Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:6.2.1.13 (acetyl-CoA synthetase)
 451 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Mitochondrial pyruvate dehydrogenase (PDH) is important in the production of lipids in oleaginous yeast, but other yeast may bypass the mitochondria (PDH bypass), converting pyruvate in the cytosol to acetaldehyde, then acetate and acetyl CoA which is further converted to lipids. Using a metabolic model based on the oleaginous yeast Yarrowia lipolytica, we found that introduction of this bypass to an oleaginous yeast should result in enhanced yield of triacylglycerol (TAG) on substrate. Trichosporon oleaginosus (formerly Cryptococcus curvatus) is an oleaginous yeast which can produce TAGs from both glucose and xylose. Based on the sequenced genome, it lacks at least one of the enzymes needed to complete the PDH bypass, acetaldehyde dehydrogenase (ALD), and may also be deficient in pyruvate decarboxylase and acetyl-CoA synthetase under production conditions. We introduced these genes to T. oleaginosus in various combinations and demonstrated that the yield of TAG on both glucose and xylose was improved, particularly at high C/N ratio. Expression of a phospholipid:diacyltransferase encoding gene in conjunction with the PDH bypass further enhanced lipid production. The yield of TAG on xylose (0.27 g/g) in the engineered strain approached the theoretical maximum yield of 0.289 g/g. Interestingly, TAG production was also enhanced compared to the control in some strains which were given only part of the bypass pathway, suggesting that these genes may contribute to alternative routes to cytoplasmic acetyl CoA. The metabolic model indicated that the improved yield of TAG on substrate in the PDH bypass was dependent on the production of NADPH by ALD. NADPH for lipid synthesis is otherwise primarily supplied by the pentose phosphate pathway (PPP). This would contribute to the greater improvement of TAG production from xylose compared to that observed from glucose when the PDH bypass was introduced, since xylose enters metabolism through the non-oxidative part of the PPP. Yield of TAG from xylose in the engineered strains (0.21-0.27 g/g) was comparable to that obtained from glucose and the highest so far reported for lipid or TAG production from xylose.
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PMID:Enhanced Triacylglycerol Production With Genetically Modified Trichosporon oleaginosus. 2997 32

The impact of mitochondrial dysfunction in epigenetics is emerging, but our understanding of this relationship and its effect on gene expression remains incomplete. We previously showed that acute mitochondrial DNA (mtDNA) loss leads to histone hypoacetylation. It remains to be defined if these changes are maintained when mitochondrial dysfunction is chronic and if they alter gene expression. To fill these gaps of knowledge, we here studied a progressive and a chronic model of mtDNA depletion using biochemical, pharmacological, genomics, and genetic assays. We show that histones are primarily hypoacetylated in both models. We link these effects to decreased histone acetyltransferase activity unrelated to changes in ATP citrate lyase, acetyl coenzyme A synthetase 2, or pyruvate dehydrogenase activities, which can be reversibly modulated by altering the mitochondrial pool of acetyl-coenzyme A. Also, we determined that the accompanying changes in histone acetylation regulate locus-specific gene expression and physiological outcomes, including the production of prostaglandins. These results may be relevant to the pathophysiology of mtDNA depletion syndromes and to understanding the effects of environmental agents that lead to physical or functional mtDNA loss.
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PMID:Mitochondrial acetyl-CoA reversibly regulates locus-specific histone acetylation and gene expression. 3073 48

O-acetylhomoserine (OAH) is a promising platform chemical for the production of l-methionine and other valuable compounds. However, the relative low titer and yield of OAH greatly limit its industrial production and cost-effective application. In this study, we successfully constructed an efficient OAH-producing strain with high titer and yield by combining protein and metabolic engineering strategies in E. coli. Initially, an OAH-producing strain was created by reconstruction of biosynthetic pathway and deletion of degradation and competitive pathways, which accumulated 1.68 g/L of OAH. Subsequently, several metabolic engineering strategies were implemented to improve the production of OAH. The pathway flux of OAH was enhanced by eliminating byproduct accumulation, increasing oxaloacetate supply and promoting the biosynthesis of precursor homoserine, resulting in a 1.79-fold increase in OAH production. Moreover, protein engineering was applied to improve the properties of the rate-limiting enzyme homoserine acetyltransferase (MetXlm) based on evolutionary conservation analysis and structure-guided engineering. The resulting triple F147L-M182I-M240A mutant of MetXlm exhibited a 12.15-fold increase in specific activity, and the optimized expression of the MetXlm mutant led to a 57.14% improvement in OAH production. Furthermore, the precursor acetyl-CoA supply and NADPH generation were also enhanced to facilitate the biosynthesis of OAH by promoting CoA biosynthesis, overexpressing heterogeneous acetyl-CoA synthetase (ACS), and introducing NADP-dependent pyruvate dehydrogenase (PDH). Finally, the engineered strain OAH-7 produced 62.7 g/L of OAH with yield and productivity values of 0.45 g/g glucose and 1.08 g/L/h, respectively, in a 7.5 L fed-batch fermenter, which was the highest OAH production ever reported.
ACS Synth Biol 2019 05 17
PMID:Combining Protein and Metabolic Engineering Strategies for High-Level Production of O-Acetylhomoserine in Escherichia coli. 3097 96


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