Genome Variations of Evolved Escherichia coli ET8 With a Rhodopsin‐Based Phototrophic Metabolism. Issue 7 (26th March 2018)

• Record Type: Journal Article
• Authors: Kim, Hyun Aaron; Kim, Hyun Ju; Lee, Min Ju; Park, Jihoon; Choi, Ah Reum; Jeong, Haeyoung; Jung, Kwang‐Hwan; Kim, Pil; Lee, Sang Jun
• Is Part Of: Biotechnology journal. Volume 13:Issue 7(2018)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2018-03-26
• Subjects: adaptive laboratory evolution -- chemotroph -- kdtA‐upregulation -- galU‐disruption -- Gloeobacter rhodopsin -- phototroph; Biotechnology -- Periodicals; 660.605
• DOI: 10.1002/biot.201700497
• Languages: English
• ISSNs: 1860-6768

Abstract

Abstract : We reported that the phototrophic metabolism via plasmid‐originated Gloeobacter rhodopsin(GR)‐expression is improved in Escherichia coli ET5 harboring pKJ606‐GR by a genomic point mutation ( dgcQ C1082A ) encoding a transmembrane cell signaling protein (Microb. Cell Fact. 16:111, 2017). Another evolved descendant is isolated from the chemostat, and the genome variation of the strain named ET8 harboring pKJ606‐GR is investigated in this study. Whole genome sequencing analysis identifies a single point mutation (C3831976A) located in the non‐coding upstream region of kdtA and an IS4 insertional mutation at galU G706 without any mutations in the plasmid. ET8 strain shows enhanced kdtA transcription and no growth in the D‐galactose or lactose sole carbon sourced minimal media. Size of ET8 strain are almost identical to that of the ancestor. Phototrophic growth and proton pumping in ET8 expressing GR (ET8 + GR) are increased 1.5‐fold and threefold, respectively, compared with those in the ancestor (W3110 + GR). To verify the effects of the genomic mutations, either the kdtA‐ upregulation or the galU ‐disruption is conducted in the ancestor. Both the kdtA‐ upregulation and the galU ‐disruption result in the drastic increases of proton‐pumping. The physiological properties arising from the genomic variations of the evolved host with the new phototrophic metabolism are further discussed. Abstract : Unexpected two genomic variations led a kdtA ‐upregulation and a galU ‐disruption during an artificial evolution, and those genomic variations enabled the rhodopsin‐expressed E. coli to enhance the phototrophic properties.