Transmembrane Electron and Proton Transfer in Diheme‐Containing Succinate : Quinone Oxidoreductases

Lancaster, C. Roy D.; Betz, Yamila M.; Heit, Sabine; LaFontaine, Michael

doi:10.1002/ijch.201600139

Cited by 6 publications

(3 citation statements)

References 86 publications

(207 reference statements)

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“…The diheme-containing family of complex II, namely type A and B subfamilies, found in a wide range of bacteria, is of particular interest, because its members support transmembrane electron transfer 12 . This process may or may not be coupled to transmembrane proton transfer, depending on the species and the direction of the reaction catalyzed in vivo 13 . The proton-coupled electron transfer events of specific diheme QFRs have already been studied based on the X-ray crystal structures from Wolinella succinogenes 9 , 14 , 15 and Desulfovibrio gigas 10 .…”

Section: Introductionmentioning

confidence: 99%

Cryo-EM structure of trimeric Mycobacterium smegmatis succinate dehydrogenase with a membrane-anchor SdhF

et al. 2020

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Diheme-containing succinate:menaquinone oxidoreductases (Sdh) are widespread in Grampositive bacteria but little is known about the catalytic mechanisms they employ for succinate oxidation by menaquinone. Here, we present the 2.8 Å cryo-electron microscopy structure of a Mycobacterium smegmatis Sdh, which forms a trimer. We identified the membrane-anchored SdhF as a subunit of the complex. The 3 kDa SdhF forms a single transmembrane helix and this helix plays a role in blocking the canonically proximal quinone-binding site. We also identified two distal quinone-binding sites with bound quinones. One distal binding site is formed by neighboring subunits of the complex. Our structure further reveals the electron/ proton transfer pathway for succinate oxidation by menaquinone. Moreover, this study provides further structural insights into the physiological significance of a trimeric respiratory complex II. The structure of the menaquinone binding site could provide a framework for the development of Sdh-selective anti-mycobacterial drugs.

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Section: Introductionmentioning

confidence: 99%

Cryo-EM structure of trimeric Mycobacterium smegmatis succinate dehydrogenase with a membrane-anchor SdhF

et al. 2020

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“…Potentiometric titration of redox active diheme-containing membrane proteins is a helpful tool in explaining the mechanism by which electron transport is accomplished in these proteins. ,, − Discussion is especially facilitated if there is structural information available, which is the case for the CYBASC B-paralog from A. thaliana . To determine highly accurate E M values for both A- and B-paralogs, we used a newly designed spectroelectrochemical reflection cell, which allowed us to monitor the redox-induced absorption changes in real time and thereby to ensure the complete redox equilibration of our system.…”

Section: Discussionmentioning

confidence: 99%

Proton-Coupled Electron Transport in Two Distinct CYBASC Paralogs of Arabidopsis thaliana: A Comparative Characterization of Highly Conserved Tyrosine and Lysine Residues

et al. 2020

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CYBASC proteins are ascorbate (AscH − ) reducible, diheme b-containing integral membrane cytochrome b 561 proteins (cytb 561 ), which are proposed to be involved in AscH − recycling and facilitation of iron absorption. Two distinct CYBASC paralogs from the plant Arabidopsis thaliana, Atcytb 561 -A (A-paralog) and Atcytb 561 -B (B-paralog), have been found to differ in their visiblespectral characteristics and their interaction with AscH − and ferric iron chelates. A previously determined crystal structure of the Bparalog provides the first insights into the structural organization of a CYBASC member and implies hydrogen bonding between the substrate AscH − and the conserved lysine residues at positions 77 (B-K77) and 81 (B-K81). The function of the highly conserved tyrosine at position 70 (B-Y70) is not obvious in the crystal structure, but its localization indicates the possible involvement in proton-coupled electron transfer. Here we show that B-Y70 plays a major role in the modulation of the oxidation−reduction midpoint potential of the high-potential heme, E M (b H ), as well as in AscH − oxidation. Our results support the involvement of the functionally conserved B-K77 in the stabilization of the dianion Asc 2− . These findings are supported by the crystal structure of the Bparalog, but a comparative biochemical and biophysical characterization of the A-and B-paralogs implied distinct and more complex functions of the corresponding residues A-Y69 and A-K76 in the A-paralog. Our results emphasize the need for a high-resolution crystal structure of the A-paralog to illuminate the differences in functional organization between the two paralogs.

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“…Scheiner's report on a computational study of proton and ion conduction on a chain of water molecules [10] provides atomistic detail on proton and ion transfer. Proton transfer is also discussed in publications by Lancaster and co-workers, [11] Brzezinski's lab, [12] and Ä delroth's group. [13] The first article reviews transmembrane electron and proton transfer in quinone oxidoreductases, whereas the other two are experimental studies of proton transfer in cytochrome bo 3 from E. coli and ba 3 cytochrome c oxidase mutants from Thermus thermophilus.…”

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confidence: 99%

Charge Transfer in Proteins: In Celebration of Hemi Gutman's 80 th Birthday

Friedman

Agmon

2017

Israel Journal of Chemistry

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Transmembrane Electron and Proton Transfer in Diheme‐Containing Succinate : Quinone Oxidoreductases

Cited by 6 publications

References 86 publications

Cryo-EM structure of trimeric Mycobacterium smegmatis succinate dehydrogenase with a membrane-anchor SdhF

Cryo-EM structure of trimeric Mycobacterium smegmatis succinate dehydrogenase with a membrane-anchor SdhF

Proton-Coupled Electron Transport in Two Distinct CYBASC Paralogs of Arabidopsis thaliana: A Comparative Characterization of Highly Conserved Tyrosine and Lysine Residues

Charge Transfer in Proteins: In Celebration of Hemi Gutman's 80 th Birthday

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