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| LIGAND VARIATION AND METAL-ION BINDING-SPECIFICITY IN ZINC FINGER PEPTIDES |
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| Author(s): KRIZEK BA, MERKLE DL, BERG JM |
| Source: INORGANIC CHEMISTRY Volume: 32 Issue: 6 Pages: 937-940 Published: MAR 17 1993 |
| Times Cited: 129 References: 20 |
| Abstract: Three metal binding peptides with coordination sites CYS2HiS2, CYS3His, and CYS4 have been prepared and their metal binding properties characterized. The peptides are based on a zinc finger consensus sequence and have the sequences ProTyrLysCys4ProGluCys7GlyLysSerPheSerGlnysSerAspLeuValLysXaa20GhiArgTbrYaa24ThrGly (Xaa = Yaa = His; Xaa = His, Yaa = Cys; Xaa = Yaa = Cys). The dissociation constants for the peptide complexes with Co2+, Zn2+, and Cd2+ have been determined via a series of direct and competitive metal ion titrations. The trend in relative affinities of the peptides for Co2+ over Zn2+ can be semiquantitatively accounted for by the decrease in ligand field stabilization energy as imidazole ligands are replaced by thiolates. The affinity for Cd2+ increases by over two orders of magnitude for each thiolate for imidazole substitution, in keeping with hard-soft acid-base effects. Furthermore, the results reveal that the N2S2 coordination site is unique among the sites studied in allowing significant preferential binding of Zn2+ over both first row transition metals and second row elements such as Cd2+. |
| Document Type: Article |
| Language: English |
Addresses:
1. JOHNS HOPKINS UNIV, SCH MED, DEPT BIOPHYS & BIOPHYS CHEM, BALTIMORE, MD 21205 USA
2. JOHNS HOPKINS UNIV, DEPT CHEM, BALTIMORE, MD 21218 USA |
| Publisher: AMER CHEMICAL SOC, 1155 16TH ST, NW, WASHINGTON, DC 20036 |
| Subject Category: Chemistry, Inorganic & Nuclear |
| IDS Number: KT696 |
| ISSN: 0020-1669 |
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