Impact of Malic Enzymes on Antibiotic and Triacylglycerol Production in Streptomyces coelicolor

Abstract

<jats:title>ABSTRACT</jats:title><jats:p>In this paper, we have characterized two malic enzymes (ME), SCO2951 and SCO5261, from<jats:named-content content-type="genus-species">Streptomyces coelicolor</jats:named-content>and analyzed their role in antibiotic and triacylglycerol (TAG) production. Biochemical studies have demonstrated that Sco2951 and Sco5261 genes encode NAD<jats:sup>+</jats:sup>- and NADP<jats:sup>+</jats:sup>-dependent malic enzymes, respectively. Single or double mutants in the ME-encoding genes show no effect on growth rate compared to the parental M145 strain. However, the single Sco2951 and the double Sco2951 Sco5261 mutants display a strong reduction in the production of the polyketide antibiotic actinorhodin; additionally, the Sco2951 Sco5261 mutant shows a decrease in stored TAGs during exponential growth. The lower production of actinorhodin in the double mutant occurs as a consequence of a decrease in the expression of<jats:italic>actII-ORF4</jats:italic>, the transcriptional activator of the actinorhodin gene cluster. On the other hand, the reduced TAG accumulation is not due to reduced transcript levels of fatty acid biosynthetic genes nor to changes in the amount of the precursor acetyl coenzyme A (acetyl-CoA). This mutant accumulates intermediates of the tricarboxylic acid (TCA) cycle that could alter the regulation of the actinorhodin biosynthetic pathway, suggesting that MEs are important anaplerotic enzymes that redirect C4 intermediates from the TCA cycle to maintain secondary metabolism and TAG production in<jats:named-content content-type="genus-species">Streptomyces</jats:named-content>.</jats:p>

Identification of glucose kinase‐dependent and ‐independent pathways for carbon control of primary metabolism, development and antibiotic production inStreptomyces coelicolorby quantitative proteomics

“…Other enzymes in the anaplerotic node subject to weak Glk‐dependent CCR were the two malic enzymes (SCO2951, SCO5261). Interestingly, repression of NADH generating SCO2951 (Rodriguez et al ., ) was stronger in mannitol‐grown cultures, while repression of NADPH generating SCO5261 was stronger in fructose‐grown cultures. This might reflect the need for more NADPH to produce secondary metabolites under nutrient‐limiting conditions.…”

Metagenomic and metaproteomic analyses of Accumulibacter phosphatis‐enriched floccular and granular biofilm

“…We further detected enzymes indicative of the operation of the full TCA cycle and glyoxylate shunt. The NADP-dependent malic enzyme is an important anaplerotic enzyme that redirects TCA cycle intermediates to pyruvate and provides the required NADPH for fatty acid biosynthesis (Rodriguez et al, 2012).…”

Enzyme-constrained models and omics analysis of Streptomyces coelicolor reveal metabolic changes that enhance heterologous production

“…Other approaches for host development may be more efficient. Although S. coelicolor seems to have a complex and not fully elucidated regulatory system, several studies have shown that manipulation of regulatory genes can affect production of secondary metabolites (Jones et al, 2011;Kim et al, 2003;Okamoto et al, 2003;Rodriguez et al, 2012). The complex regulation of secondary metabolite biosynthesis makes rational strain design difficult (Liu et al, 2013), but black-box approaches including random mutations and screening are still viable approaches for strain development (van den Berg et al, 2008;Crook and Alper, 2012).…”