Biochimica et Biophysica Acta-Bioenergetics最新文献_第4页

Corrigendum to “New insights into the involvement of residue D1/V185 in Photosystem II function in Synechocystis 6803 and Thermosynechococcus vestitus” [Biochim. Biophys. Acta Bioenerg. 1866 (2025) 149550] “残基D1/V185参与聚囊菌6803和残留热聚球菌光系统II功能的新认识”[生物化学]的更正。Biophys。生物质化学工程学报，2004,24(2):444 - 444。

IF 3.4 2区生物学 Q2 BIOCHEMISTRY & MOLECULAR BIOLOGY

Biochimica et Biophysica Acta-Bioenergetics

Pub Date : 2025-08-01 Epub Date: 2025-05-26 DOI: 10.1016/j.bbabio.2025.149558

Alain Boussac , Julien Sellés , Tania Tibiletti , Miwa Sugiura , Robert L. Burnap

引用次数: 0

Expansion microscopy reveals thylakoid organisation alterations due to genetic mutations and far-red light acclimation 扩增显微镜显示由于基因突变和远红光驯化引起的类囊体组织改变。

IF 3.4 2区生物学 Q2 BIOCHEMISTRY & MOLECULAR BIOLOGY

Biochimica et Biophysica Acta-Bioenergetics

Pub Date : 2025-08-01 Epub Date: 2025-03-13 DOI: 10.1016/j.bbabio.2025.149552

Jarne Berentsen, Peter R. Bos, Emilie Wientjes

The thylakoid membrane is the site of the light-dependent reactions of photosynthesis. It is a continuous membrane, folded into grana stacks and the interconnecting stroma lamellae. The CURVATURE THYLAKOID1 (CURT1) protein family is involved in the folding of the membrane into the grana stacks. The thylakoid membrane remodels its architecture in response to light conditions, but its 3D organisation and dynamics remain incompletely understood. To resolve these details, an imaging technique is needed that provides high-resolution 3D images in a high-throughput manner. Recently, we have used expansion microscopy, a technique that meets these criteria, to visualise the thylakoid membrane isolated from spinach. Here, we show that this protocol can also be used to visualise enveloped spinach chloroplasts. Additionally, we present an improved protocol for resolving the thylakoid structure of Arabidopsis thaliana. Using this protocol, we show the changes in thylakoid architecture in response to long-term far-red light acclimation and due to knocking out CURT1A. We show that far-red light acclimation results in higher grana stacks that are packed closer together. In addition, the distance between stroma lamellae, which are wrapped around the grana, decreases. In the curt1a mutant, grana have an increased diameter and height, and the distance between grana is increased. Interestingly, in this mutant, the stroma lamellae occasionally approach the grana stacks from the top. These observations show the potential of expansion microscopy to study the thylakoid membrane architecture.

类囊体膜是光合作用中依赖光的反应的场所。它是一个连续的膜，折叠成颗粒堆和相互连接的基质薄片。曲率THYLAKOID1 （CURT1）蛋白家族参与了膜折叠成颗粒堆的过程。类囊体膜在光照条件下重塑其结构，但其三维组织和动力学仍然不完全清楚。为了解决这些细节，需要一种成像技术，以高通量的方式提供高分辨率的3D图像。最近，我们使用了扩展显微镜，一种符合这些标准的技术，来观察从菠菜中分离出来的类囊体膜。在这里，我们展示了这个方案也可以用来可视化包裹菠菜叶绿体。此外，我们提出了一种改进的方案来解决拟南芥的类囊体结构。使用该方案，我们显示了类囊体结构的变化，以响应长期远红光驯化和敲除CURT1A。我们表明，远红光驯化导致更高的颗粒堆积在一起更紧密。此外，包裹在颗粒周围的基质薄片之间的距离减小。在curt1a突变体中，晶粒的直径和高度增加，晶粒之间的距离增加。有趣的是，在这个突变体中，基质薄片偶尔会从顶部接近颗粒堆。这些观察结果显示了扩展显微镜研究类囊体膜结构的潜力。

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引用次数: 0

Antarctic photosynthesis: energy transfer and charge separation in the diatom Chaetoceros simplex 南极光合作用：单面毛藻的能量转移和电荷分离。

