Refined Structure of Transketolase from Saccharomyces cerevisiae at 2·0 Å Resolution

Nikkola, Matti; Lindqvist, Ylva; Schneider, Günter

doi:10.1006/jmbi.1994.1299

Cited by 183 publications

(198 citation statements)

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“…structures [3,30,51,93,108,111] and site-directed mutagenesis studies [18,28,171] have revealed that selected residues within the motif anchor the diphosphate group of ThDP through the divalent cation; no motif residue interacts directly with the thiazole and pyrimidine portions of the cofactor.…”

Section: Transketolase: a Thiamin Diphosphate Dependent Enzymementioning

confidence: 99%

“…The three-dimensional structures of several ThDP-dependent enzymes have been determined; these are Saccharomyces cerevisiae transketolase (TK) [93,111], Lactobacillus plantarum pyruvate oxidase (POX) [108], S. uvarum pyruvate decarboxylase (PDC) [30], S. cerevisiae PDC [3] and Pseudomonas putida benzoylformate decarboxylase (BDC) [51]. Three distinct domains can be discerned in each of these structures.…”

Section: Transketolase: a Thiamin Diphosphate Dependent Enzymementioning

confidence: 99%

“…The three-dimensional structure of the latter enzyme [93,111] has been published (PDB accession code 1TRK) and crystallographic studies on the E. coli enzyme have commenced [94]. Homologous expression systems are established for the S. cerevisiae [155] and the E. coli [60,153] enzyme.…”

Section: Sources Of Tkmentioning

confidence: 99%

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Properties and functions of the thiamin diphosphate dependent enzyme transketolase

Schenk

Duggleby

Nixon

1998

The International Journal of Biochemistry & Cell Biology

223

164

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This review highlights recent research on the properties and functions of the enzyme transketolase, which requires thiamin diphosphate and a divalent metal ion for its activity. The transketolase-catalysed reaction is part of the pentose phosphate pathway, where transketolase appears to control the non-oxidative branch of this pathway, although the overall¯ux of labelled substrates remains controversial. Yeast transketolase is one of several thiamin diphosphate dependent enzymes whose three-dimensional structures have been determined. Together with mutational analysis these structural data have led to detailed understanding of thiamin diphosphate catalysed reactions. In the homodimer transketolase the two catalytic sites, where dihydroxyethyl groups are transferred from ketose donors to aldose acceptors, are formed at the interface between the two subunits, where the thiazole and pyrimidine rings of thiamin diphosphate are bound. Transketolase is ubiquitous and more than 30 full-length sequences are known. The encoded protein sequences contain two motifs of high homology; one common to all thiamin diphosphate-dependent enzymes and the other a unique transketolase motif. All characterised transketolases have similar kinetic and physical properties, but the mammalian enzymes are more selective in substrate utilisation than the nonmammalian representatives. Since products of the transketolase-catalysed reaction serve as precursors for a number of synthetic compounds this enzyme has been exploited for industrial applications. Putative mutant forms of transketolase, once believed to predispose to disease, have not stood up to scrutiny. However, a modi®cation of transketolase is a marker for Alzheimer's disease, and transketolase activity in erythrocytes is a measure of thiamin nutrition. The cornea contains a particularly high transketolase concentration, consistent with the proposal that pentose phosphate pathway activity has a role in the removal of light-generated radicals. #

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Section: Transketolase: a Thiamin Diphosphate Dependent Enzymementioning

confidence: 99%

Section: Transketolase: a Thiamin Diphosphate Dependent Enzymementioning

confidence: 99%

See 1 more Smart Citation

Properties and functions of the thiamin diphosphate dependent enzyme transketolase

Schenk

Duggleby

Nixon

1998

The International Journal of Biochemistry & Cell Biology

223

164

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“…Due to its central role in energy metabolism TK has been under investigation for many years. The enzyme has been isolated from various organisms, but only a few TKs, namely those from Escherichia coli [28], S. cerevisiae [9,12,15,18,33,34] and human [4,5,13,30,32], have been characterised well. A comparison between these three homologous enzymes has revealed that physicochemical properties such as the pH optimum or the stability of the activity are very similar.…”

Section: Introductionmentioning

confidence: 99%

“…A comparison between these three homologous enzymes has revealed that physicochemical properties such as the pH optimum or the stability of the activity are very similar. Previously, the three-dimensional structure of S. cerevisiae TK has been resolved to 2.0 A Ê [18] and preliminary crystallographic data on the E. coli enzyme have been published [16]. This structural information allowed the identi®cation of residues predicted to be involved in various parts of the enzyme's function, e.g.…”

Section: Introductionmentioning

confidence: 99%

Heterologous expression of human transketolase

Schenk

Duggleby

Nixon

1998

The International Journal of Biochemistry & Cell Biology

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Transketolase belongs to the family of thiamin diphosphate dependent enzymes. The aim of this study was to establish a bacterial expression system for human transketolase in order to investigate the functional characteristics of mammalian transketolases. The level of recombinant human enzyme expressed in Escherichia coli was modest. Puri®cation of recombinant transketolase and separation from the E. coli enzyme has been greatly simpli®ed by means of a non-cleavable hexa-histidine tag. The highest speci®c activity was 13.5 U/mg and the K m values were 0.27 20.02 and 0.51 20.05 mM for the substrates D-xylulose 5-phosphate and D-ribose 5-phosphate, respectively. Binding of cofactors to the apoenzyme showed the expected hysteresis. Without preincubation, the K m values for thiamin diphosphate and for Mg 2+ were, respectively, 4.120.8 and 2.5 20.4 mM, but after 1 h of preincubation these values were 85 216 nM and 0.74 20.23 mM. The kinetic constants are similar to those of the native enzyme puri®ed from human erythrocytes. Despite the modest expression level the reported system is well suited to a variety of functional studies. #

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Transketolase

Singleton

2002

Wiley Encyclopedia of Molecular Medicine

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Refined Structure of Transketolase from Saccharomyces cerevisiae at 2·0 Å Resolution

Cited by 183 publications

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Properties and functions of the thiamin diphosphate dependent enzyme transketolase

Properties and functions of the thiamin diphosphate dependent enzyme transketolase

Heterologous expression of human transketolase

Transketolase

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