3-Isopropylmalate Dehydrogenase: An NAD+ dependent enzyme that catalyzes the oxidation of 3-carboxy-2-hydroxy-4-methylpentanoate to 3-carboxy-4-methyl-2-oxopentanoate. It is involved in the biosynthesis of VALINE; LEUCINE; and ISOLEUCINE.Alcohol Oxidoreductases: A subclass of enzymes which includes all dehydrogenases acting on primary and secondary alcohols as well as hemiacetals. They are further classified according to the acceptor which can be NAD+ or NADP+ (subclass 1.1.1), cytochrome (1.1.2), oxygen (1.1.3), quinone (1.1.5), or another acceptor (1.1.99).Thermus thermophilus: A species of gram-negative, aerobic, rod-shaped bacteria found in hot springs of neutral to alkaline pH, as well as in hot-water heaters.2-Isopropylmalate Synthase: An enzyme that catalyzes the first step in the biosynthetic pathway to LEUCINE, forming isopropyl malate from acetyl-CoA and alpha-ketoisovaleric acid. This enzyme was formerly listed as EC 4.1.3.12.Thermus: Gram-negative aerobic rods found in warm water (40-79 degrees C) such as hot springs, hot water tanks, and thermally polluted rivers.Enzyme Stability: The extent to which an enzyme retains its structural conformation or its activity when subjected to storage, isolation, and purification or various other physical or chemical manipulations, including proteolytic enzymes and heat.MalatesIsocitrate Dehydrogenase: An enzyme of the oxidoreductase class that catalyzes the conversion of isocitrate and NAD+ to yield 2-ketoglutarate, carbon dioxide, and NADH. It occurs in cell mitochondria. The enzyme requires Mg2+, Mn2+; it is activated by ADP, citrate, and Ca2+, and inhibited by NADH, NADPH, and ATP. The reaction is the key rate-limiting step of the citric acid (tricarboxylic) cycle. (From Dorland, 27th ed) (The NADP+ enzyme is EC 1.1.1.42.) EC 1.1.1.41.Hot Temperature: Presence of warmth or heat or a temperature notably higher than an accustomed norm.Sulfolobus: A genus of aerobic, chemolithotrophic, coccoid ARCHAEA whose organisms are thermoacidophilic. Its cells are highly irregular in shape, often lobed, but occasionally spherical. It has worldwide distribution with organisms isolated from hot acidic soils and water. Sulfur is used as an energy source.Substrate Specificity: A characteristic feature of enzyme activity in relation to the kind of substrate on which the enzyme or catalytic molecule reacts.Molecular Sequence Data: Descriptions of specific amino acid, carbohydrate, or nucleotide sequences which have appeared in the published literature and/or are deposited in and maintained by databanks such as GENBANK, European Molecular Biology Laboratory (EMBL), National Biomedical Research Foundation (NBRF), or other sequence repositories.Escherichia coli: A species of gram-negative, facultatively anaerobic, rod-shaped bacteria (GRAM-NEGATIVE FACULTATIVELY ANAEROBIC RODS) commonly found in the lower part of the intestine of warm-blooded animals. It is usually nonpathogenic, but some strains are known to produce DIARRHEA and pyogenic infections. Pathogenic strains (virotypes) are classified by their specific pathogenic mechanisms such as toxins (ENTEROTOXIGENIC ESCHERICHIA COLI), etc.Amino Acid Sequence: The order of amino acids as they occur in a polypeptide chain. This is referred to as the primary structure of proteins. It is of fundamental importance in determining PROTEIN CONFORMATION.Mutagenesis, Site-Directed: Genetically engineered MUTAGENESIS at a specific site in the DNA molecule that introduces a base substitution, or an insertion or deletion.Protein Denaturation: Disruption of the non-covalent bonds and/or disulfide bonds responsible for maintaining the three-dimensional shape and activity of the native protein.L-Lactate Dehydrogenase: A tetrameric enzyme that, along with the coenzyme NAD+, catalyzes the interconversion of LACTATE and PYRUVATE. In vertebrates, genes for three different subunits (LDH-A, LDH-B and LDH-C) exist.Crystallography, X-Ray: The study of crystal structure using X-RAY DIFFRACTION techniques. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)Models, Molecular: Models used experimentally or theoretically to study molecular shape, electronic properties, or interactions; includes analogous molecules, computer-generated graphics, and mechanical structures.Sequence Alignment: The arrangement of two or more amino acid or base sequences from an organism or organisms in such a way as to align areas of the sequences sharing common properties. The degree of relatedness or homology between the sequences is predicted computationally or statistically based on weights assigned to the elements aligned between the sequences. This in turn can serve as a potential indicator of the genetic relatedness between the organisms.Protein Conformation: The characteristic 3-dimensional shape of a protein, including the secondary, supersecondary (motifs), tertiary (domains) and quaternary structure of the peptide chain. PROTEIN STRUCTURE, QUATERNARY describes the conformation assumed by multimeric proteins (aggregates of more than one polypeptide chain).Cloning, Molecular: The insertion of recombinant DNA molecules from prokaryotic and/or eukaryotic sources into a replicating vehicle, such as a plasmid or virus vector, and the introduction of the resultant hybrid molecules into recipient cells without altering the viability of those cells.Alcohol Dehydrogenase: A zinc-containing enzyme which oxidizes primary and secondary alcohols or hemiacetals in the presence of NAD. In alcoholic fermentation, it catalyzes the final step of reducing an aldehyde to an alcohol in the presence of NADH and hydrogen.Bacillus subtilis: A species of gram-positive bacteria that is a common soil and water saprophyte.Base Sequence: The sequence of PURINES and PYRIMIDINES in nucleic acids and polynucleotides. It is also called nucleotide sequence.Kinetics: The rate dynamics in chemical or physical systems.Databases, Protein: Databases containing information about PROTEINS such as AMINO ACID SEQUENCE; PROTEIN CONFORMATION; and other properties.Proteins: Linear POLYPEPTIDES that are synthesized on RIBOSOMES and may be further modified, crosslinked, cleaved, or assembled into complex proteins with several subunits. The specific sequence of AMINO ACIDS determines the shape the polypeptide will take, during PROTEIN FOLDING, and the function of the protein.Agrobacterium tumefaciens: A species of gram-negative, aerobic bacteria isolated from soil and the stems, leafs, and roots of plants. Some biotypes are pathogenic and cause the formation of PLANT TUMORS in a wide variety of higher plants. The species is a major research tool in biotechnology.Rats, Mutant Strains: Rats bearing mutant genes which are phenotypically