IF 3.4 2区生物学 Q2 BIOCHEMISTRY & MOLECULAR BIOLOGY

Biochimica et Biophysica Acta-Bioenergetics

Pub Date : 2025-08-01 Epub Date: 2025-05-27 DOI: 10.1016/j.bbabio.2025.149560

Shu En Lee , Willem van de Poll , Volha Chukhutsina

The polar oceanic environment poses extreme challenges to photosynthetic organisms, which have evolved atypical strategies to maintain efficient photosynthesis in cold temperatures. Here, the psychrophilic diatom Chaetoceros simplex (C. simplex) is studied in vivo in the dark-adapted state using steady-state and time-resolved fluorescence methods. Our results show that all fucoxanthin chlorophyll a/c protein (FCP) antenna transfer energy to photosystem I (PSI) or photosystem II (PSII), with no detached FCPs. PSI exhibits no fluorescence of ‘red’ forms of chlorophyll (chl) beyond 700 nm in both 279 K and 77 K conditions. Despite this, it apparently has a long decay time of ~85 ps indicating the presence of a large core-antenna supercomplex. PSII has an average lifetime of ~500 ps in open state (Q_A oxidized) and ~1220 ps in closed state (Q_A reduced). PSII of C. simplex has kinetics that are slightly slower than temperate diatoms, suggesting larger antenna. In addition, fucoxanthin (fx) molecules of FCP that absorb in the 500–550 nm range (fx-red) transfer more energy to PSII than fx that absorb in the blue range (fx-blue, 462 nm max absorption). A subpopulation of red-shifted, aggregated FCPs are detected at 77 K, that are active in energy transfer uphill at 279 K. Overall, our results indicate relatively larger antenna of PSI and PSII and an absence of red chls in PSI of cold-adapted species, compared to temperate species.

极地海洋环境对光合生物提出了极端的挑战，这些生物已经进化出非典型的策略来维持在低温下有效的光合作用。本文采用稳态和时间分辨荧光方法，研究了在体内适应黑暗状态下的嗜冷硅藻单角毛藻（C. simplex）。结果表明，岩藻黄素叶绿素a/c蛋白（FCP）天线向光系统I （PSI）或光系统II （PSII）传递能量，不存在分离的FCP。在279 K和77 K条件下，PSI在700 nm以上没有“红色”形式的叶绿素（chl）荧光。尽管如此，它显然有~85 ps的长衰减时间，这表明存在一个大的核心天线超复体。PSII在开放状态（QA氧化）和关闭状态（QA还原）下的平均寿命分别为~500 ps和~1220 ps。单纯硅藻的PSII动力学略慢于温带硅藻，表明其天线较大。此外，FCP的岩藻黄素（fx）分子在500-550 nm范围内吸收（fx-red），比在蓝色范围吸收的fx分子（fx-blue，最大吸收462 nm）向PSII传递更多的能量。在77 K处检测到红移聚集的fcp亚群，它们在279 K上坡时活跃于能量转移。总体而言，我们的研究结果表明，与温带物种相比，冷适应物种的PSI和PSII的天线相对较大，并且在PSI中没有红chls。

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引用次数: 0

The role of retinal chromophore photoisomerization in enhanced inward proton-pumping activity of xenorhodopsin from Nanosalina 视网膜发色团光异构在纳米盐碱中增强异视紫红质向内质子泵送活性中的作用

