1F1C

CRYSTAL STRUCTURE OF CYTOCHROME C549

Summary for 1F1C

• Entry DOI: 10.2210/pdb1f1c/pdb
• Descriptor: CYTOCHROME C549, HEME C (3 entities in total)
• Functional Keywords: dimeric cytochrome, electron transport
• Biological source: Arthrospira maxima
• Cellular location: Cellular thylakoid membrane; Peripheral membrane protein; Lumenal side: P82603
• Total number of polymer chains: 2
• Total formula weight: 29661.10

Authors

Kerfeld, C.A.,Sawaya, M.R.,Yeates, T.O.,Krogmann, D.W. (deposition date: 2000-05-18, release date: 2001-08-08, Last modification date: 2024-10-16)

Primary citation

Sawaya, M.R.,Krogmann, D.W.,Serag, A.,Ho, K.K.,Yeates, T.O.,Kerfeld, C.A.
Structures of cytochrome c-549 and cytochrome c6 from the cyanobacterium Arthrospira maxima.
Biochemistry, 40:9215-9225, 2001

PubMed Abstract: Cytochrome c(6) and cytochrome c-549 are small (89 and 130 amino acids, respectively) monoheme cytochromes that function in photosynthesis. They appear to have descended relatively recently from the same ancestral gene but have diverged to carry out very different functional roles, underscored by the large difference between their midpoint potentials of nearly 600 mV. We have determined the X-ray crystal structures of both proteins isolated from the cyanobacterium Arthrospira maxima. The two structures are remarkably similar, superimposing on backbone atoms with an rmsd of 0.7 A. Comparison of the two structures suggests that differences in solvent exposure of the heme and the electrostatic environment of the heme propionates, as well as in heme iron ligation, are the main determinants of midpoint potential in the two proteins. In addition, the crystal packing of both A. maxima cytochrome c-549 and cytochrome c(6) suggests that the proteins oligomerize. Finally, the cytochrome c-549 dimer we observe can be readily fit into the recently described model of cyanobacterial photosystem II.

PubMed: 11478889
DOI: 10.1021/bi002679p

Experimental method

X-RAY DIFFRACTION (2.3 Å)