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Structure of the NDH-1MS complex from Thermosynechococcus elongatus
Structural highlights
FunctionNU1C_THEVB NDH-1 shuttles electrons from an unknown electron donor, via FMN and iron-sulfur (Fe-S) centers, to quinones in the respiratory and/or the photosynthetic chain. The immediate electron acceptor for the enzyme in this species is believed to be plastoquinone. Couples the redox reaction to proton translocation, and thus conserves the redox energy in a proton gradient.[HAMAP-Rule:MF_01350] Publication Abstract from PubMedPhotosynthetic organisms capture light energy to drive their energy metabolism, and employ the chemical reducing power to convert carbon dioxide (CO2) into organic molecules. Photorespiration, however, significantly reduces the photosynthetic yields. To survive under low CO2 concentrations, cyanobacteria evolved unique carbon-concentration mechanisms that enhance the efficiency of photosynthetic CO2 fixation, for which the molecular principles have remained unknown. We show here how modular adaptations enabled the cyanobacterial photosynthetic complex I to concentrate CO2 using a redox-driven proton-pumping machinery. Our cryo-electron microscopy structure at 3.2 A resolution shows a catalytic carbonic anhydrase module that harbours a Zn(2+) active site, with connectivity to proton-pumping subunits that are activated by electron transfer from photosystem I. Our findings illustrate molecular principles in the photosynthetic complex I machinery that enabled cyanobacteria to survive in drastically changing CO2 conditions. Redox-coupled proton pumping drives carbon concentration in the photosynthetic complex I.,Schuller JM, Saura P, Thiemann J, Schuller SK, Gamiz-Hernandez AP, Kurisu G, Nowaczyk MM, Kaila VRI Nat Commun. 2020 Jan 24;11(1):494. doi: 10.1038/s41467-020-14347-4. PMID:31980611[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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