IF 3.4 2区生物学 Q2 BIOCHEMISTRY & MOLECULAR BIOLOGY

Biochimica et Biophysica Acta-Bioenergetics

Pub Date : 2025-08-01 Epub Date: 2025-05-04 DOI: 10.1016/j.bbabio.2025.149556

Yuma Ito , Tatsuro Nishikino , Hideki Kandori , Yuji Furutani

Xenorhodopsin (XeR) is the first identified light-driven inward proton pump, exhibiting proton translocation vectoriality opposite to that of bacteriorhodopsin (BR)—a well-characterized outward proton pump rhodopsin. The molecular mechanism governing this vectoriality remains a fundamental question. A distinguishing feature of XeRs is the substitution of the second counterion (Asp212 in BR) with a proline residue located near the protonated retinal Schiff base (PRSB). The absence of a negatively charged residue in XeRs may hinder proton transfer from the Schiff base to the primary counterion (Asp85 in BR), a key determinant of vectoriality. Several studies have reported that XeR from Nanosalina (NsXeR) exhibits higher inward proton-pumping activity than other XeRs, although the underlying molecular mechanism remains unclear. In this study, we analyzed the early photointermediate (K) of NsXeR using light-induced difference Fourier transform infrared spectroscopy, revealing two characteristic features. First, the distinct hydrogen out-of-plane (HOOP) vibrations—indicative of retinal distortion—were absent, suggesting a minimally distorted retinal chromophore post-photoisomerization in NsXeR. Second, the PRSB exhibited a weaker hydrogen bond in the dark state. Interestingly, substituting Pro209 at the second counterion position with alanine or glycine (P209A and P209G) restored HOOP band intensity and strengthened the PRSB hydrogen bond. Importantly, the P209A and P209G mutants demonstrated reduced inward proton-pumping activity and slower recovery in the final thermal isomerization process compared to the wild type. These findings suggest that photoisomerization without retinal distortion enhances inward proton transport in NsXeR.

异视紫红质（XeR）是第一个被发现的光驱动向内质子泵，其质子转运矢量性与细菌视紫红质（BR）相反，后者是一种特性良好的向外质子泵视紫红质。控制这种矢量的分子机制仍然是一个基本问题。xer的一个显著特征是用位于质子化视网膜希夫碱（PRSB）附近的脯氨酸残基取代BR中的第二个对离子（Asp212）。xer中缺乏带负电荷的残基可能会阻碍质子从希夫碱转移到主要对偶离子（BR中的Asp85），这是矢量性的关键决定因素。一些研究报道了来自纳米盐的XeR （NsXeR）比其他XeR表现出更高的向内质子泵活性，尽管潜在的分子机制尚不清楚。本研究利用光致差分傅里叶变换红外光谱分析了NsXeR的早期光中间体(K)，揭示了两个特征。首先，明显的氢面外（HOOP）振动（表明视网膜扭曲）不存在，表明NsXeR光异构后视网膜发色团有轻微扭曲。其次，PRSB在暗态表现出较弱的氢键。有趣的是，用丙氨酸或甘氨酸（P209A和P209G）取代Pro209在第二个对偶位置恢复了HOOP带强度并增强了PRSB氢键。重要的是，与野生型相比，P209A和P209G突变体表现出向内质子泵送活性降低，在最终热异构化过程中恢复较慢。这些发现表明，无视网膜畸变的光异构化增强了NsXeR中向内的质子传递。

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引用次数: 0

ADP-inhibited structure of non-catalytic site-depleted FoF1-ATPase from thermophilic Bacillus sp. PS-3 嗜热芽孢杆菌PS-3非催化位点缺失fof1 - atp酶的adp抑制结构。

IF 3.4 2区生物学 Q2 BIOCHEMISTRY & MOLECULAR BIOLOGY

Biochimica et Biophysica Acta-Bioenergetics

Pub Date : 2025-04-01 Epub Date: 2025-01-07 DOI: 10.1016/j.bbabio.2025.149536

Ren Kobayashi , Astuki Nakano , Kaoru Mitsuoka , Ken Yokoyama

The F₁ domain of F_oF₁-ATP synthases/ATPases (F_oF₁) possesses three catalytic sites on the three αβ interfaces, termed α_Eβ_E, α_Dβ_D, and α_Tβ_T, located mainly on the β subunits. The enzyme also has three non-catalytic ATP-binding sites on the three αβ interfaces, located mainly on the α subunits. When ATP does not bind to the non-catalytic site, F_oF₁ becomes significantly prone to ADP inhibition, ultimately resulting in the loss of ATPase activity. However, the underlying mechanism of ADP inhibition remains unclear. Here, we report the cryo-EM structure of the non-catalytic site-depleted (ΔNC) F_oF₁ from thermophilic Bacillus sp. PS-3, which completely lacks the ability to bind ATP (and ADP) upon transitioning to the ADP-inhibited form. The structure closely resembled the 81° rotated structure of the wild-type F_oF₁, except for minor movements in the C-terminal region of the α subunit. In this structure, unlike the wild-type enzyme, the catalytic site at α_Dβ_D, responsible for ATP hydrolysis, was occupied by ADP-Mg, with the absence of Pi. Furthermore, the catalytic site at α_Eβ_E, where ATP enters the F₁ domain during steady-state catalysis, is occupied by ADP, seemingly impeding further ATP binding to the enzyme. The structure suggests that the ADP-inhibited form of the F₁ domain is more likely due to differences in the nucleotide-binding states at the catalytic sites rather than structural differences.

