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Title: Cytochrome c{sub 6B} of Synechococcus sp. WH 8102 – Crystal structure and basic properties of novel c{sub 6}-like family representative

Highlights: • Crystal structure of cytochrome c{sub 6B} from Synechococcus sp. WH 8102 was solved. • Basic biophysical properties of cytochrome c{sub 6B} were determined. • Cytochrome c{sub 6B} exhibits similar architecture to cytochrome c{sub 6}. • Organization of heme binding pocket of cytochrome c{sub 6B} differs from that of c{sub 6}. • Midpoint potential of cytochrome c{sub 6B} is significantly lower than of cytochrome c{sub 6}. - Abstract: Cytochromes c are soluble electron carriers of relatively low molecular weight, containing single heme moiety. In cyanobacteria cytochrome c{sub 6} participates in electron transfer from cytochrome b{sub 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{sub 6A} from Arabidopsis thaliana was identified as a protein responsible for disulfide bond formation in response to intracellular redox state changes and c{sub 550} is well known element of photosystem II. However, function of cytochromes marked as c{sub 6B}, c{sub 6C} and c{sub M} 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{sub 6B} family from mesophilic cyanobacteria Synechococcus sp.more » WH 8102. Purified protein was crystallized and its structure was refined at 1.4 Å resolution. Overall architecture of this polypeptide resembles typical I-class cytochromes c. The main features, that distinguish described protein from cytochrome c{sub 6}, are slightly red-shifted α band of UV–Vis spectrum as well as relatively low midpoint potential (113.2 ± 2.2 mV). Although, physiological function of cytochrome c{sub 6B} has yet to be determined its properties probably exclude the participation of this protein in electron trafficking between b{sub 6}f complex and photosystem I.« less
Authors:
 [1] ;  [2] ;  [3] ;  [3] ;  [4] ;  [1] ;  [1]
  1. Department of Biophysics, Faculty of Biotechnology, University of Wroclaw, F. Joliot Curie 14a, 50-383 Wroclaw (Poland)
  2. Center for Biocrystallographic Research, Institute of Bioorganic Chemistry, Polish Academy of Sciences, Poznan (Poland)
  3. Department of Crystallography, Faculty of Chemistry, A. Mickiewicz University, Poznan (Poland)
  4. (Poland)
Publication Date:
OSTI Identifier:
22416239
Resource Type:
Journal Article
Resource Relation:
Journal Name: Biochemical and Biophysical Research Communications; Journal Volume: 443; Journal Issue: 4; Other Information: Copyright (c) 2013 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
60 APPLIED LIFE SCIENCES; ARABIDOPSIS; BIOPHYSICS; CHARGE CARRIERS; CRYSTAL STRUCTURE; CYANOBACTERIA; CYTOCHROMES; DISULFIDES; ELECTRON TRANSFER; HEME; MOLECULAR WEIGHT; PHOTOSYNTHESIS; POLYPEPTIDES; RED SHIFT