De novo designed cyclic-peptide heme complexes.
The structural characterization of de novo designed metalloproteins together with determination of chemical reactivity can provide a detailed understanding of the relationship between protein structure and functional properties. Toward this goal, we have prepared a series of cyclic peptides that bind to water-soluble metalloporphyrins (FeIII and CoIII). Neutral and positively charged histidine-containing peptides bind with a high affinity, whereas anionic peptides bind only weakly to the negatively charged metalloporphyrin. Additionally, it was found that the peptide becomes helical only in the presence of the metalloporphyrin. CD experiments confirm that the metalloporphyrin binds specific cyclic peptides with high affinity and with isodichroic behavior. Thermal unfolding experiments show that the complex has "native-like" properties. Finally, NMR spectroscopy produced well dispersed spectra and experimental restraints that provide a high-resolution solution structure of the complexed peptide.
Rosenblatt
Michael M
MM
Department of Chemistry, University of Illinois at Urbana-Champaign, 600 South Mathews Avenue, Urbana, IL 61801, USA.
Wang
Jiangyun
J
Suslick
Kenneth S
KS
D000595:Amino Acid Sequence; D002942:Circular Dichroism; D006418:Heme / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D008665:Metalloporphyrins / Q000737:chemistry; D008958:Models, Molecular; D008969:Molecular Sequence Data; D010455:Peptides / Q000737:chemistry*; D011166:Porphyrins / Q000737:chemistry; D011485:Protein Binding; D011487:Protein Conformation; D017510:Protein Folding; D017433:Protein Structure, Secondary; D013053:Spectrophotometry; D013696:Temperature; D013816:Thermodynamics; D014466:Ultraviolet Rays
D008665:Metalloporphyrins; D010455:Peptides; D011166:Porphyrins; D006418:Heme