Lrp of Corynebacterium glutamicum controls expression of the brnFE operon encoding the export system for l-methionine and branched-chain amino acids

ABSTRACT Acetohydroxy acid synthase (AHAS), which catalyzes the key reactions in the biosynthesis pathways of branched-chain amino acids (valine, isoleucine, and leucine), is regulated by the end products of these pathways. The whole Corynebacterium glutamicum ilvBNC operon, coding for acetohydroxy acid synthase (ilvBN) and aceto hydroxy acid isomeroreductase (ilvC), was cloned in the newly constructed Escherichia coli-C. glutamicum shuttle vector pECKA (5.4 kb, Kmr). By using site-directed mutagenesis, one to three amino acid alterations (mutations M8, M11, and M13) were introduced into the small (regulatory) AHAS subunit encoded by ilvN. The activity of AHAS and its inhibition by valine, isoleucine, and leucine were measured in strains carrying the ilvBNC operon with mutations on the plasmid or the ilvNM13 mutation within the chromosome. The enzyme containing the M13 mutation was feedback resistant to all three amino acids. Different combinations of branched-chain amino acids did not inhibit wild-type AHAS to a greater extent than was measured in the presence of 5 mM valine alone (about 57%). We infer from these results that there is a single binding (allosteric) site for all three amino acids in the enzyme molecule. The strains carrying the ilvNM13 mutation in the chromosome produced more valine than their wild-type counterparts. The plasmid-free C. glutamicum ΔilvA ΔpanB ilvNM13 strain formed 90 mM valine within 48 h of cultivation in minimal medium. The same strain harboring the plasmid pECKAilvBNC produced as much as 130 mM valine under the same conditions.

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Unusual regulation of the uptake system for branched-chain amino acids in Corynebacterium glutamicum

Archives of Microbiology ◽

10.1007/bf00250275 ◽

1993 ◽

Vol 159 (2) ◽

pp. 147-152 ◽

Cited By ~ 7

Author(s):

Eckhard Boles ◽

Holger Ebbighausen ◽

Bernhard Eikmanns ◽

Reinhard Kr�mer

Keyword(s):

Amino Acids ◽

Corynebacterium Glutamicum ◽

Branched Chain Amino Acids ◽

Uptake System ◽

Branched Chain

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Generation of branched-chain amino acids resistant Corynebacterium glutamicum acetohydroxy acid synthase by site-directed mutagenesis

Biotechnology and Bioprocess Engineering ◽

10.1007/s12257-013-0843-x ◽

2014 ◽

Vol 19 (3) ◽

pp. 456-467 ◽

Cited By ~ 6

Author(s):

Yanfeng Guo ◽

Mei Han ◽

Weiliu Yan ◽

Jianzhong Xu ◽

Weiguo Zhang

Keyword(s):

Amino Acids ◽

Corynebacterium Glutamicum ◽

Branched Chain Amino Acids ◽

Site Directed Mutagenesis ◽

Directed Mutagenesis ◽

Acetohydroxy Acid Synthase ◽

Branched Chain

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Metabolic engineering of Corynebacterium glutamicum for producing branched chain amino acids

Microbial Cell Factories ◽

10.1186/s12934-021-01721-0 ◽

2021 ◽

Vol 20 (1) ◽

Author(s):

Shengzhu Yu ◽

Bo Zheng ◽

Zhenya Chen ◽

Yi-Xin Huo

Keyword(s):

