Interaction of heme with a synthetic peptide mimicking the putative heme-binding site of histidine-rich glycoprotein.
We synthesized a hexapeptide, Gly-His-His-Pro-His-Gly, previously identified as a tandem motif in the histidine-rich glycoprotein (HRG) which has multiple heme-binding sites. Binding of heme to the peptide was demonstrated by the characteristic difference spectrum showing a close resemblance to that of HRG, implying that the peptide binds heme through biaxial coordination with histidine imidazoles. Furthermore, the EPR spectra of the heme-peptide and heme-HRG complexes were almost completely identical in pattern, showing signals characteristic of the low spin iron. The results suggest that the synthetic peptide simulates the heme-binding properties of HRG and that each tandem motif in HRG serves as a unitary binding site for heme.
Katagiri
M
M
Department of Chemistry, Osaka Kyoiku University, Japan.
Tsutsui
K
K
Yamano
T
T
Shimonishi
Y
Y
Ishibashi
F
F
D001665:Binding Sites; D001667:Binding, Competitive; D004578:Electron Spin Resonance Spectroscopy; D006418:Heme / Q000378:metabolism*; D006427:Hemin / Q000378:metabolism; D010446:Peptide Fragments / Q000138:chemical synthesis / Q000378:metabolism*; D011485:Protein Binding; D011506:Proteins / Q000378:metabolism*; D000099053:Histidine-Rich Glycoprotein
D010446:Peptide Fragments; D011506:Proteins; D000099053:Histidine-Rich Glycoprotein; D006418:Heme; D006427:Hemin