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Evolution of the C30 Carotenoid Synthase CrtM for Function in a C40 Pathway

Umeno, Daisuke and Tobias, Alexander V. and Arnold, Frances H. (2002) Evolution of the C30 Carotenoid Synthase CrtM for Function in a C40 Pathway. Journal of Bacteriology, 184 (23). pp. 6690-6699. ISSN 0021-9193. PMCID PMC135437.

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The C30 carotene synthase CrtM from Staphylococcus aureus and the C40 carotene synthase CrtB from Erwinia uredovora were swapped into their respective foreign C40 and C30 biosynthetic pathways (heterologously expressed in Escherichia coli) and evaluated for function. Each displayed negligible ability to synthesize the natural carotenoid product of the other. After one round of mutagenesis and screening, we isolated 116 variants of CrtM able to synthesize C40 carotenoids. In contrast, we failed to find a single variant of CrtB with detectable C30 activity. Subsequent analysis revealed that the best CrtM mutants performed comparably to CrtB in an in vivo C40 pathway. These mutants showed significant variation in performance in their original C30 pathway, indicating the emergence of enzymes with broadened substrate specificity as well as those with shifted specificity. We discovered that Phe 26 alone determines the specificity of CrtM. The plasticity of CrtM with respect to its substrate and product range highlights the potential for creating further new carotenoid backbone structures.

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Arnold, Frances H.0000-0002-4027-364X
Additional Information:© 2002, American Society for Microbiology. Received 6 June 2002/ Accepted 28 August 2002 D.U. acknowledges support from the Japan Society for the Promotion of Science. A.V.T. acknowledges a Natural Sciences and Engineering Research Council of Canada PGS A scholarship. This research was supported in part by the U.S. National Science Foundation and Maxygen, Inc.
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Japan Society for the Promotion of Science (JSPS)UNSPECIFIED
Natural Sciences and Engineering Research Council of Canada (NSERC)UNSPECIFIED
Issue or Number:23
PubMed Central ID:PMC135437
Record Number:CaltechAUTHORS:UMEjbact02
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Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:4833
Deposited By: Archive Administrator
Deposited On:11 Sep 2006
Last Modified:02 Oct 2019 23:16

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