Branched-chain-amino-acid biosynthesis in plants: molecular cloning and characterization of the gene encoding acetohydroxy acid isomeroreductase (ketol-acid reductoisomerase) from <i>Arabidopsis thaliana</i> (thale cress)

Dumas, Renaud; Curien, Gilles; DeRose, Richard T.; Douce, Roland

doi:10.1042/bj2940821

Cited by 21 publications

(9 citation statements)

References 33 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…6) (33). This difference between these two reductoisomerases may reflect the fact that a putative Mg 2ϩ binding site (34,35) for ketol acid reductoisomerase was not conserved in the DXP reductoisomerase sequence.…”

Section: Discussionmentioning

confidence: 97%

“…In particular, a conserved motif (LGXTGSIG) in their N-terminal regions is deduced to be an NADPH-binding site. The motif is also found in the Nterminal region of ketol acid reductoisomerases isolated from Arabidopsis thaliana (35), Spinacia oleracea (36), Saccharomyces cerevisiae (37) and Neurospora crassa (34). Because the dxr gene product (DXP reductoisomerase) uses NADPH as a cofactor as well, the motif found in this enzyme could be an NADPH binding site.…”

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

A 1-deoxy-d-xylulose 5-phosphate reductoisomerase catalyzing the formation of 2-C-methyl-d-erythritol 4-phosphate in an alternative nonmevalonate pathway for terpenoid biosynthesis

Takahashi

Kuzuyama

Watanabe

et al. 1998

Proc. Natl. Acad. Sci. U.S.A.

462

344

View full text Add to dashboard Cite

Several eubacteria including Esherichia coli use an alternative nonmevalonate pathway for the biosynthesis of isopentenyl diphosphate instead of the ubiquitous mevalonate pathway. In the alternative pathway, 2-C-methyl-D-erythritol or its 4-phosphate, which is proposed to be formed from 1-deoxy-D-xylulose 5-phosphate via intramolecular rearrangement followed by reduction process, is one of the biosynthetic precursors of isopentenyl diphosphate.

show abstract

Section: Discussionmentioning

confidence: 97%

Section: Discussionmentioning

confidence: 99%

A 1-deoxy-d-xylulose 5-phosphate reductoisomerase catalyzing the formation of 2-C-methyl-d-erythritol 4-phosphate in an alternative nonmevalonate pathway for terpenoid biosynthesis

Takahashi

Kuzuyama

Watanabe

et al. 1998

Proc. Natl. Acad. Sci. U.S.A.

462

344

View full text Add to dashboard Cite

show abstract

“…Arg76 and Ser78 are in direct contact with the 2′-phosphate of NADPH. The existence of β2αB loops of varying lengths obscured sequence patterns of NADPH specificity in KARI multiple sequence alignments (1,8,15,22). To find the commonalities among KARI β2αB loops, we systematically analyzed the loop regions of the entire enzyme class (E.C.…”

Section: Resultsmentioning

confidence: 99%

General approach to reversing ketol-acid reductoisomerase cofactor dependence from NADPH to NADH

Brinkmann‐Chen

Flock

Cahn

et al. 2013

Proc. Natl. Acad. Sci. U.S.A.

