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The archaeal enzyme geranylgeranyl reductase (GGR) catalyzes hydrogenation of carbon-carbon double bonds to produce the saturated alkyl chains of the organism's unusual isoprenoid-derived cell membrane. Enzymatic reduction of isoprenoid double bonds is of considerable interest both to natural products researchers and to synthetic biologists interested in the microbial production of isoprenoid drug or biofuel molecules. Here we present crystal structures of GGR from Sulfolobus acidocaldarius, including the structure of GGR bound to geranylgeranyl pyrophosphate (GGPP). The structures are presented alongside activity data that depict the sequential reduction of GGPP to H6GGPP via the intermediates H2GGPP and H4GGPP. We then modified the enzyme to generate sequence variants that display increased rates of H6GGPP production or are able to halt the extent of reduction at H2GGPP and H4GGPP. Crystal structures of these variants not only reveal the structural bases for their altered activities; they also shed light onto the catalytic mechanism employed.
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http://dx.doi.org/10.1016/j.str.2014.05.007 | DOI Listing |
The presence of plastid-like structures in the latex of the Russian dandelion Taraxacum koksaghyz and interactions involving plastid-associated TkGGR1 with TkSRPP3, TkGGPS6 and TkLIL3 may confer TkSRPP-mediated stress tolerance. The latex of the Russian dandelion Taraxacum koksaghyz is a rich source of natural rubber (NR) but other facets of its metabolism and physiology have been largely neglected. Small rubber particle proteins (SRPPs) contribute to NR biosynthesis by stabilizing rubber particles and are also linked to stress responses.
View Article and Find Full Text PDFJ Bacteriol
April 2025
Department of Earth Systems Science, Stanford University, Stanford, California, USA.
Unlabelled: Myxococcota is a phylum of sterol-producing bacteria. They exhibit a clade depth for sterol biosynthesis unparalleled in the bacterial domain and produce sterols of a biosynthetic complexity that rivals eukaryotes. Additionally, the sterol biosynthesis pathways found in this phylum have been proposed as a potential source for sterol biosynthesis in the last eukaryotic common ancestor, lending evolutionary importance to our understanding of this pathway in Myxococcota.
View Article and Find Full Text PDFPlant J
November 2024
Research Institute for Interdisciplinary Science, Okayama University, 3-1-1 Tsushima-naka, Kita-ku, Okayama, 700-8530, Japan.
Chlorophylls a and b (Chl a and b) are involved in light harvesting, photochemical reactions, and electron transfer reactions in plants and green algae. The core complexes of the photosystems (PSI and PSII) associate with Chl a, while the peripheral antenna complexes (LHCI and LHCII) bind Chls a and b. One of the final steps of Chl biosynthesis is the conversion of geranylgeranylated Chls (Chls) to phytylated Chls by geranylgeranyl reductase (GGR).
View Article and Find Full Text PDFInt J Mol Sci
August 2024
Tea Science Research Institute, College of Horticulture, Nanjing Agricultural University, Nanjing 210095, China.
mSystems
March 2024
Department of Earth, Marine and Environmental Sciences, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA.
Unlabelled: The continental shelf of the Western Antarctic Peninsula (WAP) is a highly variable system characterized by strong cross-shelf gradients, rapid regional change, and large blooms of phytoplankton, notably diatoms. Rapid environmental changes coincide with shifts in plankton community composition and productivity, food web dynamics, and biogeochemistry. Despite the progress in identifying important environmental factors influencing plankton community composition in the WAP, the molecular basis for their survival in this oceanic region, as well as variations in species abundance, metabolism, and distribution, remains largely unresolved.
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