FoF1- atp合成酶/ atp酶（FoF1）的F1结构域在三个αβ界面上具有三个催化位点，分别为αEβE、αDβD和αTβT，主要位于β亚基上。该酶在三个αβ界面上也有三个非催化性atp结合位点，主要位于α亚基上。当ATP不与非催化位点结合时，FoF1明显容易受到ADP抑制，最终导致ATP酶活性丧失。然而，ADP抑制的潜在机制尚不清楚。在这里，我们报道了来自嗜热芽孢杆菌sp. PS-3的非催化位点缺失（ΔNC） FoF1的低温电镜结构，它在转变为ADP抑制形式时完全缺乏结合ATP（和ADP）的能力。该结构与野生型FoF1的81°旋转结构非常相似，除了α亚基的c端区域有轻微的运动。在该结构中，与野生型酶不同，α d- β d上负责ATP水解的催化位点被ADP-Mg占据，而Pi缺失。此外，在α - e - β e的催化位点，ATP在稳态催化过程中进入F1结构域，被ADP占据，似乎阻碍了ATP进一步与酶结合。该结构表明，F1结构域的adp抑制形式更可能是由于催化位点上核苷酸结合状态的差异，而不是结构差异。

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引用次数: 0

Structural study of the chlorophyll between Lhca8 and PsaJ in an Antarctica green algal photosystem I-LHCI supercomplex revealed by its atomic structure 南极绿藻光系统I-LHCI超配合物中Lhca8和PsaJ之间叶绿素的结构研究

IF 3.4 2区生物学 Q2 BIOCHEMISTRY & MOLECULAR BIOLOGY

Biochimica et Biophysica Acta-Bioenergetics

Pub Date : 2025-04-01 Epub Date: 2025-02-11 DOI: 10.1016/j.bbabio.2025.149543

Pi-Cheng Tsai, Koji Kato, Jian-Ren Shen, Fusamichi Akita

Coccomyxa subellipsoidea is an oleaginous, non-motile unicellular green microalga isolated from Antarctica, and is an attractive candidate for CO₂ fixation and biomass production. C. subellipsoidea is the first polar green alga whose genome has been sequenced. Understanding the structure of photosystems from C. subellipsoidea can provide more information about the conversion of light energy into chemical energy under extreme environments. Photosystems I (PSI) is one of the two photosystems highly conserved from cyanobacteria to vascular plants, and associates with a large amount of outer light-harvesting complex (LHC) which absorb light energy and transfer them to the core complex. Here, we determined the structure of the PSI-10 LHCIs and PSI-8 LHCIs supercomplexes from C. subellipsoidea at 1.92 Å and 2.06 Å resolutions by cryo-electron microscopy, respectively. The supercomplex is similar to PSI-LHCI from other green algae, whereas a large amount of water molecules is observed in our structure because of the high-resolution map. Two novel chlorophylls (Chls), Chl a321 in Lhca4 and Chl a314 in Lhca8, are observed at the lumenal side in our structure, in which Lhca8-Chl a314 provides a potential excitation energy transfer (EET) pathway between the inner-belt of LHCI and the core at the lumenal side. A total of three major EET pathways from LHCIs to PSI core are proposed, and C. subellipsoidea might adapt to the extreme environment by transferring energy in these three different EET pathways instead of by two major pathways proposed in other organisms.

