The Experts below are selected from a list of 294 Experts worldwide ranked by ideXlab platform
Yajun Yan - One of the best experts on this subject based on the ideXlab platform.
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precursor directed biosynthesis of 5 Hydroxytryptophan using metabolically engineered e coli
ACS Synthetic Biology, 2015Co-Authors: Xinxiao Sun, Yuheng Lin, Qipeng Yuan, Yajun YanAbstract:A novel biosynthetic pathway was designed and verified reversely leading to the production of 5-Hydroxytryptophan (5-HTP) from glucose. This pathway takes advantage of the relaxed substrate selectivities of relevant enzymes without employing the unstable tryptophan 5-hydroxylase. First, high-titer of 5-HTP was produced from 5-hydroxyanthranilate (5-HI) by the catalysis of E. coli TrpDCBA. Then, a novel salicylate 5-hydroxylase was used to convert the non-natural substrate anthranilate to 5-HI. After that, the production of 5-HI from glucose was achieved and optimized with modular optimization. In the end, we combined the full pathway and adopted a two-stage strategy to realize the de novo production of 5-HTP. This work demonstrated the application of enzyme promiscuity in non-natural pathway design.
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engineering bacterial phenylalanine 4 hydroxylase for microbial synthesis of human neurotransmitter precursor 5 Hydroxytryptophan
ACS Synthetic Biology, 2014Co-Authors: Yuheng Lin, Xinxiao Sun, Qipeng Yuan, Yajun YanAbstract:5-Hydroxytryptophan (5-HTP) is a drug that is clinically effective against depression, insomnia, obesity, chronic headaches, etc. It is only commercially produced by the extraction from the seeds of Griffonia simplicifolia because of a lack of synthetic methods. Here, we report the efficient microbial production of 5-HTP via combinatorial protein and metabolic engineering approaches. First, we reconstituted and screened prokaryotic phenylalanine 4-hydroxylase activity in Escherichia coli. Then, sequence- and structure-based protein engineering dramatically shifted its substrate preference, allowing for efficient conversion of tryptophan to 5-HTP. Importantly, E. coli endogenous tetrahydromonapterin (MH4) could be utilized as the coenzyme, when a foreign MH4 recycling mechanism was introduced. Whole-cell bioconversion allowed the high-level production of 5-HTP (1.1-1.2 g/L) from tryptophan in shake flasks. On this basis, metabolic engineering efforts were further made to achieve the de novo 5-HTP biosynthesis from glucose. This work not only holds great scale-up potential but also demonstrates a strategy for expanding the native metabolism of microorganisms.
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Engineering Bacterial Phenylalanine 4‑Hydroxylase for Microbial Synthesis of Human Neurotransmitter Precursor 5‑Hydroxytryptophan
2014Co-Authors: Yuheng Lin, Xinxiao Sun, Qipeng Yuan, Yajun YanAbstract:5-Hydroxytryptophan (5-HTP) is a drug that is clinically effective against depression, insomnia, obesity, chronic headaches, etc. It is only commercially produced by the extraction from the seeds of Griffonia simplicifolia because of a lack of synthetic methods. Here, we report the efficient microbial production of 5-HTP via combinatorial protein and metabolic engineering approaches. First, we reconstituted and screened prokaryotic phenylalanine 4-hydroxylase activity in Escherichia coli. Then, sequence- and structure-based protein engineering dramatically shifted its substrate preference, allowing for efficient conversion of tryptophan to 5-HTP. Importantly, E. coli endogenous tetrahydromonapterin (MH4) could be utilized as the coenzyme, when a foreign MH4 recycling mechanism was introduced. Whole-cell bioconversion allowed the high-level production of 5-HTP (1.1–1.2 g/L) from tryptophan in shake flasks. On this basis, metabolic engineering efforts were further made to achieve the de novo 5-HTP biosynthesis from glucose. This work not only holds great scale-up potential but also demonstrates a strategy for expanding the native metabolism of microorganisms
Yuheng Lin - One of the best experts on this subject based on the ideXlab platform.
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precursor directed biosynthesis of 5 Hydroxytryptophan using metabolically engineered e coli
ACS Synthetic Biology, 2015Co-Authors: Xinxiao Sun, Yuheng Lin, Qipeng Yuan, Yajun YanAbstract:A novel biosynthetic pathway was designed and verified reversely leading to the production of 5-Hydroxytryptophan (5-HTP) from glucose. This pathway takes advantage of the relaxed substrate selectivities of relevant enzymes without employing the unstable tryptophan 5-hydroxylase. First, high-titer of 5-HTP was produced from 5-hydroxyanthranilate (5-HI) by the catalysis of E. coli TrpDCBA. Then, a novel salicylate 5-hydroxylase was used to convert the non-natural substrate anthranilate to 5-HI. After that, the production of 5-HI from glucose was achieved and optimized with modular optimization. In the end, we combined the full pathway and adopted a two-stage strategy to realize the de novo production of 5-HTP. This work demonstrated the application of enzyme promiscuity in non-natural pathway design.
