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Artificial domain duplication replicates evolutionary history of ketol-acid reductoisomerases

Cahn, Jackson K. B. and Brinkmann-Chen, Sabine and Buller, Andrew R. and Arnold, Frances H. (2016) Artificial domain duplication replicates evolutionary history of ketol-acid reductoisomerases. Protein Science, 25 (7). pp. 1241-1248. ISSN 0961-8368. PMCID PMC4918412. doi:10.1002/pro.2852.

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The duplication of protein structural domains has been proposed as a common mechanism for the generation of new protein folds. A particularly interesting case is the class II ketol-acid reductoisomerase (KARI), which putatively arose from an ancestral class I KARI by duplication of the C-terminal domain and corresponding loss of obligate dimerization. As a result, the class II enzymes acquired a deeply embedded figure-of-eight knot. To test this evolutionary hypothesis we constructed a novel class II KARI by duplicating the C-terminal domain of a hyperthermostable class I KARI. The new protein is monomeric, as confirmed by gel filtration and x-ray crystallography, and has the deeply-knotted class II KARI fold. Surprisingly, its catalytic activity is nearly unchanged from the parent KARI. This provides strong evidence in support of domain duplication as the mechanism for the evolution of the class II KARI fold and demonstrates the ability of domain duplication to generate topological novelty in a function-neutral manner.

Item Type:Article
Related URLs:
URLURL TypeDescription CentralArticle
Cahn, Jackson K. B.0000-0001-8849-4516
Brinkmann-Chen, Sabine0000-0002-5419-4192
Buller, Andrew R.0000-0002-9635-4844
Arnold, Frances H.0000-0002-4027-364X
Additional Information:© 2015 John Wiley & Sons, Inc. Manuscript Received: 19 October 2015. Manuscript Accepted: 1 December 2015. Accepted manuscript online: 8 December 2015. Version of record online: 21 December 2015. Issue online: 23 June 2016. We thank Dr. Jens Kaiser and Pavle Nikolovski for their continued support. The Molecular Observatory is supported by the Gordon and Betty Moore Foundation, the Beckman Institute, and the Sanofi-Aventis Bioengineering Research Program at Caltech. Research Funding: Gordon and Betty Moore Foundation - Grant Number: GBMF2809; Resnick Sustainability Institute at Caltech; Ruth Kirschstein NIH Postdoctoral Fellowship - Grant Number: F32GM110851.
Group:Resnick Sustainability Institute
Funding AgencyGrant Number
Gordon and Betty Moore FoundationGBMF2809
Resnick Sustainability InstituteUNSPECIFIED
NIH Postdoctoral FellowshipF32GM110851
Caltech Beckman InstituteUNSPECIFIED
Sanofi-Aventis Bioengineering Research ProgramUNSPECIFIED
Subject Keywords:ketol-acid reductoisomerase; domain duplication; fold evolution; knotted proteins
Issue or Number:7
PubMed Central ID:PMC4918412
Record Number:CaltechAUTHORS:20151215-081458127
Persistent URL:
Official Citation:Cahn, J. K.B., Brinkmann-Chen, S., Buller, A. R. and Arnold, F. H. (2016), Artificial domain duplication replicates evolutionary history of ketol-acid reductoisomerases. Protein Science, 25: 1241–1248. doi:10.1002/pro.2852
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:62917
Deposited By: Tony Diaz
Deposited On:15 Dec 2015 17:09
Last Modified:17 May 2022 16:24

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