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Isocyanides as ligand-directed indicators of Cu(I) coordination in copper proteins - probing the inequivalence of the Cu(I) centers in reduced dopamine-beta-monooxygenase
Citation
Reedy, BJ and Murthy, NN and Karlin, KD and Blackburn, NJ, Isocyanides as ligand-directed indicators of Cu(I) coordination in copper proteins - probing the inequivalence of the Cu(I) centers in reduced dopamine-beta-monooxygenase, Journal of the American Chemical Society, 117, (39) pp. 9826-9831. ISSN 0002-7863 (1995) [Refereed Article]
Abstract
The use of isocyanides as ligand-directed probes of Cu(I) coordination in proteins has been investigated. Reaction of 2,6-dimethylphenyl isocyanide (DIMPI) with reduced dopamine-β-monooxygenase (DβM) indicates the initial formation of monoisocyanide complexes at each of the two coppers (Cu A and Cu B ) with different frequencies (2148 and 2129 cm -1 ) indicative of inequivalent Cu(I) coordination at each copper. However, further addition of DIMPI leads to formation of a species containing multiple isocyanide ligands, believed to be a trisisocyanide adduct with a single IR band at 2160 cm -1 . This titration behavior can be interpreted by the active site model Cu A I (His) 2 Xâ€"CuB I (His) 2 Y (X = His; Y = Met) where the first stage of the reaction with isocyanide is the formation of a mono-DIMPI four-coordinate complex at each Cu, giving rise to the two observed IR bands (2148 and 2129 cm -1 ) provided the protein ligands X and Y are different. The second stage is the displacement of protein-bound ligands by the isocyanide to form a protein-bound bis or tris complex (2160 cm -1 ). Closely analogous chemistry involving the reaction of DIMPI with deoxyHc is described, which illustrates the generality of isocyanides as probes of Cu(I) coordination in copper proteins. A model system [Cu I (MePY2)(DIMPI)]ClO4, II, is also described in which identical isocyanide-binding chemistry can be demonstrated, thus validating the conclusions on the protein systems. The crystal structure of II is described, and the clean conversion of II to a trisisocyanide complex is demonstrated by FTIR and FT Raman spectroscopy. © 1995, American Chemical Society. All rights reserved.
Item Details
| Item Type: | Refereed Article |
|---|---|
| Research Division: | Chemical Sciences |
| Research Group: | Inorganic Chemistry |
| Research Field: | Bioinorganic Chemistry |
| Objective Division: | Expanding Knowledge |
| Objective Group: | Expanding Knowledge |
| Objective Field: | Expanding Knowledge in the Chemical Sciences |
| Author: | Reedy, BJ (Dr Brian Reedy) |
| ID Code: | 5753 |
| Year Published: | 1995 |
| Web of Science® Times Cited: | 23 |
| Deposited By: | Applied Science |
| Deposited On: | 1995-08-01 |
| Last Modified: | 2011-08-25 |
| Downloads: | 0 |
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