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Cytochromec−Crown Ether Complexes as Supramolecular Catalysts: Cold-Active Synzymes for Asymmetric Sulfoxide Oxidation in Methanol

Suzumura, Atsuko and Paul, Dharam and Sugimoto, Hideki and Shinoda, Satoshi and Julian, Ryan R. and Beauchamp, J. L. and Teraoka, Junji and Tsukube, Hiroshi (2005) Cytochromec−Crown Ether Complexes as Supramolecular Catalysts: Cold-Active Synzymes for Asymmetric Sulfoxide Oxidation in Methanol. Inorganic Chemistry, 44 (4). pp. 904-910. ISSN 0020-1669. https://resolver.caltech.edu/CaltechAUTHORS:20170411-103059669

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Abstract

A series of supramolecular complexes of various cytochrome c proteins with 18-crown-6 derivatives behave as cold-active synzymes in the H_2O_2 oxidation of racemic sulfoxides. This interesting behavior contrasts with native functionality, where the employed proteins act as electron transfer carriers. ESI-MS, UV, CD, and Raman spectroscopic characterizations reveal that four or five 18-crown-6 molecules strongly bind to the surface of the cytochrome c and also that nonnatural low-spin hexacoordinate heme structures are induced in methanol. Significantly, crown ether complexation can convert catalytically inactive biological forms to catalytically active artificial forms. Horse heart, pigeon breast, and yeast cytochromes c all stereoselectively oxidize (S)-isomers of methyl tolyl sulfoxide and related sulfoxides upon crown ether complexation. These supramolecular catalysts show the highest efficiency and enantiomer selectivity at −40 °C in the H_2O_2-dependent sulfoxide oxidation, while oxidative decomposition of the heme moieties predominantly occurs at room temperature. The oxidation reactivity of the employed sulfoxides is apparently related to steric constraints and electrochemical oxidation potentials of their S O bonds. Among the cytochrome c complexes, yeast cytochrome c demonstrates the lowest catalytic activity and degradation reactivity. It has a significantly different protein sequence, suggesting that crown ether complexation effectively activates heme coordination but may additionally alter the native backbone structure. The proper combination of cytochrome c proteins, 18-crown-6 receptors, and external circumstances can be used to successfully generate “protein-based supramolecular catalysts” exhibiting nonbiological reactivities.


Item Type:Article
Related URLs:
URLURL TypeDescription
http://dx.doi.org/10.1021/ic0486567DOIArticle
http://pubs.acs.org/doi/suppl/10.1021/ic0486567PublisherSupporting Information
ORCID:
AuthorORCID
Julian, Ryan R.0000-0003-1580-8355
Beauchamp, J. L.0000-0001-8839-4822
Additional Information:© 2005 American Chemical Society. Received September 24, 2004. Publication Date (Web): January 28, 2005. The authors are grateful to Professor Rafael Vazquez-Duhalt of UNAM of Mexico for valuable comments on cytochrome c catalysts. They also thank JASCO Industry and the Sumica Analytical Center for providing useful information on the stereochemistry determination of sulfoxides. This research was supported in part by Grants-in-Aid (13874077 and 1301250) from the Japan Society for the Promotion of Science.
Funders:
Funding AgencyGrant Number
Japan Society for the Promotion of Science (JSPS)13874077
Japan Society for the Promotion of Science (JSPS)1301250
Issue or Number:4
Record Number:CaltechAUTHORS:20170411-103059669
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:20170411-103059669
Official Citation:Cytochrome c−Crown Ether Complexes as Supramolecular Catalysts:  Cold-Active Synzymes for Asymmetric Sulfoxide Oxidation in Methanol Atsuko Suzumura, Dharam Paul, Hideki Sugimoto, Satoshi Shinoda, Ryan R. Julian, J. L. Beauchamp, Junji Teraoka, and Hiroshi Tsukube Inorganic Chemistry 2005 44 (4), 904-910 DOI: 10.1021/ic0486567
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:76508
Collection:CaltechAUTHORS
Deposited By: Tony Diaz
Deposited On:11 Apr 2017 17:49
Last Modified:27 Apr 2020 23:04

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