title: Novel carotenoid oxidase involved in biosynthesis of 4,4'-diapolycopene dialdehyde.
abstract: Biosynthesis of C(30) carotenoids is relatively restricted in nature but has been described in Staphylococcus and in methylotrophic bacteria. We report here identification of a novel gene (crtNb) involved in conversion of 4,4'-diapolycopene to 4,4'-diapolycopene aldehyde. An aldehyde dehydrogenase gene (ald) responsible for the subsequent oxidation of 4,4'-diapolycopene aldehyde to 4,4'-diapolycopene acid was also identified in Methylomonas. CrtNb has significant sequence homology with diapophytoene desaturases (CrtN). However, data from knockout of crtNb and expression of crtNb in Escherichia coli indicated that CrtNb is not a desaturase but rather a novel carotenoid oxidase catalyzing oxidation of the terminal methyl group(s) of 4,4'-diaponeurosporene and 4,4'-diapolycopene to the corresponding terminal aldehyde. It has moderate to low activity on neurosporene and lycopene and no activity on beta-carotene or zeta-carotene. Using a combination of C(30) carotenoid synthesis genes from Staphylococcus and Methylomonas, 4,4'-diapolycopene dialdehyde was produced in E. coli as the predominant carotenoid. This C30 dialdehyde is a dark-reddish purple pigment that may have potential uses in foods and cosmetics.
authors.affiliation: Biological and Chemical Sciences and Engineering, Central Research and Development, E. I. DuPont de Nemours Inc., E328/B48, Wilmington, Deleware 19880-0328, USA.
authors.forename: Luan
authors.initials: L
authors.lastname: Tao
authors.forename: Andreas
authors.initials: A
authors.lastname: Schenzle
authors.forename: J Martin
authors.initials: JM
authors.lastname: Odom
authors.forename: Qiong
authors.initials: Q
authors.lastname: Cheng
mesh_terms: D000444:Aldehyde Dehydrogenase / Q000378:metabolism; D000447:Aldehydes / Q000378:metabolism*; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D002338:Carotenoids / Q000096:biosynthesis* / Q000737:chemistry / Q000378:metabolism*; D004926:Escherichia coli / Q000201:enzymology / Q000235:genetics; D007218:Industrial Microbiology / Q000379:methods; D000077276:Lycopene; D020620:Methylomonas / Q000201:enzymology* / Q000235:genetics; D008969:Molecular Sequence Data; D010088:Oxidoreductases / Q000235:genetics / Q000378:metabolism*; D017422:Sequence Analysis, DNA; D013379:Substrate Specificity
chemical_list: D000447:Aldehydes; D001426:Bacterial Proteins; D002338:Carotenoids; C008604:neurosporene; C091055:CrtN protein, Staphylococcus aureus; D010088:Oxidoreductases; D000444:Aldehyde Dehydrogenase; D000077276:Lycopene