Stabilization of hydrolytically labile iron(II)–cysteine peptide thiolate complexes in aqueous triton X-100 micelle solution: Spectroscopic properties mimicking of reduced rubredoxin
✍ Scribed by Wei-Yin Sun; Norikazu Ueyama; Akira Nakamura
- Publisher
- Wiley (John Wiley & Sons)
- Year
- 1998
- Tongue
- English
- Weight
- 121 KB
- Volume
- 46
- Category
- Article
- ISSN
- 0006-3525
No coin nor oath required. For personal study only.
✦ Synopsis
The absorption, CD, and 1 H-and 19 F-nmr spectroscopic features of Fe(II) complexes with a series of cysteine-containing oligopeptides were investigated in aqueous (H 2 O or D 2 O) 10% Triton X-100 micelle solution. The complexes with distal aromatic rings, [Fe(Zcys-Pro-Leu-cys-Gly-X) 2 ] 20 (Z Å benzyloxycarbonyl; X Å NH-C 6 H 4 -p-F, NH-CH 2 -CH 2 -C 6 H 4p-F, and Phe-OMe), were found to be quite stable in such aqueous micelle solution. The coordination of cysteine-peptide ligands to the Fe(II) ion is revealed by isotropically shifted 1 H-nmr signals due to the Cys C b H 2 protons occurring at 120 Ç 250 ppm in a D 2 O Triton X-100 micelle solution (10%) at 60ЊC that are very similar to those reported for native reduced rubredoxin. The high stability of these cysteine peptide-Fe(II) complexes in aqueous micellar system was explained by the combined contributions from NH{S hydrogen bonds and the effect of the proximity of aromatic groups. The existence of such NH{S hydrogen bonds and interactions between aromatic ring and sulfur atom was confirmed by 19 F-nmr spectral and 19 F spin-lattice relaxation times (T 1 ) measurements.