Amino Acid Exporters in Corynebacterium glutamicum

2020 ◽  
pp. 267-284
Author(s):  
Masaaki Wachi
Keyword(s):  
Amino Acid ◽  
Corynebacterium Glutamicum

scholarly journals Identification of glyA (Encoding Serine Hydroxymethyltransferase) and Its Use Together with the Exporter ThrE To Increase l-Threonine Accumulation by Corynebacterium glutamicum

2002 ◽  
Vol 68 (7) ◽  
pp. 3321-3327 ◽  
Author(s):  
Petra Simic ◽  
Juliane Willuhn ◽  
Hermann Sahm ◽  
Lothar Eggeling
Keyword(s):  
Amino Acid ◽  
Substrate Specificity ◽  
Corynebacterium Glutamicum ◽  
Serine Hydroxymethyltransferase ◽  
Acid Formation ◽  
Initial Activity ◽  
Intracellular Degradation ◽  
Cleavage Activity ◽  
Substrate Reduction

ABSTRACT l-Threonine can be made by the amino acid-producing bacterium Corynebacterium glutamicum. However, in the course of this process, some of the l-threonine is degraded to glycine. We detected an aldole cleavage activity of l-threonine in crude extracts with an activity of 2.2 nmol min−1 (mg of protein)−1. In order to discover the molecular reason for this activity, we cloned glyA, encoding serine hydroxymethyltransferase (SHMT). By using affinity-tagged glyA, SHMT was isolated and its substrate specificity was determined. The aldole cleavage activity of purified SHMT with l-threonine as the substrate was 1.3 μmol min−1 (mg of protein)−1, which was 4% of that with l-serine as substrate. Reduction of SHMT activity in vivo was obtained by placing the essential glyA gene in the chromosome under the control of P tac , making glyA expression isopropylthiogalactopyranoside dependent. In this way, the SHMT activity in an l-threonine producer was reduced to 8% of the initial activity, which led to a 41% reduction in glycine, while l-threonine was simultaneously increased by 49%. The intracellular availability of l-threonine to aldole cleavage was also reduced by overexpressing the l-threonine exporter thrE. In C. glutamicum DR-17, which overexpresses thrE, accumulation of 67 mM instead of 49 mM l-threonine was obtained. This shows that the potential for amino acid formation can be considerably improved by reducing its intracellular degradation and increasing its export.

Genome Breeding of an Amino Acid-Producing Corynebacterium glutamicum Mutant

2005 ◽  
pp. 179-190 ◽  
Author(s):  
Masato Ikeda ◽  
Junko Ohnishi ◽  
Satoshi Mitsuhashi
Keyword(s):  
Amino Acid ◽  
Corynebacterium Glutamicum

scholarly journals PII Signal Transduction Protein GlnK Alleviates Feedback Inhibition of N-Acetyl-L-Glutamate Kinase by L-Arginine in Corynebacterium glutamicum

2020 ◽  
Vol 86 (8) ◽  
Author(s):  
Meijuan Xu ◽  
Mi Tang ◽  
Jiamin Chen ◽  
Taowei Yang ◽  
Xian Zhang ◽  
...  
Keyword(s):  
Signal Transduction ◽  
Amino Acid ◽  
Glutamic Acid ◽  
Corynebacterium Glutamicum ◽  
Feedback Inhibition ◽  
Amino Acid Biosynthesis ◽  
Arginine Biosynthesis ◽  
Acid Biosynthesis ◽  
Content Type ◽  
Pii Protein