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engineering bacterial phenylalanine 4 hydroxylase for microbial synthesis of human neurotransmitter precursor 5 Hydroxytryptophan
ACS Synthetic Biology, 2014Co-Authors: Yuheng Lin, Xinxiao Sun, Qipeng Yuan, Yajun YanAbstract:5-Hydroxytryptophan (5-HTP) is a drug that is clinically effective against depression, insomnia, obesity, chronic headaches, etc. It is only commercially produced by the extraction from the seeds of Griffonia simplicifolia because of a lack of synthetic methods. Here, we report the efficient microbial production of 5-HTP via combinatorial protein and metabolic engineering approaches. First, we reconstituted and screened prokaryotic phenylalanine 4-hydroxylase activity in Escherichia coli. Then, sequence- and structure-based protein engineering dramatically shifted its substrate preference, allowing for efficient conversion of tryptophan to 5-HTP. Importantly, E. coli endogenous tetrahydromonapterin (MH4) could be utilized as the coenzyme, when a foreign MH4 recycling mechanism was introduced. Whole-cell bioconversion allowed the high-level production of 5-HTP (1.1-1.2 g/L) from tryptophan in shake flasks. On this basis, metabolic engineering efforts were further made to achieve the de novo 5-HTP biosynthesis from glucose. This work not only holds great scale-up potential but also demonstrates a strategy for expanding the native metabolism of microorganisms.
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Engineering Bacterial Phenylalanine 4‑Hydroxylase for Microbial Synthesis of Human Neurotransmitter Precursor 5‑Hydroxytryptophan
2014Co-Authors: Yuheng Lin, Xinxiao Sun, Qipeng Yuan, Yajun YanAbstract:5-Hydroxytryptophan (5-HTP) is a drug that is clinically effective against depression, insomnia, obesity, chronic headaches, etc. It is only commercially produced by the extraction from the seeds of Griffonia simplicifolia because of a lack of synthetic methods. Here, we report the efficient microbial production of 5-HTP via combinatorial protein and metabolic engineering approaches. First, we reconstituted and screened prokaryotic phenylalanine 4-hydroxylase activity in Escherichia coli. Then, sequence- and structure-based protein engineering dramatically shifted its substrate preference, allowing for efficient conversion of tryptophan to 5-HTP. Importantly, E. coli endogenous tetrahydromonapterin (MH4) could be utilized as the coenzyme, when a foreign MH4 recycling mechanism was introduced. Whole-cell bioconversion allowed the high-level production of 5-HTP (1.1–1.2 g/L) from tryptophan in shake flasks. On this basis, metabolic engineering efforts were further made to achieve the de novo 5-HTP biosynthesis from glucose. This work not only holds great scale-up potential but also demonstrates a strategy for expanding the native metabolism of microorganisms
Bengt Langstrom - One of the best experts on this subject based on the ideXlab platform.
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whole body 11c 5 Hydroxytryptophan positron emission tomography as a universal imaging technique for neuroendocrine tumors comparison with somatostatin receptor scintigraphy and computed tomography
The Journal of Clinical Endocrinology and Metabolism, 2005Co-Authors: Hakan Orlefors, Anders Sundin, Ulrike Garske, Claes Juhlin, Kjell Oberg, Britt Skogseid, Bengt Langstrom, Mats Bergstrom, Barbro ErikssonAbstract:Neuroendocrine tumors (NETs) can be small and situated almost anywhere throughout the body. Our objective was to investigate whether whole-body (WB) positron emission tomography (PET) with 11C-5-Hydroxytryptophan (5-HTP) can be used as a universal imaging technique for NETs and to compare this technique with established imaging methods. Forty-two consecutive patients with evidence of NET and a detected lesion on any conventional imaging (six bronchial, two foregut, 16 midgut, and two thymic carcinoids; one ectopic Cushing’s syndrome; four gastrinomas; one insulinoma; six nonfunctioning endocrine pancreatic tumors; one gastric carcinoid, one paraganglioma; and two endocrine-differentiated pancreatic carcinomas) were studied. The WB-11C-5-HTP-PET examinations were compared with WB-computed tomography (CT) and somatostatin receptor scintigraphy (SRS). Tumor lesions were imaged with PET in 95% of the patients. In 58% of the patients, PET could detect more lesions than SRS and CT and equal numbers in 34%, wher...
