Back to Search
Start Over
Global Expression Profiling and Physiological Characterization of Corynebacterium glutamicum Grown in the Presence of <scp>l</scp> -Valine
- Source :
- Applied and environmental microbiology 69, 2521-2532 (2003). doi:10.1128/AEM.69.5.2521-2532.2003
- Publication Year :
- 2003
- Publisher :
- American Society for Microbiology, 2003.
-
Abstract
- Addition of l -valine (50 to 200 mM) to glucose minimal medium had no effect on the growth of wild-type Corynebacterium glutamicum ATCC 13032 but inhibited the growth of the derived valine production strain VAL1 [13032 Δ ilvA Δ panBC (pJC1 ilvBNCD )] in a concentration-dependent manner. In order to explore this strain-specific valine effect, genomewide expression profiling was performed using DNA microarrays, which showed that valine caused an increased ilvBN mRNA level in VAL1 but not in the wild type. This unexpected result was confirmed by an increased cellular level of the ilvB protein product, i.e., the large subunit of acetohydroxyacid synthase (AHAS), and by an increased AHAS activity of valine-treated VAL1 cells. The conclusion that valine caused the limitation of another branched-chain amino acid was confirmed by showing that high concentrations of l -isoleucine could relieve the valine effect on VAL1 whereas l -leucine had the same effect as valine. The valine-caused isoleucine limitation was supported by the finding that the inhibitory valine effect was linked to the ilvA deletion that results in isoleucine auxotrophy. Taken together, these results implied that the valine effect is caused by competition for uptake of isoleucine by the carrier BrnQ, which transports all branched-chained amino acids. Indeed, valine inhibition could also be relieved by supplementing VAL1 with the dipeptide isoleucyl-isoleucine, which is taken up by a dipeptide transport system rather than by BrnQ. Interestingly, addition of external valine stimulated valine production by VAL1. This effect is most probably due to a reduced carbon usage for biomass production and to the increased expression of ilvBN , indicating that AHAS activity may still be a limiting factor for valine production in the VAL1 strain.
- Subjects :
- Auxotrophy
cloning
acetohydroxy acid synthase
Biological Transport, Active
Gene Expression
Corynebacterium
Biology
Applied Microbiology and Biotechnology
nucleotide-sequence
l-isoleucine
Corynebacterium glutamicum
regulatory protein
escherichia-coli k-12
Leucine
Valine
ddc:570
RNA, Messenger
Isoleucine
chain amino-acids
Oligonucleotide Array Sequence Analysis
chemistry.chemical_classification
Ecology
Gene Expression Profiling
Wild type
Dipeptides
Physiology and Biotechnology
operon
Molecular biology
Amino acid
Acetolactate Synthase
RNA, Bacterial
Dipeptide transport
chemistry
Biochemistry
Genes, Bacterial
gene-product
biosynthesis
Gene Deletion
Food Science
Biotechnology
Subjects
Details
- ISSN :
- 10985336 and 00992240
- Volume :
- 69
- Database :
- OpenAIRE
- Journal :
- Applied and Environmental Microbiology
- Accession number :
- edsair.doi.dedup.....16379128bac7f7ffcbb58d35c79659b1
- Full Text :
- https://doi.org/10.1128/aem.69.5.2521-2532.2003