expressed in the animals.Ascorbic Acid Deficiency: A condition due to a dietary deficiency of ascorbic acid (vitamin C), characterized by malaise, lethargy, and weakness. As the disease progresses, joints, muscles, and subcutaneous tissues may become the sites of hemorrhage. Ascorbic acid deficiency frequently develops into SCURVY in young children fed unsupplemented cow's milk exclusively during their first year. It develops also commonly in chronic alcoholism. (Cecil Textbook of Medicine, 19th ed, p1177)Plants, Genetically Modified: PLANTS, or their progeny, whose GENOME has been altered by GENETIC ENGINEERING.t-Complex Genome Region: A 20 cM region of mouse chromosome 17 that is represented by a least two HAPLOTYPES. One of the haplotypes is referred to as the t-haplotype and contains an unusual array of mutations that affect embryonic development and male fertility. The t-haplotype is maintained in the gene pool by the presence of unusual features that prevent its recombination.Transformation, Genetic: Change brought about to an organisms genetic composition by unidirectional transfer (TRANSFECTION; TRANSDUCTION, GENETIC; CONJUGATION, GENETIC, etc.) and incorporation of foreign DNA into prokaryotic or eukaryotic cells by recombination of part or all of that DNA into the cell's genome.Arabidopsis: A plant genus of the family BRASSICACEAE that contains ARABIDOPSIS PROTEINS and MADS DOMAIN PROTEINS. The species A. thaliana is used for experiments in classical plant genetics as well as molecular genetic studies in plant physiology, biochemistry, and development.Peptides: Members of the class of compounds composed of AMINO ACIDS joined together by peptide bonds between adjacent amino acids into linear, branched or cyclical structures. OLIGOPEPTIDES are composed of approximately 2-12 amino acids. Polypeptides are composed of approximately 13 or more amino acids. PROTEINS are linear polypeptides that are normally synthesized on RIBOSOMES.Manuscripts as Topic: Compositions written by hand, as one written before the invention or adoption of printing. A manuscript may also refer to a handwritten copy of an ancient author. A manuscript may be handwritten or typewritten as distinguished from a printed copy, especially the copy of a writer's work from which printed copies are made. (Webster, 3d ed)Peptide Fragments: Partial proteins formed by partial hydrolysis of complete proteins or generated through PROTEIN ENGINEERING techniques.Manuscripts, MedicalAntimicrobial Cationic Peptides: Small cationic peptides that are an important component, in most species, of early innate and induced defenses against invading microbes. In animals they are found on mucosal surfaces, within phagocytic granules, and on the surface of the body. They are also found in insects and plants. Among others, this group includes the DEFENSINS, protegrins, tachyplesins, and thionins. They displace DIVALENT CATIONS from phosphate groups of MEMBRANE LIPIDS leading to disruption of the membrane.Aspergillus flavus: A species of imperfect fungi which grows on peanuts and other plants and produces the carcinogenic substance aflatoxin. It is also used in the production of the antibiotic flavicin.Eurotiales: An order of fungi in the phylum ASCOMYCOTA characterized by the presence of well defined peridia and cleistothecial asci. Notable anamorphs (mitosporic forms) of Eurotiales include PENICILLIUM and ASPERGILLUS.Aspergillus: A genus of mitosporic fungi containing about 100 species and eleven different teleomorphs in the family Trichocomaceae.Ascomycota: A phylum of fungi which have cross-walls or septa in the mycelium. The perfect state is characterized by the formation of a saclike cell (ascus) containing ascospores. Most pathogenic fungi with a known perfect state belong to this phylum.Aflatoxins: Furano-furano-benzopyrans that are produced by ASPERGILLUS from STERIGMATOCYSTIN. They are structurally related to COUMARINS and easily oxidized to an epoxide form to become ALKYLATING AGENTS. Members of the group include AFLATOXIN B1; aflatoxin B2, aflatoxin G1, aflatoxin G2; AFLATOXIN M1; and aflatoxin M2.Sulfolobus acidocaldarius: A species of aerobic, chemolithotrophic ARCHAEA consisting of coccoid cells that utilize sulfur as an energy source. The optimum temperature for growth is 70-75 degrees C. They are isolated from acidic fields.Sulfolobus solfataricus: A species of thermoacidophilic ARCHAEA in the family Sulfolobaceae, found in volcanic areas where the temperature is about 80 degrees C and SULFUR is present.Archaea: One of the three domains of life (the others being BACTERIA and Eukarya), formerly called Archaebacteria under the taxon Bacteria, but now considered separate and distinct. They are characterized by: (1) the presence of characteristic tRNAs and ribosomal RNAs; (2) the absence of peptidoglycan cell walls; (3) the presence of ether-linked lipids built from branched-chain subunits; and (4) their occurrence in unusual habitats. While archaea resemble bacteria in morphology and genomic organization, they resemble eukarya in their method of genomic replication. The domain contains at least four kingdoms: CRENARCHAEOTA; EURYARCHAEOTA; NANOARCHAEOTA; and KORARCHAEOTA.Origin Recognition Complex: The origin recognition complex is a multi-subunit DNA-binding protein that initiates DNA REPLICATION in eukaryotes.Chromosomes, Archaeal: Structures within the nucleus of archaeal cells consisting of or containing DNA, which carry genetic information essential to the cell.Replication Origin: A unique DNA sequence of a replicon at which DNA REPLICATION is initiated and proceeds bidirectionally or unidirectionally. It contains the sites where the first separation of the complementary strands occurs, a primer RNA is synthesized, and the switch from primer RNA to DNA synthesis takes place. (Rieger et al., Glossary of Genetics: Classical and Molecular, 5th ed)DNA Replication: The process by which a DNA molecule is duplicated.Adenosine Triphosphatases: A group of enzymes which catalyze the hydrolysis of ATP. The hydrolysis reaction is usually coupled with another function such as transporting Ca(2+) across a membrane. These enzymes may be dependent on Ca(2+), Mg(2+), anions, H+, or DNA.Saccharomyces cerevisiae: A species of the genus SACCHAROMYCES, family Saccharomycetaceae, order Saccharomycetales, known as "baker's" or "brewer's" yeast. The dried form is used as a dietary supplement.Saccharomyces cerevisiae Proteins: Proteins obtained from the species SACCHAROMYCES CEREVISIAE. The function of specific proteins from this organism are the subject of intense scientific interest and have been used to derive basic understanding of the functioning similar proteins in higher eukaryotes.

