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DOI	10.1073/pnas.1511482112
	A distinct pathway for tetrahymanol synthesis in bacteria
	Banta A.B.; Wei J.H.; Welander P.V.
发表日期	2015
ISSN	0027-8424
起始页码	13478
结束页码	13483
卷号	112 期号:44
英文摘要	Tetrahymanol is a polycyclic triterpenoid lipid first discovered in the ciliate Tetrahymena pyriformis whose potential diagenetic product, gammacerane, is often used as a biomarker for water column stratification in ancient ecosystems. Bacteria are also a potential source of tetrahymanol, but neither the distribution of this lipid in extant bacteria nor the significance of bacterial tetrahymanol synthesis for interpreting gammacerane biosignatures is known. Here we couple comparative genomics with genetic and lipid analyses to link a protein of unknown function to tetrahymanol synthesis in bacteria. This tetrahymanol synthase (Ths) is found in a variety of bacterial genomes, including aerobic methanotrophs, nitrite-oxidizers, and sulfate-reducers, and in a subset of aquatic and terrestrial metagenomes. Thus, the potential to produce tetrahymanol is more widespread in the bacterial domain than previously thought. However, Ths is not encoded in any eukaryotic genomes, nor is it homologous to eukaryotic squalene-tetrahymanol cyclase, which catalyzes the cyclization of squalene directly to tetrahymanol. Rather, heterologous expression studies suggest that bacteria couple the cyclization of squalene to a hopene molecule by squalene-hopene cyclase with a subsequent Ths-dependent ring expansion to form tetrahymanol. Thus, bacteria and eukaryotes have evolved distinct biochemical mechanisms for producing tetrahymanol.
英文关键词	Biomarkers; Gammacerane; Methanotrophs; Sterols; Tetrahymanol
语种	英语
scopus关键词	lipid; squalene derivative; tetrahymanol synthase; triterpenoid; unclassified drug; bacterial protein; diploptene; mutase; squalene-hopene cyclase; tetrahymanol; triterpene; Article; bacterial genome; bacterium; controlled study; cyclization; Gammaproteobacteria; genetic analysis; genetic marker; genomics; heterologous expression; lipid analysis; lipogenesis; metagenome; nitrite oxidizer; nonhuman; priority journal; sulfate reducer; amino acid sequence; bacterium; biosynthesis; chemical structure; chemistry; classification; Desulfovibrio; enzymology; gas chromatography; genetic complementation; genetics; liquid chromatography; mass fragmentography; metabolism; Methylococcaceae; molecular genetics; mutation; phylogeny; sequence homology; Amino Acid Sequence; Bacteria; Bacterial Proteins; Biosynthetic Pathways; Chromatography, Gas; Chromatography, Liquid; Desulfovibrio; Gas Chromatography-Mass Spectrometry; Genetic Complementation Test; Genome, Bacterial; Intramolecular Transferases; Metagenome; Methylococcaceae; Molecular Sequence Data; Molecular Structure; Mutation; Phylogeny; Sequence Homology, Amino Acid; Triterpenes
来源期刊	Proceedings of the National Academy of Sciences of the United States of America
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/158980
作者单位	Banta, A.B., Department of Earth System Science, Stanford University, Stanford, CA 94305, United States; Wei, J.H., Department of Earth System Science, Stanford University, Stanford, CA 94305, United States; Welander, P.V., Department of Earth System Science, Stanford University, Stanford, CA 94305, United States
推荐引用方式 GB/T 7714	Banta A.B.,Wei J.H.,Welander P.V.. A distinct pathway for tetrahymanol synthesis in bacteria[J],2015,112(44).
APA	Banta A.B.,Wei J.H.,&Welander P.V..(2015).A distinct pathway for tetrahymanol synthesis in bacteria.Proceedings of the National Academy of Sciences of the United States of America,112(44).
MLA	Banta A.B.,et al."A distinct pathway for tetrahymanol synthesis in bacteria".Proceedings of the National Academy of Sciences of the United States of America 112.44(2015).