title: Cloning and Functional Characterization of a Lycopene β-Cyclase from Macrophytic Red Alga Bangia fuscopurpurea.
abstract: Lycopene cyclases cyclize the open ends of acyclic lycopene (ψ,ψ-carotene) into β- or ε-ionone rings in the crucial bifurcation step of carotenoid biosynthesis. Among all carotenoid constituents, β-carotene (β,β-carotene) is found in all photosynthetic organisms, except for purple bacteria and heliobacteria, suggesting a ubiquitous distribution of lycopene β-cyclase activity in these organisms. In this work, we isolated a gene (BfLCYB) encoding a lycopene β-cyclase fromBangia fuscopurpurea, a red alga that is considered to be one of the primitive multicellular eukaryotic photosynthetic organisms and accumulates carotenoid constituents with both β- and ε-rings, including β-carotene, zeaxanthin, α-carotene (β,ε-carotene) and lutein. Functional complementation inEscherichia colidemonstrated that BfLCYB is able to catalyze cyclization of lycopene into monocyclic γ-carotene (β,ψ-carotene) and bicyclic β-carotene, and cyclization of the open end of monocyclic δ-carotene (ε,ψ-carotene) to produce α-carotene. No ε-cyclization activity was identified for BfLCYB. Sequence comparison showed that BfLCYB shares conserved domains with other functionally characterized lycopene cyclases from different organisms and belongs to a group of ancient lycopene cyclases. AlthoughB. fuscopurpureaalso synthesizes α-carotene and lutein, its enzyme-catalyzing ε-cyclization is still unknown.
authors.affiliation: State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing 210023, China. ctjsw@126.com.
authors.forename: Tian-Jun
authors.initials: TJ
authors.lastname: Cao
authors.affiliation: State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing 210023, China. hl_david@msn.com.
authors.forename: Xing-Qi
authors.initials: XQ
authors.lastname: Huang
authors.affiliation: State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing 210023, China. someoneqyy@hotmail.com.
authors.forename: Yuan-Yuan
authors.initials: YY
authors.lastname: Qu
authors.affiliation: State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing 210023, China. njcs2006@126.com.
authors.forename: Zhong
authors.initials: Z
authors.lastname: Zhuang
authors.affiliation: Jiangsu Institute of Oceanology and Marine Fisheries, Nantong 226007, China. dengyinyin@yeah.net.
authors.forename: Yin-Yin
authors.initials: YY
authors.lastname: Deng
authors.affiliation: State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing 210023, China. shanlu@nju.edu.cn.
authors.forename: Shan
authors.initials: S
authors.lastname: Lu
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D002338:Carotenoids / Q000235:genetics* / Q000378:metabolism*; D003001:Cloning, Molecular / Q000379:methods; D004926:Escherichia coli / Q000235:genetics; D019753:Intramolecular Lyases / Q000235:genetics* / Q000378:metabolism*; D000077276:Lycopene; D010788:Photosynthesis / Q000502:physiology; D010802:Phylogeny; D000461:Rhodophyta / Q000235:genetics* / Q000378:metabolism*; D065146:Zeaxanthins / Q000235:genetics / Q000378:metabolism; D019207:beta Carotene / Q000235:genetics / Q000378:metabolism
chemical_list: D065146:Zeaxanthins; D019207:beta Carotene; D002338:Carotenoids; D019753:Intramolecular Lyases; C070925:lycopene cyclase-isomerase; D000077276:Lycopene
keywords: Bangia fuscopurpurea; carotenoid; lycopene cyclase; metabolism; red algae