbS 以同质二聚体的活性状态存在 [23] , 每个 PsbS 单体由四段跨膜螺旋组成, 形 成紧密的结构, 每个单体内部没有色素结合位点, 展现出与典型的三个跨膜螺旋和大量色素…”