Artificial domain duplication replicates evolutionary history of ketol-acid reductoisomerases
Abstract
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.
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.Attached Files
Supplemental Material - pro2852-sup-0001-suppinfo01.pdf
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Additional details
- PMCID
- PMC4918412
- Eprint ID
- 62917
- DOI
- 10.1002/pro.2852
- Resolver ID
- CaltechAUTHORS:20151215-081458127
- Gordon and Betty Moore Foundation
- GBMF2809
- Resnick Sustainability Institute
- NIH Postdoctoral Fellowship
- F32GM110851
- Caltech Beckman Institute
- Sanofi-Aventis Bioengineering Research Program
- Created
-
2015-12-15Created from EPrint's datestamp field
- Updated
-
2022-05-17Created from EPrint's last_modified field
- Caltech groups
- Resnick Sustainability Institute