ABSTRACT PII signal transduction proteins are ubiquitous and highly conserved in bacteria, archaea, and plants and play key roles in controlling nitrogen metabolism. However, research on biological functions and regulatory targets of PII proteins remains limited. Here, we illustrated experimentally that the PII protein Corynebacterium glutamicum GlnK (CgGlnK) increased l-arginine yield when glnK was overexpressed in Corynebacterium glutamicum. Data showed that CgGlnK regulated l-arginine biosynthesis by upregulating the expression of genes of the l-arginine metabolic pathway and interacting with N-acetyl-l-glutamate kinase (CgNAGK), the rate-limiting enzyme in l-arginine biosynthesis. Further assays indicated that CgGlnK contributed to alleviation of the feedback inhibition of CgNAGK caused by l-arginine. In silico analysis of the binding interface of CgGlnK-CgNAGK suggested that the B and T loops of CgGlnK mainly interacted with C and N domains of CgNAGK. Moreover, F11, R47, and K85 of CgGlnK were identified as crucial binding sites that interact with CgNAGK via hydrophobic interaction and H bonds, and these interactions probably had a positive effect on maintaining the stability of the complex. Collectively, this study reveals PII-NAGK interaction in nonphotosynthetic microorganisms and further provides insights into the regulatory mechanism of PII on amino acid biosynthesis in corynebacteria. IMPORTANCE Corynebacteria are safe industrial producers of diverse amino acids, including l-glutamic acid and l-arginine. In this study, we showed that PII protein GlnK played an important role in l-glutamic acid and l-arginine biosynthesis in C. glutamicum. Through clarifying the molecular mechanism of CgGlnK in l-arginine biosynthesis, the novel interaction between CgGlnK and CgNAGK was revealed. The alleviation of l-arginine inhibition of CgNAGK reached approximately 48.21% by CgGlnK addition, and the semi-inhibition constant of CgNAGK increased 1.4-fold. Furthermore, overexpression of glnK in a high-yield l-arginine-producing strain and fermentation of the recombinant strain in a 5-liter bioreactor led to a remarkably increased production of l-arginine, 49.978 g/liter, which was about 22.61% higher than that of the initial strain. In conclusion, this study provides a new strategy for modifying amino acid biosynthesis in C. glutamicum.

Regulative interactions of the osmosensing C-terminal domain in the trimeric glycine betaine transporter BetP from Corynebacterium glutamicum

2009 ◽  
Vol 390 (8) ◽  
Author(s):  
Reinhard Krämer ◽  
Christine Ziegler
Keyword(s):  
Amino Acid ◽  
Corynebacterium Glutamicum ◽  
Protein Interactions ◽  
Regulation Mechanism ◽  
Protein Protein Interactions ◽  
Molecular Switching ◽  
X Ray ◽  
X Ray Crystallography ◽  
Terminal Domain ◽  
Domain Reorientation

Abstract Activation of the osmoregulated trimeric betaine transporter BetP from Corynebacterium glutamicum was shown to depend mainly on the correct folding and integrity of its 55 amino acid long, partly α-helical C-terminal domain. Reorientation of the three C-terminal domains in the BetP trimer indicates different lipid-protein and protein-protein interactions of the C-terminal domain during osmoregulation. A regulation mechanism is suggested where this domain switches the transporter from the inactive to the active state. Interpretation of recently obtained electron and X-ray crystallography data of BetP led to a structure-function based model of C-terminal molecular switching involved in osmoregulation.

Increasing l-lysine production in Corynebacterium glutamicum by engineering amino acid transporters

Amino Acids ◽  
2020 ◽  
Vol 52 (10) ◽  
pp. 1363-1374
Author(s):  
Jing Xiao ◽  
Datao Wang ◽  
Lei Wang ◽  
Yanjun Jiang ◽  
Le Xue ◽  
...  
Keyword(s):  
Amino Acid ◽  
Corynebacterium Glutamicum ◽  
Amino Acid Transporters ◽  
Lysine Production

scholarly journals Anaerobic growth and potential for amino acid production by nitrate respiration in Corynebacterium glutamicum

2007 ◽  
Vol 75 (5) ◽  
pp. 1173-1182 ◽  
Author(s):  
Seiki Takeno ◽  
Junko Ohnishi ◽  
Tomoha Komatsu ◽  
Tatsuya Masaki ◽  
Kikuo Sen ◽  
...  
Keyword(s):  
Amino Acid ◽  
Corynebacterium Glutamicum ◽  
Acid Production ◽  
Anaerobic Growth ◽  
Nitrate Respiration ◽  
Amino Acid Production
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