Further improvement of the thermal stability of a partially stabilized Bacillus subtilis 3-isopropylmalate dehydrogenase variant by random and site-directed mutagenesis. (1/111)

A thermostabilized mutant of Bacillus subtilis 3-isopropylmalate dehydrogenase (IPMDH) obtained in a previous study contained a set of triple amino acid substitutions. To further improve the stability of the mutant, we used a random mutagenesis technique and identified two additional thermostabilizing substitutions, Thr22-->Lys and Met256-->Val, that separately endowed the protein with further stability. We introduced the two mutations into a single enzyme molecule, thus constructing a mutant with overall quintuple mutations. Other studies have suggested that an improved hydrophobic subunit interaction and a rigid type II beta-turn play important roles in enhancing the protein stability. Based on those observations, we successively introduced amino acid substitutions into the mutant with the quintuple mutations by site-directed mutagenesis: Glu253 at the subunit interface was replaced by Leu to increase the hydrophobic interaction between the subunits; Glu112, Ser113 and Ser115 that were involved in the formation of the turn were replaced by Pro, Gly and Glu, respectively, to make the turn more rigid. The thermal stability of the mutants was determined based on remaining activity after heat treatment and first-order rate constant of thermal unfolding, which showed gradual increases in thermal stability as more mutations were included.  (+info)

