Revisiting the steady state kinetic mechanism of glutamine-dependent asparagine synthetase from Escherichia coli

Tesson, Alan R; Soper, Thomas S.; Ciustea, Mihai; Richards, Nigel G. J.

doi:10.1016/s0003-9861(03)00118-8

Cited by 38 publications

(75 citation statements)

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“…In addition, and as observed for other glutamine-dependent amidotransferases (36,72), ASNS does not catalyze ATP/PP i exchange (55). A new kinetic model has been recently developed that appears consistent with all known experimental data for the bacterial enzyme (63). Hence, in addition to suggesting that βAspAMP formation commits the enzyme to asparagine synthesis, implying that ammonia transfer from the N-terminal domain through the intramolecular tunnel is totally efficient, the model provides evidence for the hypothesis that glutamine can bind to the E.Asp.ATP ternary complex to yield a quaternary complex from which glutamate and ammonia can be released.…”

Section: Kinetic Mechanism Of Asparagine Synthetasementioning

confidence: 55%

“…In efforts to validate the computational model of the AS-B/7b active site complex, site-specific AS-B mutants were prepared in which this residue was replaced by aspartate (E348D) and alanine (E348A), and assayed for their ability to form asparagine and PP i . In contrast to wild-type AS-B, which forms these products in a 1:1 ratio (63,89), the E348D AS-B mutant formed two molecules of PP i per asparagine. In addition, the E348A AS-B mutant loses the ability to catalyze asparagine synthesis when glutamine or ammonia is the nitrogen source, although it retains significant levels of ATP pyrophosphatase activity (J.A.…”

Section: A Nanomolar Inhibitor Of Human Asparagine Synthetasementioning

confidence: 76%

“…Although this conclusion is supported by crystal structures of the BLS/CMA-AMP/PP i and BLS/DGPC/PP i complexes (53), and structural models for the AS-B/βAspAMP/PP i complex (vide infra) in which PP i is located deep in the active site cleft covered by the other ligands, PP i release is reported to occur prior to glutamine binding for Vibrio cholerae ASNS (64). Whatever the timing of product release, the latest kinetic model (63) supports the hypothesis that ASNS must bind βAspAMP with high affinity, raising the possibility that stable analogs of this intermediate might be potent ASNS inhibitors. In addition, it seems likely that the enzyme also stabilizes the transition state for addition of ammonia to βAspAMP 1 (Scheme 2).…”

Section: Kinetic Mechanism Of Asparagine Synthetasementioning

confidence: 95%

“…As a result, recent work in this area has been concerned with obtaining a detailed understanding of (a) the steady-state kinetic mechanism for glutaminedependent asparagine production (55,63,64), and (b) critical intermolecular interactions that play a role in mediating the synthesis of βAspAMP and its subsequent reaction with ammonia (Scheme 2). Although the general properties of ASNS from a variety of sources appear very similar, many different kinetic mechanisms have been proposed for their glutamine-dependent synthetase activity (65)(66)(67).…”

Section: Kinetic Mechanism Of Asparagine Synthetasementioning

confidence: 99%

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Asparagine Synthetase Chemotherapy

Richards

Kilberg

2006

Annu. Rev. Biochem.

204

221

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Modern clinical treatments of childhood acute lymphoblastic leukemia (ALL) employ enzymebased methods for depletion of blood asparagine in combination with standard chemotherapeutic agents. Significant side effects can arise in these protocols and, in many cases, patients develop drug-resistant forms of the disease that may be correlated with up-regulation of the enzyme glutamine-dependent asparagine synthetase (ASNS). Though the precise molecular mechanisms that result in the appearance of drug resistance are the subject of active study, potent ASNS inhibitors may have clinical utility in treating asparaginase-resistant forms of childhood ALL. This review provides an overview of recent developments in our understanding of (a) the structure and catalytic mechanism of ASNS, and (b) the role that ASNS may play in the onset of drug-resistant childhood ALL. In addition, the first successful, mechanism-based efforts to prepare and characterize nanomolar ASNS inhibitors are discussed, together with the implications of these studies for future efforts to develop useful drugs.

