Dihydrodipicolinate synthase (DHDPS) catalyses the first reaction of the (S)-lysine biosynthesis pathway in bacteria and plants. The hypothetical gene for dihydrodipicolinate synthase (dapA) of Thermoanaerobacter tengcongensis was found in a cluster containing several genes of the diaminopimelate lysine-synthesis pathway. The dapA gene was cloned in Escherichia coli, DHDPS was subsequently produced and purified to homogeneity. The T. tengcongensis DHDPS was found to be thermostable (T0.5=3 h at 90 degrees C). The specific condensation of pyruvate and (S)-aspartate-beta -semialdehyde was catalyzed optimally at 80 degrees C at pH 8.0. Enzyme kinetics were determined at 60 degrees C, as close as possible to in vivo conditions. The established kinetic parameters were in the same range as for example E. coli dihydrodipicolinate synthase. The specific activity of the T. tengcongensis DHDPS was relatively high even at 30 degrees C. Like most dihydrodipicolinate synthases known at present, the DHDPS of T. tengcongensis seems to be a tetramer. A structural model reveals that the active site is well conserved. The binding site of the allosteric inhibitor lysine appears not to be conserved, which agrees with the fact that the DHDPS of T. tengcongensis is not inhibited by lysine under physiological conditions.
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http://dx.doi.org/10.1007/s00792-008-0152-z | DOI Listing |
J Exp Bot
October 2024
Plant Stress Biology, International Centre for Genetic Engineering and Biotechnology, New Delhi, 110067, India.
Amino acids are a major source of nourishment for people living in regions where rice is a staple food. However, rice grain is deficient in essential amino acids, such as lysine. The activity of dihydrodipicolinate synthase (DHDPS) enzyme is crucial for lysine production in higher plants, but it is highly regulated through a feedback inhibition by its end product lysine, leading to its limited activity in the grain and resulting in low lysine accumulation.
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October 2024
Key Laboratory of Industrial Biotechnology, Ministry of Education, Jiangnan University, Wuxi 214122, China.
Front Plant Sci
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Botany and Microbiology Department, Faculty of Science, Beni-Suef University, Beni-Suef, Egypt.
Plant growth-promoting bacteria (PGPB) are considered a promising tool for triggering the synthesis of bioactive compounds in plants and to produce healthy foods. This study aimed to demonstrate the impact of PGPB on the growth, accumulation of primary and secondary metabolites, biological activities, and nutritional qualities of Eruca sativa (arugula), a key leafy vegetable worldwide. To this end, Jeotgalicoccus sp.
View Article and Find Full Text PDFPlanta
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Key Laboratory of Saline-Alkali Vegetation Ecology Restoration, Ministry of Education, Northeast Forestry University, Hexing Road No. 26, Xiangfang District, Harbin, 150040, Heilongjiang, China.
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Biomolecular Interaction Centre, School of Biological Sciences, University of Canterbury, Christchurch, New Zealand.
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