Functional analysis of upstream regulating regions from the Yarrowia lipolytica XPR2 promoter. (2/111)

The XPR2 gene from Yarrowia lipolytica encodes an inducible alkaline extracellular protease. Its complex regulation involves pH, carbon, nitrogen and peptones. Two previously identified upstream activating sequence (UAS) regions were analysed in a reporter system, outside the XPR2 context. Fragments from the UAS regions were inserted upstream of a minimal LEU2 promoter directing the expression of a reporter gene. The activity of the hybrid promoters was assessed following integration into the Y. lipolytica genome. This study confirmed the presence of two UASs composed of several interacting elements. Within the distal UAS (UAS1), a TUF/RAP1 binding site exhibited a UAS activity, which was enhanced by the presence of two adjacent repeats, overlapping sites similar to the CAR1 upstream repressing sequence from Saccharomyces cerevisiae. Within the proximal UAS (UAS2), the UAS activity required the interaction of both an ABF1-like binding site and a decameric repeat, containing Aspergillus nidulans PacC site consensus sequences. This decameric repeat was able to mediate repression due to carbon and/or nitrogen sources as well as pH-dependent activation. A study in the context of trans-regulatory mutations in the Y. lipolytica RIM101 gene showed that the PacC-like sites, potential binding sites for YlRim101p, were implicated in the derepression of UAS2-driven expression at neutral-alkaline pH. The in vivo response of the PacC-like decamers to external pH was dependent on the status of the pH-regulated activator YlRim101p, which is homologous to the A. nidulans PacC regulator. The carbon/nitrogen regulation imposed on the decamers was shown to be independent of YlRim101p and to override its effects.  (+info)

