Topic
Geosmin synthase
About: Geosmin synthase is a research topic. Over the lifetime, 40 publications have been published within this topic receiving 3456 citations.
Papers
TL;DR: An efficient procedure for creating precise gene replacements in the cosmid clones by using PCR targeting and λ-Red-mediated recombination is described, which is used successfully by >20 researchers to mutate around 100 Streptomyces genes.
Abstract: Streptomycetes are high G+C Gram-positive, antibiotic-producing, mycelial soil bacteria. The 8.7-Mb Streptomyces coelicolor genome was previously sequenced by using an ordered library of Supercos-1 clones. Here, we describe an efficient procedure for creating precise gene replacements in the cosmid clones by using PCR targeting and λ-Red-mediated recombination. The cloned Streptomyces genes are replaced with a cassette containing a selectable antibiotic resistance and oriTRK2 for efficient transfer to Streptomyces by RP4-mediated intergeneric conjugation. Supercos-1 does not replicate in Streptomyces, but the clones readily undergo double-crossover recombination, thus creating gene replacements. The antibiotic resistance cassettes are flanked by yeast FLP recombinase target sequences for removal of the antibiotic resistance and oriTRK2 to generate unmarked, nonpolar mutations. The technique has been used successfully by >20 researchers to mutate around 100 Streptomyces genes. As an example, we describe its application to the discovery of a gene involved in the production of geosmin, the ubiquitous odor of soil. The gene, Sco6073 (cyc2), codes for a protein with two sesquiterpene synthase domains, only one of which is required for geosmin biosynthesis, probably via a germacra-1 (10) E,5E-dien-11-ol intermediate generated by the sesquiterpene synthase from farnesyl pyrophosphate.
1,512 citations
TL;DR: The majority of all biologically caused taste andodor outbreaks in drinking water characterized worldwide are caused by microbial production of (−)-geosmin [(−)-(4 S,4a S,8a R )-4,8a-dimethyl octahydronaphthalen-4a-ol] and (−)-2-methylisoborneol (2-MIB) {(1 R -exo)-1,2,7,7-tetramethylbicyclo] as mentioned in this paper.
Abstract: The majority of all biologically caused taste-and-odor outbreaks in drinking water characterized worldwide are caused by microbial production of (−)-geosmin [(−)-(4 S ,4a S ,8a R )-4,8a-dimethyloctahydronaphthalen-4a-ol] and (−)-2-methylisoborneol (2-MIB) {(1 R -exo)-1,2,7,7-tetramethylbicyclo
430 citations
TL;DR: Geosmin, an earthy-smelling substance, has been isolated from several actinomycetes and has been used to produce 1 mg per liter of whole broth from Streptomyces griseus LP-16.
Abstract: Geosmin, an earthy-smelling substance, has been isolated from several actinomycetes. Production of 1 mg per liter of whole broth was obtained from Streptomyces griseus LP-16. After preliminary separations, pure geosmin was isolated in milligram amounts by gas chromatography. Geosmin is a neutral oil, with an approximate boiling point of 270 C, which contains carbon and hydrogen, but no nitrogen. It undergoes a reaction with acid to give odorless argosmin, a neutral oil, with an approximate boiling point of 230 C, which contains only carbon and hydrogen. Specific rotation and ultraviolet- and infrared-absorbtion spectra were determined for both.
383 citations
TL;DR: It is shown that the recombinant N-terminal half of this protein catalyzes the Mg2+-dependent cyclization of FPP to germacradienol and germacrene D, while the highly homologous C-Terminal domain, previously thought to be catalytically silent, catalyzesThe N- and C-terminals of thisprotein each harbor a distinct, independently functioning active site.
Abstract: Geosmin (1) is responsible for the characteristic odor of moist soil, as well as off-flavors in drinking water and foodstuffs1,2. Geosmin is generated from farnesyl diphosphate (FPP, 2) by an enzyme that is encoded by the SCO6073 gene in the soil organism Streptomyces coelicolor A3(2) (ref. 3). We have now shown that the recombinant N-terminal half of this protein catalyzes the Mg2+-dependent cyclization of FPP to germacradienol (3) and germacrene D (4), while the highly homologous C-terminal domain, previously thought to be catalytically silent, catalyzes the Mg2+-dependent conversion of germacradienol to geosmin. Site-directed mutagenesis confirmed that the N- and C-terminal domains each harbor a distinct, independently functioning active site. A mutation in the N-terminal domain of germacradienol-geosmin synthase of a catalytically essential serine to alanine results in the conversion of FPP to a mixture of sesquiterpenes that includes an aberrant product identified as isolepidozene (6), which was previously suggested to be an enzyme-bound intermediate in the cyclization of FPP to germacradienol.
245 citations
TL;DR: The molecular method developed is a useful tool in monitoring potential cyanobacterial producers of geosmin and MIB and showed homology to terpene synthases genes of actinobacteria and proteobacteria.
149 citations
Related Topics (5)
Performance Metrics
| Year | Papers |
|---|---|
| 2021 | 6 |
| 2019 | 2 |
| 2018 | 1 |
| 2017 | 3 |
| 2016 | 3 |
| 2015 | 2 |