5n1t

Publication Abstract from PubMed

Flavocytochrome c sulfide dehydrogenase from Thioalkalivibrio paradoxus (TpFCC) is a heterodimeric protein consisting of flavin- and monohaem c-binding subunits. TpFCC was co-purified and co-crystallized with the dimeric copper-binding protein TpCopC. The structure of the TpFCC-(TpCopC)2 complex was determined by X-ray diffraction at 2.6 A resolution. The flavin-binding subunit of TpFCC is structurally similar to those determined previously, and the structure of the haem-binding subunit is similar to that of the N-terminal domain of dihaem FCCs. According to classification based on amino-acid sequence, TpCopC belongs to a high-affinity CopC subfamily characterized by the presence of a conserved His1-Xxx-His3 motif at the N-terminus. Apparently, a unique alpha-helix which is present in each monomer of TpCopC at the interface with TpFCC plays a key role in complex formation. The structure of the copper-binding site in TpCopC is similar to those in other known CopC structures. His3 is not involved in binding to the copper ion and is 6-7 A away from this ion. Therefore, the His1-Xxx-His3 motif cannot be considered to be a key factor in the high affinity of CopC for copper(II) ions. It is suggested that the TpFCC-(TpCopC)2 heterotetramer may be a component of a large periplasmic complex that is responsible for thiocyanate metabolism.

Structure of the flavocytochrome c sulfide dehydrogenase associated with the copper-binding protein CopC from the haloalkaliphilic sulfur-oxidizing bacterium Thioalkalivibrio paradoxusARh 1.,Osipov EM, Lilina AV, Tsallagov SI, Safonova TN, Sorokin DY, Tikhonova TV, Popov VO Acta Crystallogr D Struct Biol. 2018 Jul 1;74(Pt 7):632-642. doi:, 10.1107/S2059798318005648. Epub 2018 Jun 8. PMID:29968673^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.