Escherichia coli Lrp (leucine-responsive regulatory protein) does not directly regulate expression of the leu operon promoter. (3/111)

Studies by R. Lin et al. (J. Bacteriol. 174:1948-1955, 1992) suggested that the Escherichia coli leu operon might be a member of the Lrp regulon. Their results were obtained with a leucine auxotroph; in leucine prototrophs grown in a medium lacking leucine, there was little difference in leu operon expression between lrp(+) and lrp strains. Furthermore, when leuP-lacZ transcriptional fusions that lacked the leu attenuator were used, expression from the leu promoter varied less than twofold between lrp(+) and lrp strains, irrespective of whether or not excess leucine was added to the medium. The simplest explanation of the observations of Lin et al. is that the known elevated leucine transport capacity of lrp strains (S. A. Haney et al., J. Bacteriol. 174:108-115, 1992) leads to very high intracellular levels of leucine for strains grown with leucine, resulting in the superattenuation of leu operon expression.  (+info)

Mirror image mutations reveal the significance of an intersubunit ion cluster in the stability of 3-isopropylmalate dehydrogenase. (4/111)

The comparison of the three-dimensional structures of thermophilic (Thermus thermophilus) and mesophilic (Escherichia coli) 3-isopropylmalate dehydrogenases (IPMDH, EC 1.1.1.85) suggested that the existence of extra ion pairs in the thermophilic enzyme found in the intersubunit region may be an important factor for thermostability. As a test of our assumption, glutamine 200 in the E. coli enzyme was turned into glutamate (Q200E mutant) to mimic the thermophilic enzyme at this site by creating an intersubunit ion pair which can join existing ion clusters. At the same site in the thermophilic enzyme we changed glutamate 190 into glutamine (E190Q), hereby removing the corresponding ion pair. These single amino acid replacements resulted in increased thermostability of the mesophilic and decreased thermostability of the thermophilic enzyme, as measured by spectropolarimetry and differential scanning microcalorimetry.  (+info)

Crystal structures of 3-isopropylmalate dehydrogenases with mutations at the C-terminus: crystallographic analyses of structure-stability relationships. (5/111)

Thermal stability of the Thermus thermophilus isopropylmalate dehydrogenase enzyme was substantially lost upon the deletion of three residues from the C-terminus. However, the stability was partly recovered by the addition of two, four and seven amino acid residues (called HD177, HD708 and HD711, respectively) to the C-terminal region of the truncated enzyme. Three structures of these mutant enzymes were determined by an X-ray diffraction method. All protein crystals belong to space group P2(1) and their structures were solved by a standard molecular replacement method where the original dimer structure of the A172L mutant was used as a search model. Thermal stability of these mutant enzymes is discussed based on the 3D structure with special attention to the width of the active-site groove and the minor groove, distortion of beta-sheet pillar structure and size of cavity in the domain-domain interface around the C-terminus. Our previous studies revealed that the thermal stability of isopropylmalate dehydrogenase increases when the active-site cleft is closed (the closed form). In the present study it is shown that the active-site cleft can be regulated by open-close movement of the minor groove located at the opposite side to the active-site groove on the same subunit, through a paperclip-like motion.  (+info)

Identification of enzymes homologous to isocitrate dehydrogenase that are involved in coenzyme B and leucine biosynthesis in methanoarchaea. (6/111)