Coccomyxa subbellipsoidea是一种从南极洲分离出来的产油、不活动的单细胞绿色微藻，是一种有吸引力的二氧化碳固定和生物质生产的候选藻类。C. subbellipsoidea是第一个基因组测序的极地绿藻。了解C. subbellipsoidea光系统的结构可以提供更多关于极端环境下光能转化为化学能的信息。光系统I （PSI）是蓝藻到维管植物中高度保守的两个光系统之一，它与大量的外部光收集复合体（LHC）有关，该复合体吸收光能并将其转移到核心复合体。在这里，我们用低温电子显微镜分别测定了C. subellipsoidea中PSI-10 LHCIs和PSI-8 LHCIs超配合物在1.92 Å和2.06 Å分辨率下的结构。该超复合物与其他绿藻的PSI-LHCI相似，而由于高分辨率的图谱，在我们的结构中观察到大量的水分子。在我们的结构中，在管侧观察到Lhca4中的Chl a321和Lhca8中的Chl a314两种新的叶绿素，其中Lhca8-Chl a314在LHCI内带和管侧核心之间提供了一个潜在的激发能传递（EET）途径。从lhci到PSI核心，C. subbellipsoidea可能通过这三种不同的EET途径来适应极端环境，而不是其他生物提出的两种主要的EET途径。

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引用次数: 0

New insights into the involvement of residue D1/V185 in photosystem II function in Synechocystis 6803 and Thermosynechococcus vestitus 残基D1/V185参与6803聚囊球菌和残余热聚球菌光系统II功能的新认识

IF 3.4 2区生物学 Q2 BIOCHEMISTRY & MOLECULAR BIOLOGY

Biochimica et Biophysica Acta-Bioenergetics

Pub Date : 2025-04-01 Epub Date: 2025-02-25 DOI: 10.1016/j.bbabio.2025.149550

Alain Boussac , Julien Sellés , Miwa Sugiura , Robert L. Burnap

The effects of D1-V185T and D1-V185N mutations in Photosystem II (PSII) from Thermosynechococcus vestitus (formerly T. elongatus) and Synechocystis 6803, respectively, were studied using both EPR and optical kinetics. EPR spectroscopy reveals the presence of a mixture of a S₂ state in a high spin configuration (S₂^HS) and in a low spin configuration (S₂^LS) in both mutants. In contrast to the S₂^HS in the wild type, the S₂^HS state in the D1-V185T mutant does not progress to the S₃ state at 198 K. This inability is likely due to alterations in the protonation state and hydrogen-bonding network around the Mn₄CaO₅ cluster. Optical studies show that these mutations significantly affect proton release during the S₃-to-S₀ transition. While the initial fast proton release associated with Tyr_Z^● formation remains unaffected within the resolution of our measurements, the second, and slower, proton release is delayed, suggesting that the mutations disrupt the hydrogen-bonding interactions necessary for efficient deprotonation of substrate water (O6). This disruption in proton transfer also correlates with slower water exchange in the S₃ state, likely due to non-native hydrogen bonds introduced by the threonine or asparagine side chains at position 185. These findings point to a critical role of D1-V185 in regulating both proton transfer dynamics and water binding, underscoring a complex interplay between structural and functional changes in PSII.

采用EPR和光学动力学方法研究了残留热聚球菌（原T. elongatus）和聚胞球菌6803的D1-V185T和D1-V185N突变对光系统II （PSII）的影响。EPR光谱揭示了两个突变体在高自旋构型（S2HS）和低自旋构型（S2LS）中存在S2态的混合物。与野生型的S2HS相比，D1-V185T突变体的S2HS状态在198 K时不会进展到S3状态。这种缺陷可能是由于质子化状态和Mn4CaO5簇周围的氢键网络的改变。光学研究表明，这些突变显著影响了s3到s0跃迁过程中的质子释放。虽然与TyrZ●形成相关的初始快速质子释放在我们测量的分辨率范围内不受影响，但第二次较慢的质子释放被延迟，这表明突变破坏了底物水有效去质子化所必需的氢键相互作用（O6）。这种质子转移的中断也与S3状态下较慢的水交换有关，可能是由于185位苏氨酸或天冬酰胺侧链引入的非天然氢键。这些发现表明D1-V185在调节质子转移动力学和水结合中起关键作用，强调了PSII结构和功能变化之间复杂的相互作用。

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引用次数: 0

Pinpoint introduction of functional molecular probe into the NqrB subunit of Na+-translocating NADH-ubiquinone oxidoreductase from Vibrio cholerae 功能分子探针在霍乱弧菌Na+易位nadh -泛醌氧化还原酶NqrB亚基中的精确引入。

