TY - JOUR
T1 - Crystal structure of cytochrome c' from Rhodocyclus gelatinosus and comparison with other cytochromes c'
AU - Archer, Margarida
AU - Banci, Lucia
AU - Dikaya, Elena
AU - Romão, Maria J.
N1 - The authors thank C. Frazão for reading the manuscript and JNICT for financial support through the fellowship PRAXIS/BD/2795/94 (M.A.). The authors wish to thank I. Bertini and A. Xavier for helpful discussions and the financial support from the European Union (EC contract CHRX-CT94-0540 and CEC Contract BIO4-CT96 0413).
PY - 1997/10/1
Y1 - 1997/10/1
N2 - Cytochromes c' are heme proteins found in photosynthetic and denitrifying bacteria, where they are presumably involved in electron transport. The cytochrome c' isolated from the bacterium Rhodocyclus gelatinosus (RGCP) forms a homodimer with each polypeptide containing 129 residues. It has been crystallised in ammonium sulfate at pH 6. Crystals belong to space group P3121 with cell parameters a = 70.2 Å and c = 126.8 Å, which corresponds to a dimer in the asymmetric unit (VM = 3.5 Å3/Da). The crystal structure of RGCP was solved by the molecular replacement method and refined using data to 2.5-Å resolution. The final crystallographic R factor was 17.9% for all reflections (above 2 σ) in the resolution range 27.4 to 2.5 Å. The refined model includes 1876 non-hydrogen protein atoms and 56 water molecules. As typical of c-type cytochromes, the heme group is covalently bound to Cys-X-Y-Cys-His through thio-ether bonds, and His123 occupies the fifth axial coordination position. On the vacant 'distal' site; Phe16 blocks the direct access to the sixth coordination site, which is in a predominantly hydrophobic environment. In spite of the low sequence homology among cytochromes c' the overall fold is similar. The monomer structure consists of 4 anti-parallel α-helices and has random coils in the loops between the helices, and at the N- and C-termini. The subunits cross each other to form an X shape.
AB - Cytochromes c' are heme proteins found in photosynthetic and denitrifying bacteria, where they are presumably involved in electron transport. The cytochrome c' isolated from the bacterium Rhodocyclus gelatinosus (RGCP) forms a homodimer with each polypeptide containing 129 residues. It has been crystallised in ammonium sulfate at pH 6. Crystals belong to space group P3121 with cell parameters a = 70.2 Å and c = 126.8 Å, which corresponds to a dimer in the asymmetric unit (VM = 3.5 Å3/Da). The crystal structure of RGCP was solved by the molecular replacement method and refined using data to 2.5-Å resolution. The final crystallographic R factor was 17.9% for all reflections (above 2 σ) in the resolution range 27.4 to 2.5 Å. The refined model includes 1876 non-hydrogen protein atoms and 56 water molecules. As typical of c-type cytochromes, the heme group is covalently bound to Cys-X-Y-Cys-His through thio-ether bonds, and His123 occupies the fifth axial coordination position. On the vacant 'distal' site; Phe16 blocks the direct access to the sixth coordination site, which is in a predominantly hydrophobic environment. In spite of the low sequence homology among cytochromes c' the overall fold is similar. The monomer structure consists of 4 anti-parallel α-helices and has random coils in the loops between the helices, and at the N- and C-termini. The subunits cross each other to form an X shape.
KW - Cytochrome c'
KW - Electron transfer protein
KW - Rhodocyclus gelatinosus
KW - X-ray crystal structure
UR - http://www.scopus.com/inward/record.url?scp=0030830925&partnerID=8YFLogxK
U2 - 10.1007/s007750050176
DO - 10.1007/s007750050176
M3 - Article
AN - SCOPUS:0030830925
VL - 2
SP - 611
EP - 622
JO - JBIC Journal of Biological Inorganic Chemistry
JF - JBIC Journal of Biological Inorganic Chemistry
SN - 0949-8257
IS - 5
ER -