Two putative Methanococcus jannaschii isocitrate dehydrogenase genes, MJ1596 and MJ0720, were cloned and overexpressed in Escherichia coli, and their gene products were tested for the ability to catalyze the NAD- and NADP-dependent oxidative decarboxylation of DL-threo-3-isopropylmalic acid, threo-isocitrate, erythro-isocitrate, and homologs of threo-isocitrate. Neither enzyme was found to use any of the isomers of isocitrate as a substrate. The protein product of the MJ1596 gene, designated AksF, catalyzed the NAD-dependent decarboxylation of intermediates in the biosynthesis of 7-mercaptoheptanoic acid, a moiety of methanoarchaeal coenzyme B (7-mercaptoheptanylthreonine phosphate). These intermediates included (-)-threo-isohomocitrate [(-)-threo-1-hydroxy-1,2, 4-butanetricarboxylic acid], (-)-threo-iso(homo)(2)citrate [(-)-threo-1-hydroxy-1,2,5-pentanetricarboxylic acid], and (-)-threo-iso(homo)(3)citrate [(-)-threo-1-hydroxy-1,2, 6-hexanetricarboxylic acid]. The protein product of MJ0720 was found to be alpha-isopropylmalate dehydrogenase (LeuB) and was found to catalyze the NAD-dependent decarboxylation of one isomer of DL-threo-isopropylmalate to 2-ketoisocaproate; thus, it is involved in the biosynthesis of leucine. The AksF enzyme proved to be thermostable, losing only 10% of its enzymatic activity after heating at 100 degrees C for 10 min, whereas the LeuB enzyme lost 50% of its enzymatic activity after heating at 80 degrees C for 10 min.  (+info)

The initial step of the thermal unfolding of 3-isopropylmalate dehydrogenase detected by the temperature-jump Laue method. (7/111)

A temperature-jump (T-jump) time-resolved X-ray crystallographic technique using the Laue method was developed to detect small, localized structural changes of proteins in crystals exposed to a temperature increase induced by laser irradiation. In a chimeric protein between thermophilic and mesophilic 3-isopropylmalate dehydrogenases (2T2M6T), the initial structural change upon T-jump to a denaturing temperature (approximately 90 degrees C) was found to be localized at a region which includes a beta-turn and a loop located between the two domains of the enzyme. A mutant, 2T2M6T-E110P/S111G/S113E, having amino acid replacements in this beta-turn region with the corresponding residues of the thermophilic enzyme, showed greater stability than the original chimera (increase of T:(m) by approximately 10 degrees C) and no T-jump-induced structural change in this region was detected by our method. These results indicate that thermal unfolding of the original chimeric enzyme, 2T2M6T, is triggered in this beta-turn region.  (+info)

Functional prediction: identification of protein orthologs and paralogs. (8/111)

Orthologs typically retain the same function in the course of evolution. Using beta-decarboxylating dehydrogenase family as a model, we demonstrate that orthologs can be confidently identified. The strategy is based on our recent findings that substitutions of only a few amino acid residues in these enzymes are sufficient to exchange substrate and coenzyme specificities. Hence, the few major specificity determinants can serve as reliable markers for determining orthologous or paralogous relationships. The power of this approach has been demonstrated by correcting similarity-based functional misassignment and discovering new genes and related pathways, and should be broadly applicable to other enzyme families.  (+info)