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Section: Kinetic Mechanism Of Asparagine Synthetasementioning

confidence: 55%

Section: A Nanomolar Inhibitor Of Human Asparagine Synthetasementioning

confidence: 76%

Section: Kinetic Mechanism Of Asparagine Synthetasementioning

confidence: 95%

Section: Kinetic Mechanism Of Asparagine Synthetasementioning

confidence: 99%

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Asparagine Synthetase Chemotherapy

Richards

Kilberg

2006

Annu. Rev. Biochem.

204

221

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“…It should be indicated that glutamate, aspartate, glutamine, and asparagine are interconnected in typical reactions of amino acids metabolism as indicated in Scheme 11. The transformation of 89 into 91 is catalyzed by asparagine synthetase [177,178].…”

mentioning

confidence: 99%

Biosynthesis and Biological Activity of Carbasugars

Roscales

Plumet

2016

International Journal of Carbohydrate Chemistry

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The first synthesis of carbasugars, compounds in which the ring oxygen of a monosaccharide had been replaced by a methylene moiety, was described in 1966 by Professor G. E. McCasland's group. Seven years later, the first true natural carbasugar (5a-carba-R-D-galactopyranose) was isolated from a fermentation broth of Streptomyces sp. MA-4145. In the following decades, the chemistry and biology of carbasugars have been extensively studied. Most of these compounds show interesting biological properties, especially enzymatic inhibitory activities, and, in consequence, an important number of analogues have also been prepared in the search for improved biological activities. The aim of this review is to give coverage on the progress made in two important aspects of these compounds: the elucidation of their biosynthesis and the consideration of their biological properties, including the extensively studied carbapyranoses as well as the much less studied carbafuranoses.

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Amino Acid Biosynthesis

Parker

Pratt

2010

Amino Acids, Peptides and Proteins in Organic Chemistry

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The ribosomal synthesis of proteins utilizes a family of 20 a-amino acids that are universally coded by the translation machinery; in addition, two further a-amino acids, selenocysteine and pyrrolysine, are now believed to be incorporated into proteins via ribosomal synthesis in some organisms. More than 300 other amino acid residues have been identified in proteins, but most are of restricted distribution and produced via post-translational modification of the ubiquitous protein amino acids [1]. The ribosomally encoded a-amino acids described here ultimately derive from a-keto acids by a process corresponding to reductive amination. The most important biosynthetic distinction relates to whether appropriate carbon skeletons are pre-existing in basic metabolism or whether they have to be synthesized de novo and this division underpins the structure of this chapter.There are a small number of a-keto acids ubiquitously found in core metabolism, notably pyruvate (and a related 3-phosphoglycerate derivative from glycolysis), together with two components of the tricarboxylic acid cycle (TCA), oxaloacetate and a-ketoglutarate (a-KG). These building blocks ultimately provide the carbon skeletons for unbranched a-amino acids of three, four, and five carbons, respectively. a-Amino acids with shorter (glycine) or longer (lysine and pyrrolysine) straight chains are made by alternative pathways depending on the available raw materials. The strategic challenge for the biosynthesis of most straight-chain amino acids centers around two issues: how is the a-amino function introduced into the carbon skeleton and what functional group manipulations are required to generate the diversity of side-chain functionality required for the protein function?The core family of straight-chain amino acids does not provide all the functionality required for proteins. a-Amino acids with branched side-chains are used for two purposes; the primary need is related to protein structural issues. Proteins fold into well-defined three-dimensional shapes by virtue of their amphipathic nature: a significant fraction of the amino acid side-chains are of low polarity and the hydrophobic effect drives the formation of ordered structures in which these side-chains are buried away from water. In contrast to the straight-chain amino

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Revisiting the steady state kinetic mechanism of glutamine-dependent asparagine synthetase from Escherichia coli

Cited by 38 publications

References 58 publications

Asparagine Synthetase Chemotherapy

Asparagine Synthetase Chemotherapy

Biosynthesis and Biological Activity of Carbasugars

Amino Acid Biosynthesis

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