Amino Acids ◽

Metabolic Engineering ◽

Corynebacterium Glutamicum ◽

Animal Feed ◽

Feedback Inhibition ◽

Value Added ◽

Branched Chain Amino Acids ◽

High Yield ◽

Acetohydroxy Acid Synthase ◽

Branched Chain

Abstract Background Branched chain amino acids (BCAAs) are widely applied in the food, pharmaceutical, and animal feed industries. Traditional chemical synthetic and enzymatic BCAAs production in vitro has been hampered by expensive raw materials, harsh reaction conditions, and environmental pollution. Microbial metabolic engineering has attracted considerable attention as an alternative method for BCAAs biosynthesis because it is environmentally friendly and delivers high yield. Main text Corynebacterium glutamicum (C. glutamicum) possesses clear genetic background and mature gene manipulation toolbox, and has been utilized as industrial host for producing BCAAs. Acetohydroxy acid synthase (AHAS) is a crucial enzyme in the BCAAs biosynthetic pathway of C. glutamicum, but feedback inhibition is a disadvantage. We therefore reviewed AHAS modifications that relieve feedback inhibition and then investigated the importance of AHAS modifications in regulating production ratios of three BCAAs. We have comprehensively summarized and discussed metabolic engineering strategies to promote BCAAs synthesis in C. glutamicum and offer solutions to the barriers associated with BCAAs biosynthesis. We also considered the future applications of strains that could produce abundant amounts of BCAAs. Conclusions Branched chain amino acids have been synthesized by engineering the metabolism of C. glutamicum. Future investigations should focus on the feedback inhibition and/or transcription attenuation mechanisms of crucial enzymes. Enzymes with substrate specificity should be developed and applied to the production of individual BCAAs. The strategies used to construct strains producing BCAAs provide guidance for the biosynthesis of other high value-added compounds.

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Transport of branched-chain amino acids in Corynebacterium glutamicum

Archives of Microbiology ◽

10.1007/bf00413136 ◽

1989 ◽

Vol 151 (3) ◽

pp. 238-244 ◽

Cited By ~ 45

Author(s):

Holger Ebbighausen ◽

Brita Weil ◽

Reinhard Kr�mer

Keyword(s):

Amino Acids ◽

Corynebacterium Glutamicum ◽

Branched Chain Amino Acids ◽

Branched Chain

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Only L-valine among branched-chain amino acids is effective in promoting the growth of the small intestinal mucosa

Gastroenterology ◽

10.1016/s0016-5085(01)83364-3 ◽

2001 ◽

Vol 120 (5) ◽

pp. A676-A676

Author(s):

T TAKAHASHI ◽

H DOI ◽

H KOMATSU ◽

K SATO ◽

O UEDA ◽

...

Keyword(s):

Amino Acids ◽

Intestinal Mucosa ◽

Branched Chain Amino Acids ◽

Small Intestinal Mucosa ◽

Small Intestinal ◽

Branched Chain

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The Weight Loss Effects of Branched Chain Amino Acids and Vitamin B6: A Randomized Controlled Trial on Obese and Overweight Women

International Journal for Vitamin and Nutrition Research ◽

10.1024/0300-9831/a000511 ◽

2018 ◽

Vol 88 (1-2) ◽

pp. 80-89 ◽

Cited By ~ 3

Author(s):

Zahra Shakibay Novin ◽

Saeed Ghavamzadeh ◽

Alireza Mehdizadeh

Keyword(s):

Amino Acids ◽

Weight Loss ◽

Body Composition ◽

Vitamin B6 ◽

Controlled Trial ◽

Density Lipoprotein ◽

Branched Chain Amino Acids ◽

Model Assessment ◽

Waist To Hip Ratio ◽

Branched Chain

Abstract. Branched chain amino acids (BCAA), with vitamin B6 have been reported to improve fat metabolism and muscle synthesis. We hypothesized that supplementation with BCAA and vitamin B6 would result in more weight loss and improve body composition and blood markers related to cardiovascular diseases. Our aim was to determine whether the mentioned supplementation would affect weight loss, body composition, and cardiovascular risk factors during weight loss intervention. To this end, we performed a placebo-controlled randomized clinical trial in 42 overweight and obese women (BMI = 25–34.9 kg/m2). Taking a four-week moderate deficit calorie diet (–500 kcal/day), participants were randomized to receive BCAA (6 g/day) with vitamin B6 (40 mg/day) or placebo. Body composition variables measured with the use of bioelectrical impedance analysis, homeostatic model assessment, and plasma insulin, Low density lipoprotein, High density lipoprotein, Total Cholesterol, Triglyceride, and fasting blood sugar were measured. The result indicated that, weight loss was not significantly affected by BCAA and vitamin B6 supplementation (–2.43 ± 1.02 kg) or placebo (–1.64 ± 1.48 kg). However, significant time × treatment interactions in waist to hip ratio (P = 0.005), left leg lean (P = 0.004) and right leg lean (P = 0.023) were observed. Overall, supplementation with BCAA and vitamin B6 could preserve legs lean and also attenuated waist to hip ratio.

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