  • In this study, structures of 3-isopropylmalate dehydrogenase (IPMDH) from Shewanella oneidensis MR-1 were determined at about 2 Å resolution under pressures ranging from 0.1 to 650 MPa using a diamond anvil cell (DAC). (iucr.org)
  • The expression, purification and crystallization of a thermostable short-chain alcohol dehydrogenase from the archaeon T. sibiricus is reported. (iucr.org)
  • Therefore, it comes as no surprise that isolation, characterization, and engineering of thermostable enzymes, as well as the search for the determinants of thermostability, are hot spots of current research ( 2 , 3 , 9-11 ). (asm.org)
  • BCAAs are broken down effectively by dehydrogenase and decarboxylase enzymes expressed by immune cells, and are required for lymphocyte growth and proliferation and cytotoxic T lymphocyte activity. (wikipedia.org)
  • To elucidate determinants of differences in thermostability between mesophilic and psychrophilic monomeric isocitrate dehydrogenases (IDHs) from Azotobacter vinelandii ( Av IDH) and Colwellia maris ( Cm IDH), respectively, chimeric enzymes derived from the two IDHs were constructed based on the recently resolved three-dimensional structure of Av IDH, and several characteristics of the two wild-type and six chimeric IDHs were examined. (microbiologyresearch.org)
  • Analyses of the thermostability and kinetic parameters of the chimeric enzymes indicated that region 2, corresponding to domain II, and particularly region 3 located in the C-terminal part of domain I, are involved in the thermolability of Cm IDH, and that the corresponding two regions of Av IDH are important for exhibiting higher catalytic activity and affinity for isocitrate than Cm IDH. (microbiologyresearch.org)
  • The crystal structure of the photosynthetic A 4 isoform of glyceraldehyde-3-phosphate dehydrogenase from the model plant A. thaliana has been solved at 2.6 Å resolution. (iucr.org)
  • Indeed recent work has shown that even proteins with very high sequence identity can have different folds and functions [ 1 - 3 ], and therefore caution is needed in assigning functions simply by sequence homology in the absence of experimental validation. (biomedcentral.com)
  • Furthermore, we showed CaCO 3 that precipitates earlier in an experiment modifies membrane rigidity of YS11 strain via upregulation of branched chain fatty acid synthesis. (springer.com)
  • 146. McClerklin SA*, Lee SG*, Harper CP, Nwumeh R, Jez JM, Kunkel BN (2018) Indole-3-acetaldehyde dehydrogenase-dependent auxin synthesis contributes to virulence of Pseudomonas syringae strain DC 3000. (wustl.edu)
  • The analysis showed that genes commonly involved in secondary metabolism have higher expression in infected leaf tissue, including genes encoding cytochrome P450s, short-chain dehydrogenases, and oxidoreductases in the 2-oxoglutarate and Fe(II)-dependent oxygenase superfamily. (beds.ac.uk)
  • Then, we successively deleted essential genes of competing pathways for synthesis of 2,3-butanediol ( BDH1 and BDH2 ), leucine ( LEU4 and LEU9 ), pantothenate ( ECM31 ) and isoleucine ( ILV1 ) resulting in an optimized metabolic flux toward isobutanol and titers of up to 0.56 g/L (13.54 mg/g glucose). (biomedcentral.com)
  • Overexpression of IDH2, however, did not result in increasedNAD(+)-dependent isocitrate dehydrogenase activity, suggesting that both IDH1 andIDH2 subunits are required for catalytic activity. (embl.de)
  • In the most plausible scenario, prior to hydride transfer the ε-amino group of Lys185 acts as a general base in the reaction, aiding the deprotonation reaction of 3-isopropylmalate prior to hydride transfer by employing a low-barrier proton shuttle mechanism involving a water molecule. (mtak.hu)
  • 3, 137-155 (1996) REFERENCE 9 AUTHORS Fujita,N., Mori,H., Yura,T. and Ishihama,A. TITLE Systematic sequencing of the Escherichia coli genome: analysis of the 2.4-4.1 min (110,917-193,643 bp) region JOURNAL Nucleic Acids Res. (nig.ac.jp)
  • More recently, the stereo-specific isotope labeling methods of prochiral methyl groups have become available, using either regio-selectively isotope-labeled precursors or stereo-specifically 13 CH 3 -labeled amino acids. (springer.com)