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low brain uptake of l 11c 5 Hydroxytryptophan in major depression a positron emission tomography study on patients and healthy volunteers
Acta Psychiatrica Scandinavica, 1991Co-Authors: H Agren, L Reibring, P Hartvig, J Tedroff, P Bjurling, Katarina Hornfeldt, Yvonne Andersson, Hans Lundqvist, Bengt LangstromAbstract:The precursor of serotonin, L-5-Hydroxytryptophan (L-5-HTP), was radiolabelled with 11C in the beta-position, yielding [beta-11C]serotonin after decarboxylation, allowing positron emission tomography studies of L-5-HTP uptake across the blood-brain barrier. We studied 8 healthy volunteers and 6 patients with histories of DSM-III major depression, 2 with repeated examinations after clinically successful treatment. We report a significantly lower uptake of [11C]5-HTP across the blood-brain barrier in depressed patients, irrespective of phase of illness. The findings emphasize that serotonin is involved in depressive pathophysiology and support earlier suggestions that the transport of 5-HTP across the blood-brain barrier is compromised in major depression.
Xinxiao Sun - One of the best experts on this subject based on the ideXlab platform.
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precursor directed biosynthesis of 5 Hydroxytryptophan using metabolically engineered e coli
ACS Synthetic Biology, 2015Co-Authors: Xinxiao Sun, Yuheng Lin, Qipeng Yuan, Yajun YanAbstract:A novel biosynthetic pathway was designed and verified reversely leading to the production of 5-Hydroxytryptophan (5-HTP) from glucose. This pathway takes advantage of the relaxed substrate selectivities of relevant enzymes without employing the unstable tryptophan 5-hydroxylase. First, high-titer of 5-HTP was produced from 5-hydroxyanthranilate (5-HI) by the catalysis of E. coli TrpDCBA. Then, a novel salicylate 5-hydroxylase was used to convert the non-natural substrate anthranilate to 5-HI. After that, the production of 5-HI from glucose was achieved and optimized with modular optimization. In the end, we combined the full pathway and adopted a two-stage strategy to realize the de novo production of 5-HTP. This work demonstrated the application of enzyme promiscuity in non-natural pathway design.
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engineering bacterial phenylalanine 4 hydroxylase for microbial synthesis of human neurotransmitter precursor 5 Hydroxytryptophan
ACS Synthetic Biology, 2014Co-Authors: Yuheng Lin, Xinxiao Sun, Qipeng Yuan, Yajun YanAbstract:5-Hydroxytryptophan (5-HTP) is a drug that is clinically effective against depression, insomnia, obesity, chronic headaches, etc. It is only commercially produced by the extraction from the seeds of Griffonia simplicifolia because of a lack of synthetic methods. Here, we report the efficient microbial production of 5-HTP via combinatorial protein and metabolic engineering approaches. First, we reconstituted and screened prokaryotic phenylalanine 4-hydroxylase activity in Escherichia coli. Then, sequence- and structure-based protein engineering dramatically shifted its substrate preference, allowing for efficient conversion of tryptophan to 5-HTP. Importantly, E. coli endogenous tetrahydromonapterin (MH4) could be utilized as the coenzyme, when a foreign MH4 recycling mechanism was introduced. Whole-cell bioconversion allowed the high-level production of 5-HTP (1.1-1.2 g/L) from tryptophan in shake flasks. On this basis, metabolic engineering efforts were further made to achieve the de novo 5-HTP biosynthesis from glucose. This work not only holds great scale-up potential but also demonstrates a strategy for expanding the native metabolism of microorganisms.
