Replacement of the methionine axial ligand in cytochrome c(550) by a lysine: effects on the haem electronic structure

The prosthetic group of low-spin haem proteins is an iron porphyrin with two axial ligands, typically histidine, methionine or lysine. Determining the geometry of the axial ligands is an important step in structural characterisation, particularly in the paramagnetic oxidised forms. This work extends...

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Bibliographic Details
Published in:FEBS letters 2002-01, Vol.510 (3), p.185-188
Main Authors: Louro, Ricardo O, de Waal, Ellen C, Ubbink, Marcellus, Turner, David L
Format: Article
Language:English
Subjects:
Amino Acid Substitution
Cyanides - chemistry
Cytochrome c Group - chemistry
Heme - chemistry
Ligands
Lysine - chemistry
Methionine - chemistry
Mutation
Nuclear Magnetic Resonance, Biomolecular
Paracoccus - enzymology
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Summary:The prosthetic group of low-spin haem proteins is an iron porphyrin with two axial ligands, typically histidine, methionine or lysine. Determining the geometry of the axial ligands is an important step in structural characterisation, particularly in the paramagnetic oxidised forms. This work extends earlier studies of the hyperfine nuclear magnetic resonance (NMR) shifts of haem substituents in bis-His and His-Met cytochromes to His-Lys co-ordination in the M100K mutant of Paracoccus versutus cytochrome c(550). The electronic structure of the His-Lys haem is shown to be similar to that produced by His-cyanide co-ordination, such that NMR can be used to determine the geometry of the His ligand.
ISSN:0014-5793
DOI:10.1016/S0014-5793(01)03272-0