Directed evolution of the C25 farnesylgeranyl diphosphate synthase of Aeropyrum pernix (Fgs) was carried out by error-prone PCR with an in vivo color complementation screen utilizing carotenoid biosynthetic pathway enzymes. Screening yielded 12 evolved clones with C20 geranylgeranyl diphosphate synthase activity which were isolated and characterized in order to understand better the chain elongation mechanism of this enzyme. Analysis of these mutants revealed three different mechanisms of product chain length specificity. Two mutants (A64T and A64V) have a single mutation at the 8th amino acid upstream of a conserved first aspartate-rich motif (FARM), which is involved in the mechanism for chain elongation reaction of all prenyl diphosphate synthases. One mutant (A135T) carries a single mutation at the 7th amino acid upstream of another conserved region (141GQ142), which was recently found to be another important region controlling chain elongation of a type III C20 geranylgeranyl diphosphate synthase and Escherichia coli C15 farnesyl diphosphate synthase. Finally, one mutant carrying four mutations (V84I, H88R, I177 M and M191V) is of interest. Molecular modeling, site-directed mutagenesis and in vitro assays of this mutant suggest that product chain-length distribution can be also controlled by a structural change provoked by a cooperative interaction of amino acids.
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http://dx.doi.org/10.1093/protein/gzh089 | DOI Listing |
J Biol Chem
December 2024
Roy J. Carver Department of Biochemistry, Biophysics & Molecular Biology, Iowa State University, Ames, IA 50011, USA.
The citrus scent arises from the volatile monoterpene limonene, whose cyclic nature can be viewed as a miniaturized form of the poly-cyclic sterol triterpenoids. In particular, as these rings are all formed from poly-isoprenyl precursors via carbocation cascades. However, the relevant reactions are initiated by distinct mechanisms, either lysis/ionization of an allylic diphosphate ester bond, as in limonene synthases, or protonation of a terminal olefin or epoxide, as in lanosterol synthases.
View Article and Find Full Text PDFResearch (Wash D C)
December 2024
School of Medicine and Health, Harbin Institute of Technology, Harbin 150001, China.
Living microorganisms can perform directed migration for foraging in response to a chemoattractant gradient. We report a biomimetic strategy that rotary FF-ATPase (adenosine triphosphatase)-propelled flasklike colloidal motors exhibit positive chemotaxis resembling the chemotactic behavior of bacteria. The streamlined flasklike colloidal particles are fabricated through polymerization, expansion, surface rupture, and re-polymerizing nanoemulsions composed of triblock copolymers and ribose.
View Article and Find Full Text PDFMol Metab
December 2024
Department of Molecular and Translational Medicine, University of Brescia, Brescia, Italy. Electronic address:
Zhongguo Zhong Yao Za Zhi
October 2024
Analytical and Testing Center, Anhui Dabieshan Chinese Medicine Research Institute, Anhui Engineering Research Center for Eco-agriculture of Traditional Chinese Medicine, West Anhui University Lu'an 237012, China.
UDP-rhamnose, which is synthesized under the catalysis by the rhamnose synthase(RHM), is an essential sugar donor for the synthesis of rhamnoside in plants. Based on the reported rhamnose synthase, this study screened one RHM gene(DhuRHM) from the localized gene database of Dendrobium huoshanense by sequence alignment. This gene was cloned, and then bioinformatics analysis and in vitro functional verification were carried out.
View Article and Find Full Text PDFPlant Mol Biol
December 2024
Department of Gene Function and Phenomics, National Institute of Genetics, Shizuoka, 411-8540, Japan.
Inorganic polyphosphate (polyP) is a linear polymer of phosphate that plays various roles in cells, including in phosphate and metal homeostasis. Homologs of the vacuolar transporter chaperone 4 (VTC4), catalyzing polyP synthesis in many eukaryotes, are absent in red algae, which are among the earliest divergent plant lineages. We identified homologs of polyphosphate kinase 1 (PPK1), a conserved polyP synthase in bacteria, in 42 eukaryotic genomes, including 31 species detected in this study and 12 species of red algae.
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