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Engineering Bacterial Phenylalanine 4‑Hydroxylase for Microbial Synthesis of Human Neurotransmitter Precursor 5‑Hydroxytryptophan
2014Co-Authors: Yuheng Lin, Xinxiao Sun, Qipeng Yuan, Yajun YanAbstract:5-Hydroxytryptophan (5-HTP) is a drug that is clinically effective against depression, insomnia, obesity, chronic headaches, etc. It is only commercially produced by the extraction from the seeds of Griffonia simplicifolia because of a lack of synthetic methods. Here, we report the efficient microbial production of 5-HTP via combinatorial protein and metabolic engineering approaches. First, we reconstituted and screened prokaryotic phenylalanine 4-hydroxylase activity in Escherichia coli. Then, sequence- and structure-based protein engineering dramatically shifted its substrate preference, allowing for efficient conversion of tryptophan to 5-HTP. Importantly, E. coli endogenous tetrahydromonapterin (MH4) could be utilized as the coenzyme, when a foreign MH4 recycling mechanism was introduced. Whole-cell bioconversion allowed the high-level production of 5-HTP (1.1–1.2 g/L) from tryptophan in shake flasks. On this basis, metabolic engineering efforts were further made to achieve the de novo 5-HTP biosynthesis from glucose. This work not only holds great scale-up potential but also demonstrates a strategy for expanding the native metabolism of microorganisms
Qipeng Yuan - One of the best experts on this subject based on the ideXlab platform.
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precursor directed biosynthesis of 5 Hydroxytryptophan using metabolically engineered e coli
ACS Synthetic Biology, 2015Co-Authors: Xinxiao Sun, Yuheng Lin, Qipeng Yuan, Yajun YanAbstract:A novel biosynthetic pathway was designed and verified reversely leading to the production of 5-Hydroxytryptophan (5-HTP) from glucose. This pathway takes advantage of the relaxed substrate selectivities of relevant enzymes without employing the unstable tryptophan 5-hydroxylase. First, high-titer of 5-HTP was produced from 5-hydroxyanthranilate (5-HI) by the catalysis of E. coli TrpDCBA. Then, a novel salicylate 5-hydroxylase was used to convert the non-natural substrate anthranilate to 5-HI. After that, the production of 5-HI from glucose was achieved and optimized with modular optimization. In the end, we combined the full pathway and adopted a two-stage strategy to realize the de novo production of 5-HTP. This work demonstrated the application of enzyme promiscuity in non-natural pathway design.
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engineering bacterial phenylalanine 4 hydroxylase for microbial synthesis of human neurotransmitter precursor 5 Hydroxytryptophan
ACS Synthetic Biology, 2014Co-Authors: Yuheng Lin, Xinxiao Sun, Qipeng Yuan, Yajun YanAbstract:5-Hydroxytryptophan (5-HTP) is a drug that is clinically effective against depression, insomnia, obesity, chronic headaches, etc. It is only commercially produced by the extraction from the seeds of Griffonia simplicifolia because of a lack of synthetic methods. Here, we report the efficient microbial production of 5-HTP via combinatorial protein and metabolic engineering approaches. First, we reconstituted and screened prokaryotic phenylalanine 4-hydroxylase activity in Escherichia coli. Then, sequence- and structure-based protein engineering dramatically shifted its substrate preference, allowing for efficient conversion of tryptophan to 5-HTP. Importantly, E. coli endogenous tetrahydromonapterin (MH4) could be utilized as the coenzyme, when a foreign MH4 recycling mechanism was introduced. Whole-cell bioconversion allowed the high-level production of 5-HTP (1.1-1.2 g/L) from tryptophan in shake flasks. On this basis, metabolic engineering efforts were further made to achieve the de novo 5-HTP biosynthesis from glucose. This work not only holds great scale-up potential but also demonstrates a strategy for expanding the native metabolism of microorganisms.
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Engineering Bacterial Phenylalanine 4‑Hydroxylase for Microbial Synthesis of Human Neurotransmitter Precursor 5‑Hydroxytryptophan
2014Co-Authors: Yuheng Lin, Xinxiao Sun, Qipeng Yuan, Yajun YanAbstract:5-Hydroxytryptophan (5-HTP) is a drug that is clinically effective against depression, insomnia, obesity, chronic headaches, etc. It is only commercially produced by the extraction from the seeds of Griffonia simplicifolia because of a lack of synthetic methods. Here, we report the efficient microbial production of 5-HTP via combinatorial protein and metabolic engineering approaches. First, we reconstituted and screened prokaryotic phenylalanine 4-hydroxylase activity in Escherichia coli. Then, sequence- and structure-based protein engineering dramatically shifted its substrate preference, allowing for efficient conversion of tryptophan to 5-HTP. Importantly, E. coli endogenous tetrahydromonapterin (MH4) could be utilized as the coenzyme, when a foreign MH4 recycling mechanism was introduced. Whole-cell bioconversion allowed the high-level production of 5-HTP (1.1–1.2 g/L) from tryptophan in shake flasks. On this basis, metabolic engineering efforts were further made to achieve the de novo 5-HTP biosynthesis from glucose. This work not only holds great scale-up potential but also demonstrates a strategy for expanding the native metabolism of microorganisms
