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Preparation and Spectroscopic Studies of Cobalt(II)-Stellacyanin

McMillin, David R. and Holwerda, Robert A. and Gray, Harry B. (1974) Preparation and Spectroscopic Studies of Cobalt(II)-Stellacyanin. Proceedings of the National Academy of Sciences of the United States of America, 71 (4). pp. 1339-1341. ISSN 0027-8424. http://resolver.caltech.edu/CaltechAUTHORS:MCMpnas74a

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Abstract

The cobalt(II) derivative of the "blue" copper protein stellacyanin has been prepared, and its visible-ultraviolet spectrum is reported. Tryptophan fluorescence quenching and p-mercuribenzoate titration results strongly suggest that Co(II) and Cu(II) compete for the same stellacyanin binding site and that a cysteine sulfur atom is coordinated in both cases. This interpretation is supported by the finding of an intense band at 355 nm in Co(II)-stellacyanin attributable to a charge transfer transition of the RS- Co(II) type. The visible absorption spectrum of Co(II)-stellacyanin exhibits band maxima at 540, 625, and 655 nm. These bands are attributable to d-d transitions originating in a high-spin Co(II) center. It is suggested that a correspondence exists between charge transfer bands observed at 355 and 300 nm in the Co(II) derivative to those found at 604 and 450 nm in the native protein. It is concluded that the intense 604-nm peak in Cu(II)-stellacyanin is attributable to a cys-S Cu(II) charge transfer transition.


Item Type:Article
Additional Information:Copyright © 1974 by The National Academy of Sciences. Contributed by Harry B. Gray, January 10, 1974. We thank the National Science Foundation for support of this research. This is Contribution no. 4813 from the Arthur Amos Noyes Laboratory.
Subject Keywords:blue copper protein, metal replacement, electronic spectroscopy, cysteine ligand
Record Number:CaltechAUTHORS:MCMpnas74a
Persistent URL:http://resolver.caltech.edu/CaltechAUTHORS:MCMpnas74a
Alternative URL:http://www.pnas.org/cgi/content/abstract/71/4/1339
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:609
Collection:CaltechAUTHORS
Deposited By: Archive Administrator
Deposited On:01 Sep 2005
Last Modified:14 Nov 2014 19:18

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