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Here, we have compiled a nuclear magnetic resonance (NMR)-derived set of nuclear Overhauser enhancement (NOE) distance and dihedral angle restraints that allow for the calculation of the structure of the NDH-1 complex subunit CupS from Thermosynechococcus elongatus in solution. These restraints to calculate the structure in solution of CupS have been deposited to the Protein Data Bank (www.rcsb.org) under PDB-ID accession number 2MXA. This is the first experimental data set published to compute the three-dimensional structure of CupS. This structure is presented in the research article "Solution structure of the NDH-1 complex subunit CupS from Thermosynechococcus elongatus" published by Korste et al. in Biochim. Biophys. Acta 1847(2015)1212-1219 [1]. The cyanobacterial multi-subunit membrane protein complex NDH-1 structurally and functionally relates to Complex I of eubacteria and mitochondria. The NDH-1 complex is mechanistically involved in respiration and cyclic electron transfer around photosystem I (PSI) as well as in a unique mechanism for inorganic carbon concentration.

The cyanobacterial NADPH:plastoquinone oxidoreductase complex (NDH-1), that is related to Complex I of eubacteria and mitochondria, plays a pivotal role in respiration as well as in cyclic electron transfer (CET) around PSI and is involved in a unique carbon concentration mechanism (CCM). Despite many achievements in the past, the complex protein composition and the specific function of many subunits of the different NDH-1 species remain elusive. We have recently discovered in a NDH-1 preparation from Thermosynechococcus elongatus two novel single transmembrane peptides (NdhP, NdhQ) with molecular weights below 5 kDa. Here we show that NdhP is a unique component of the ∼ 450 kDa NDH-1L complex, that is involved in respiration and CET at high CO2 concentration, and not detectable in the NDH-1MS and NDH-1MS' complexes that play a role in carbon concentration. C-terminal fusion of NdhP with his-tagged superfolder GFP and the subsequent analysis of the purified complex by electron microscopy and single particle averaging revealed its localization in the NDH-1L specific distal unit of the NDH-1 complex, that is formed by the subunits NdhD1 and NdhF1. Moreover, NdhP is essential for NDH-1L formation, as this type of NDH-1 was not detectable in a ΔndhP::Km mutant.