Structural highlights
Function[CYC6_THEEB] Functions as an electron carrier between membrane-bound cytochrome b6-f and photosystem I in oxygenic photosynthesis. Publication Abstract from PubMedNative cytochrome c6 was purified from an extract of strain BP-1 of the thermophilic cyanobacterium Thermosynechococcus elongatus. The protein was crystallized, and with only slight modifications of the buffer and vapour-diffusion conditions two different space groups were observed, namely H3 and C2. Both crystal structures were solved; they contained three and six molecules per asymmetric unit and were refined to 1.7 and 2.25 A resolution, respectively. To date, the structure of native cytochrome c6 from T. elongatus has only been reported as a monomer using NMR spectroscopy, i.e. without addressing putative oligomerization, and related structures have only previously been solved using X-ray crystallography after recombinant gene overexpression in Escherichia coli. The reported space groups of related cyanobacterial cytochrome c6 structures differ from those reported here. Interestingly, the protein-protein interfaces that were observed utilizing X-ray crystallography could also explain homo-oligomerization in solution; specifically, trimerization is indicated by infra-red dynamic light scattering and blue native gel electrophoresis in solution. Trimers were also detected by mass spectrometry. Furthermore, there is an indication of post-translational methylation in the crystal structure. Additionally, the possibility of modifying the crystal size and the redox activity in the context of photosynthesis is shaping the investigated cytochrome as a highly suitable model protein for advanced serial crystallography at highly brilliant X-ray free-electron laser sources. Crystal structures of native cytochrome c6 from Thermosynechococcus elongatus in two different space groups and implications for its oligomerization.,Falke S, Feiler C, Chapman H, Sarrou I Acta Crystallogr F Struct Biol Commun. 2020 Sep 1;76(Pt 9):444-452. doi:, 10.1107/S2053230X20010249. Epub 2020 Aug 20. PMID:32880593[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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