화학공학소재연구정보센터
Biochemical and Biophysical Research Communications, Vol.443, No.4, 1131-1135, 2014
Cytochrome c(6B) of Synechococcus sp WH 8102-Crystal structure and basic properties of novel c(6)-like family representative
cytochromes c are soluble electron carriers of relatively low molecular weight, containing single heme moiety. In cyanobacteria cytochrome c(6) participates in electron transfer from cytochrome b(6)f complex to photosystem I. Recent phylogenetic analysis revealed the existence of a few families of proteins homologous to the previously mentioned. Cytochrome c(6A) from Arabidopsis thaliana was identified as a protein responsible for disulfide bond formation in response to intracellular redox state changes and C-550 is well known element of photosystem II. However, function of cytochromes marked as c(6B), c(6c) and cm as well as the physiological process in which they take a part still remain unidentified. Here we present the first structural and biophysical analysis of cytochrome from the C-6B family from mesophilic cyanobacteria Synechococcus sp. WH 8102. Purified protein was crystallized and its structure was refined at 1.4 angstrom resolution. Overall architecture of this polypeptide resembles typical I-class cytochromes c. The main features, that distinguish described protein from cytochrome c(6), are slightly red-shifted alpha band of UV Vis spectrum as well as relatively low midpoint potential (113.2 +/- 2.2 mV). Although, physiological function of cytochrome c(6B) has yet to be determined its properties probably exclude the participation of this protein in electron trafficking between b(6)f complex and photosystem I. (C) 2013 Elsevier Inc. All rights reserved.