105

156

View full text Add to dashboard Cite

To date, efforts to switch the cofactor specificity of oxidoreductases from nicotinamide adenine dinucleotide phosphate (NADPH) to nicotinamide adenine dinucleotide (NADH) have been made on a caseby-case basis with varying degrees of success. Here we present a straightforward recipe for altering the cofactor specificity of a class of NADPH-dependent oxidoreductases, the ketol-acid reductoisomerases (KARIs). Combining previous results for an engineered NADH-dependent variant of Escherichia coli KARI with available KARI crystal structures and a comprehensive KARI-sequence alignment, we identified key cofactor specificity determinants and used this information to construct five KARIs with reversed cofactor preference. Additional directed evolution generated two enzymes having NADH-dependent catalytic efficiencies that are greater than the wild-type enzymes with NADPH. High-resolution structures of a wild-type/variant pair reveal the molecular basis of the cofactor switch.branched-chain amino acid pathway | cofactor imbalance K etol-acid reductoisomerases (KARI; EC 1.1.1.86) are a family of nicotinamide adenine dinucleotide phosphate (NADPH)-dependent oxidoreductases that catalyze an alkyl-migration followed by a ketol-acid reduction of (S)-2-acetolactate (S2AL) and 2-aceto-2-hydroxybutyrate to yield (R)-2,3-dihydroxy-isovalerate and (R)-2,3-dihydroxy-3-methylvalerate, respectively (1), which are essential intermediates in the biosynthesis of branched-chain amino acids (BCAAs) (2, 3). The demand for these essential amino acids, used in the preparation of animal feed, human dietary supplements, and pharmaceuticals, is currently estimated to exceed 1,500 tons per year (4). In addition, the BCAA pathway has been engineered to produce fine chemicals and biofuels, including 1-butanol and isobutanol (5, 6). Under the anaerobic conditions preferred for large-scale fermentations, biosynthesis of BCAAs and other products that use this pathway is limited by the pathway's cofactor imbalance and reduced cellular production of NADPH (7,8). One approach to overcoming the cofactor imbalance is to engineer KARI to use NADH generated in glycolysis, thereby enabling anaerobic production of BCAA pathway products (7,8).Efforts to switch the cofactor specificity of oxidoreductases from NADPH to NADH have been made with varying degrees of success (8-17). The three reports of cofactor-switched KARIs (7,8,15) from two different organisms show few commonalities in terms of residues targeted for engineering. A general recipe for switching KARI cofactor specificity would allow metabolic engineers to take advantage of the natural sequence diversity of the KARI family, with concomitant diversity in properties such as expression level, pH tolerance, or thermal stability. By combining a systematic analysis of all reviewed and manually annotated [SwissProt (18)] KARIs, information from our previous work on switching the cofactor specificity of the Escherichia coli KARI (7), and available KARI structures, we have identified a subset of residues in ...

show abstract

“…This protein of about 59 kDa belongs to the class II type of this enzyme found in plants and some gram negative bacteria (Dumas et al, 1993). In the shorter class I form, found in most bacteria and fungi, 140 amino acids are missing in the N-terminal part of the C-terminal domain (Tyagi et al, 2005).…”

Section: Ketolacid Reductoisomerasementioning

confidence: 99%

Branched-Chain Amino Acid Metabolism inArabidopsis thaliana

Binder

2010

The Arabidopsis Book

188

242

View full text Add to dashboard Cite

Valine, leucine and isoleucine form the small group of branched-chain amino acids (BCAAs) classified by their small branched hydrocarbon residues. Unlike animals, plants are able to de novo synthesize these amino acids from pyruvate, 2-oxobutanoate and acetyl-CoA. In plants, biosynthesis follows the typical reaction pathways established for the formation of these amino acids in microorganisms. Val and Ile are synthesized in two parallel pathways using a single set of enzymes. The pathway to Leu branches of from the final intermediate of Val biosynthesis. The formation of this amino acid requires a three-step pathway generating a 2-oxoacid elongated by a methylene group. In Arabidopsis thaliana and other Brassicaceae, a homologous three-step pathway is also involved in Met chain elongation required for the biosynthesis of aliphatic glucosinolates, an important class of specialized metabolites in Brassicaceae. This is a prime example for the evolutionary relationship of pathways from primary and specialized metabolism. Similar to animals, plants also have the ability to degrade BCAAs. The importance of BCAA turnover has long been unclear, but now it seems apparent that the breakdown process might by relevant under certain environmental conditions. In this review, I summarize the current knowledge about BCAA metabolism, its regulation and its particular features in Arabidopsis thaliana.

show abstract

Branched-chain-amino-acid biosynthesis in plants: molecular cloning and characterization of the gene encoding acetohydroxy acid isomeroreductase (ketol-acid reductoisomerase) from Arabidopsis thaliana (thale cress)

Cited by 21 publications

References 33 publications

A 1-deoxy-d-xylulose 5-phosphate reductoisomerase catalyzing the formation of 2-C-methyl-d-erythritol 4-phosphate in an alternative nonmevalonate pathway for terpenoid biosynthesis

A 1-deoxy-d-xylulose 5-phosphate reductoisomerase catalyzing the formation of 2-C-methyl-d-erythritol 4-phosphate in an alternative nonmevalonate pathway for terpenoid biosynthesis

General approach to reversing ketol-acid reductoisomerase cofactor dependence from NADPH to NADH

Branched-Chain Amino Acid Metabolism inArabidopsis thaliana

Contact Info

Product

Resources

About