IF 3.4 2区生物学 Q2 BIOCHEMISTRY & MOLECULAR BIOLOGY

Biochimica et Biophysica Acta-Bioenergetics

Pub Date : 2025-04-01 Epub Date: 2025-03-04 DOI: 10.1016/j.bbabio.2025.149551

Saya Miyachi , Hinako Tanaka , Moe Ishikawa , Danielle Mcfee , Wataru Aoki , Masatoshi Murai , Blanca Barquera , Hideto Miyoshi , Takahiro Masuya

The Na⁺-translocating NADH-ubiquinone oxidoreductase (Na⁺-NQR) is a key enzyme in the respiratory chain of numerous pathogenic bacteria, including Vibrio cholerae. The flexible cytoplasmic N-terminal region of the NqrB subunit (Met¹–Lys⁵⁴), which may play an important role in the final UQ reduction at the adjacent NqrA, is the target of specific inhibitors. If we can develop a new method that enables pinpoint introduction of functional probe molecules (such as fluorescent probes) into the N-terminal region, this could lead to new experimental ways of monitoring dynamic structural changes of the region. We previously showed that an electrophilic chemical group, which can be released from korormicin A-templated synthetic ligand, can be predominantly introduced into nucleophilic Lys²² as a “foothold” via ligand-directed (LD) substitution, but the subsequent conjugation of a functional probe molecule to the foothold by Cu⁺-catalyzed click chemistry required destruction of the enzyme. Accordingly, we now report the nondestructive conjugation of the functional molecule into the N-terminal region via a two-step conjugation technique: first, pinpoint introduction of a foothold tag containing a ring-strained cyclopropene by LD substitution using a new korormicin A-templated ligand (BEK-1) and second, direct conjugation of a fluorescent probe molecule containing tetrazine with the introduced cyclopropene by inverse electron-demand Diels-Alder-type click chemistry. Protein sequence analyses revealed that the fluorescent probe is attached to Lys¹⁹, His²⁰, or Lys²² in the region. The extent of conjugation of the fluorescent probe was approximately halved in the presence of different inhibitors, suggesting that the inhibitor binding induces structural changes around the residues.

Na+易位nadh -泛醌氧化还原酶（Na+-NQR）是包括霍乱弧菌在内的许多致病菌呼吸链中的关键酶。NqrB亚基（Met1-Lys54）的柔性胞质n端区域可能在相邻NqrA的最终UQ还原中起重要作用，是特异性抑制剂的靶点。如果我们能够开发出一种新的方法，能够精确地将功能探针分子（如荧光探针）引入n端区域，这可能会导致新的实验方法来监测该区域的动态结构变化。我们之前的研究表明，可以从korormicin a模板化的合成配体中释放的亲电化学基团可以主要通过配体定向（LD）取代引入亲核的Lys22中作为“立足点”，但随后通过Cu+催化的点击化学将功能探针分子偶联到立足点需要破坏酶。因此，我们现在报道了通过两步共轭技术将功能分子无损地偶联到n端区域：首先，使用新的korormicin a模板配体（BEK-1）通过LD取代精确地引入含有环应变环丙烯的立足标记；其次，通过反向电按需diels - alder型点击化学将含有四嗪的荧光探针分子与引入的环丙烯直接偶联。蛋白质序列分析表明，荧光探针可以附着在Lys19、His20或Lys22上。在不同抑制剂的存在下，荧光探针的共轭程度大约减半，这表明抑制剂的结合诱导了残基周围的结构变化。

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引用次数: 0

Mitochondrial potassium channels: New properties and functions 线粒体钾通道：新的性质和功能

IF 3.4 2区生物学 Q2 BIOCHEMISTRY & MOLECULAR BIOLOGY

Biochimica et Biophysica Acta-Bioenergetics

Pub Date : 2025-04-01 Epub Date: 2025-02-09 DOI: 10.1016/j.bbabio.2025.149546

Adam Szewczyk , Piotr Bednarczyk , Bogusz Kulawiak , Monika Żochowska , Barbara Kalenik , Joanna Lewandowska , Karolina Pytlak , Shur Gałecka , Antoni Wrzosek , Piotr Koprowski

Mitochondria are recently implicated in phenomena such as cytoprotection, cellular senescence, tumor metabolism, and inflammation. The basis of these processes relies on biochemical functions of mitochondria such as the synthesis of reactive oxygen species or biophysical properties such as the integrity of the inner mitochondrial membrane. The transport of potassium cations plays an important role in all these events. The K⁺ influx is mediated by potassium channels present in the inner mitochondrial membrane. In this article, we present an overview of our new findings on the properties of mitochondrial large-conductance calcium-activated and mitochondrial ATP-regulated potassium channels. This concerns the role of mitochondrial potassium channels in cellular senescence, and interactions with other mitochondrial proteins or small molecules such as quercetin, hemin, and hydrogen sulfide. We also discuss the prospects of research on potassium channels present in mitochondria.

