Synthesis of highly selective fluorescent peptide probes for metal ions: tuning selective metal monitoring with secondary structure.
Metal selective fluorescent peptide probes (dansyl-Cys-X-Gly-His-X-Gly-Glu-NH2, X = Pro or Gly) were developed by synthesizing peptides containing His, Cys, and Glu residues with Pro-Gly sequence to stabilize a turn structure and Gly-Gly sequence to adopt a random coil. The probe containing two Gly-Gly sequences exhibited marked selectivity only for Cu2+ over 13 metal ions including competitive transition and Group I and II metal ions under physiological buffer condition. In contrast, the probe containing double Pro-Gly sequences showed high selectivity for Zn2+. The peptide probe containing one Pro-Gly sequence exhibited selectivity for Zn2+ and Cu2+. CD spectra indicated that the secondary structure of the probes played an important role in the selective metal monitoring and a pre-organized secondary structure is not required for the selective detection of Cu2+ ion, but is required for the detection of Zn2+. We investigated and characterized the binding affinity, binding stoichiometry, reversibility, and pH sensitivity of the peptide probes.
Joshi
Bishnu Prasad
BP
Bio-organic Chemistry Laboratory, Department of Chemistry, Inha University, 253 Younghyun-Dong, Nam-Gu, Inchon-City 402-751, Republic of Korea.
Lee
Keun-Hyeung
KH
D000595:Amino Acid Sequence; D002021:Buffers; D002412:Cations; D002942:Circular Dichroism; D003300:Copper / Q000032:analysis / Q000737:chemistry / Q000378:metabolism; D005456:Fluorescent Dyes / Q000138:chemical synthesis* / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D008670:Metals / Q000032:analysis* / Q000737:chemistry* / Q000378:metabolism; D008969:Molecular Sequence Data; D010455:Peptides / Q000138:chemical synthesis* / Q000378:metabolism; D011485:Protein Binding; D017433:Protein Structure, Secondary; D012680:Sensitivity and Specificity; D013050:Spectrometry, Fluorescence; D015032:Zinc / Q000032:analysis / Q000737:chemistry / Q000378:metabolism
D002021:Buffers; D002412:Cations; D005456:Fluorescent Dyes; D008670:Metals; D010455:Peptides; D003300:Copper; D015032:Zinc