1FI9

SOLUTION STRUCTURE OF THE IMIDAZOLE COMPLEX OF CYTOCHROME C

Summary for 1FI9

• Entry DOI: 10.2210/pdb1fi9/pdb
• Related: 1FI7
• Descriptor: CYTOCHROME C, IMIDAZOLE, HEME C (3 entities in total)
• Functional Keywords: cytochrome c, solution structure, electron transport
• Biological source: Equus caballus (horse)
• Cellular location: Mitochondrion matrix: P00004
• Total number of polymer chains: 1
• Total formula weight: 12413.19

Authors

Banci, L.,Bertini, I.,Liu, G.,Lu, J.,Reddig, T.,Tang, W.,Wu, Y.,Zhu, D. (deposition date: 2000-08-03, release date: 2000-08-23, Last modification date: 2024-10-16)

Primary citation

Banci, L.,Bertini, I.,Liu, G.,Lu, J.,Reddig, T.,Tang, W.,Wu, Y.,Zhu, D.
Effects of extrinsic imidazole ligation on the molecular and electronic structure of cytochrome c
J.Biol.Inorg.Chem., 6:628-637, 2001

PubMed Abstract: Although imidazole ligand binding to cytochrome c is not directly related to its physiological function, it has the potential to provide valuable information on the molecular and electronic structure of the protein. The solution structure of the imidazole adduct of oxidized horse heart cytochrome c (Im-cyt c) has been determined through 2D NMR spectroscopy. The Im-cyt c, 8 mM in 1.2 M imidazole solution at pH 5.7 and 313 K, provided altogether 2,542 NOEs (1,901 meaningful NOEs) and 194 pseudocontact shifts. The 35 conformers of the family show the RMSD values to the average structure of 0.063+/-0.007 nm for the backbone and 0.107+/-0.007 nm for all heavy atoms, respectively. The characterization of Im-cyt c is discussed in detail both in terms of structure and electronic properties. The replacement of the axial ligand Met80 with the exogenous imidazole ligand induces significant conformation changes in both backbone and side chains of the residues located in the distal axial ligand regions. The imidazole ligand binds essentially parallel to the imidazole of the proximal histidine, the two planes forming an angle of 8+/-7 degrees. The electron delocalization on the heme moiety and the magnetic susceptibility tensor are consistent with these structural features.

PubMed: 11472026
DOI: 10.1007/s007750100240

Experimental method

SOLUTION NMR