线粒体最近涉及细胞保护、细胞衰老、肿瘤代谢和炎症等现象。这些过程的基础依赖于线粒体的生化功能，如活性氧的合成或生物物理特性，如线粒体内膜的完整性。钾离子的转运在所有这些过程中起着重要作用。K+内流是由存在于线粒体内膜的钾离子通道介导的。在本文中，我们概述了线粒体大电导钙激活和线粒体atp调节钾通道特性的新发现。这涉及线粒体钾通道在细胞衰老中的作用，以及与其他线粒体蛋白或小分子（如槲皮素、血红素和硫化氢）的相互作用。我们还讨论了线粒体钾离子通道的研究前景。

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引用次数: 0

Defining the direct electron transfer connection between alternative complex III and cytochrome oxidase in Flavobacterium johnsoniae 确定琼氏黄杆菌中选择性络合物III与细胞色素氧化酶之间的直接电子转移联系。

IF 3.4 2区生物学 Q2 BIOCHEMISTRY & MOLECULAR BIOLOGY

Biochimica et Biophysica Acta-Bioenergetics

Pub Date : 2025-04-01 Epub Date: 2025-02-14 DOI: 10.1016/j.bbabio.2025.149548

Katarzyna Lorencik , Robert Ekiert , Rafał Pietras , Joanna Ner-Kluza , Małgorzata Hopciaś , Artur Osyczka

Alternative complex III (ACIII) is an enzyme of electron transport chains in some bacterial species. ACIII, like cytochrome bc enzymes, oxidizes quinol and transfers electrons from quinol to electron acceptors located outside the membrane. Various proteins can functionally link ACIII with other enzymes. The structure of ACIII from Flavobacterium johnsoniae suggests that in this bacterium the membrane-anchored mobile mono-heme cytochrome c domain (mdA) of the ActA subunit of ACIII provides means for its connection with cytochrome aa₃ oxidase. Here, using a recently-developed genetic system for ACIII, we revealed that ACIII mutant deprived of mdA does not exhibit electron transfer activity towards cytochrome aa₃ oxidase in the cells and in the isolated membranes. These results indicate that mdA is the only carrier of electrons between the pentaheme core of ActA and cytochrome aa₃ oxidase. In addition, we heterologously expressed and purified mdA and ActE (another mono-heme subunit of ACIII) from Escherichia coli to identify the redox midpoint potentials of the hemes in these two domains. The obtained values analyzed in the context of the whole titration profiles of native ACIII and ACIII deprived of mdA provide first insights into the arrangement of heme redox potentials in the seven-heme chain formed by the ActA/ActE assembly.

选择性络合物III （ACIII）是一些细菌种类中的一种电子传递链酶。ACIII，像细胞色素bc酶一样，氧化喹啉并将电子从喹啉转移到位于膜外的电子受体。各种蛋白质可以将ACIII与其他酶连接起来。来自强johnsoniae黄杆菌的ACIII的结构表明，在该细菌中，ACIII的ActA亚基的膜锚定的移动单血红素细胞色素c结构域（mdA）为其与细胞色素aa3氧化酶的连接提供了途径。在这里，利用最近开发的ACIII遗传系统，我们发现剥夺mdA的ACIII突变体在细胞和分离膜中不表现出对细胞色素aa3氧化酶的电子转移活性。这些结果表明，mdA是ActA的五胺核和细胞色素aa3氧化酶之间的唯一电子载体。此外，我们从大肠杆菌中异种表达和纯化了mdA和ActE （ACIII的另一个单血红素亚基），以确定这两个区域血红素的氧化还原中点电位。在天然ACIII和剥夺mdA的ACIII的整个滴定谱的背景下分析所得值，首次深入了解了ActA/ActE组装形成的七血红素链中血红素氧化还原电位的排列。

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引用次数: 0