The transformylase enzymes of de novo purine biosynthesis

Warren, Mark S.; Mattia, Karen M.; Marolewski, Ariane E.; Benkovic, Stephen J.

doi:10.1351/pac199668112029

Cited by 23 publications

(7 citation statements)

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“…Of course, due to the participation of other medium, the reactions in actual reaction may be easier than what was investigated in this paper. Our calculation is consistent with experimental results [7,25], and properly imitates the enzymatic one-carbon unit transfer reaction in organisms. This work might provide a valuable reference for further study of such fields.…”

Section: Resultssupporting

confidence: 89%

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Molecule dynamics and combined QM/MM study on one-carbon unit transfer reaction catalyzed by GAR transformylase

et al. 2005

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Both a molecule dynamic study and a combined quantum mechanics and molecule mechanics (QM/MM) study on Glycinamide ribonucleotide transformylase (GAR Tfase) catalytic mechanism are presented. The results indicate a direct one-carbon unit transfer process but not a stepwise mechanism in this reaction. The residues near the active center can fix the cofactor (N10-formyltetrahydrofolate) and GAR in proper relative positions by a H-bond network. The transition state and the minimum energy pathway are located on the potential energy surface. After all the residues (including H 2 O molecules) are removed from the system the activation energy has increased from 145.1 kJ/mol to 243.3 kJ/mol, and the formyl transfer reaction is very hard to achieve. The interactions between coenzyme, GAR and residues near the reactive center are discussed as well.

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Section: Resultssupporting

confidence: 89%

“…[7] and Ref. [25] transition state in the reaction. The bond length of C13-N12 has been elongated from an equilibrium value of 1.393Å to 1.744Å and is about to break.…”

Section: Resultsmentioning

confidence: 99%

Molecule dynamics and combined QM/MM study on one-carbon unit transfer reaction catalyzed by GAR transformylase

et al. 2005

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“…Thus, the lack of a dramatic effect on cell growth or respiration upon disruption of the genes coding for these two enzymes would suggest that protein synthesis can be initiated in S. cerevisiae mitochondria without formylation of the initiator tRNA. There are, however, several other possible explanations that need to be ruled out: (i) transport of the cytoplasmically made 10-formyl-THF into mitochondria, (ii) alternate forms of MTF which do not use 10-formyl-THF as a formyl donor (analogous to the formatedependent glycinamide ribonucleotide transformylase [56]), or (iii) alternate genes for mitochondrial MTF with no homology to MTFs identified thus far.…”

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confidence: 99%

Initiation of Protein Synthesis in Saccharomyces cerevisiae Mitochondria without Formylation of the Initiator tRNA

Holmes

Appling

et al. 2000

J Bacteriol

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Protein synthesis in eukaryotic organelles such as mitochondria and chloroplasts is widely believed to require a formylated initiator methionyl tRNA (fMet-tRNA fMet ) for initiation. Here we show that initiation of protein synthesis in yeast mitochondria can occur without formylation of the initiator methionyl-tRNA (MettRNA fMet ). The formylation reaction is catalyzed by methionyl-tRNA formyltransferase (MTF) located in mitochondria and uses N 10 -formyltetrahydrofolate (10-formyl-THF) as the formyl donor. We have studied yeast mutants carrying chromosomal disruptions of the genes encoding the mitochondrial C 1 -tetrahydrofolate (C 1 -THF) synthase (MIS1), necessary for synthesis of 10-formyl-THF, and the methionyl-tRNA formyltransferase (open reading frame YBL013W; designated FMT1). A direct analysis of mitochondrial tRNAs using gel electrophoresis systems that can separate fMet-tRNA fMet , Met-tRNA fMet , and tRNA fMet shows that there is no formylation in vivo of the mitochondrial initiator Met-tRNA in these strains. In contrast, the initiator Met-tRNA is formylated in the respective "wild-type" parental strains. In spite of the absence of fMettRNA fMet , the mutant strains exhibited normal mitochondrial protein synthesis and function, as evidenced by normal growth on nonfermentable carbon sources in rich media and normal frequencies of generation of petite colonies. The only growth phenotype observed was a longer lag time during growth on nonfermentable carbon sources in minimal media for the mis1 deletion strain but not for the fmt1 deletion strain.

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“…Purines serve as the building blocks for DNA and RNA synthesis, as an energy source for chemical reactions (ATP), in cellular redox reactions (NADH, NADPH, FAD, etc. ), and as signaling molecules in various regulatory pathways (cAMP) (1). Because cancer cells require large amounts of purines to sustain their accelerated growth, the de novo purine biosynthetic pathway has attracted considerable attention as a target for cancer chemotherapy (2).…”

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confidence: 99%

Localization of GAR transformylase in Escherichia coli and mammalian cells

Gooljarsingh¹,

Ramcharan²,

Gilroy³

et al. 2001

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

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Enzymes of the de novo purine biosynthetic pathway may form a multienzyme complex to facilitate substrate flux through the ten serial steps constituting the pathway. One likely strategy for complex formation is the use of a structural scaffold such as the cytoskeletal network or subcellular membrane of the cell to mediate protein-protein interactions. To ascertain whether this strategy pertains to the de novo purine enzymes, the localization pattern of the third purine enzyme, glycinamide ribonucleotide transformylase (GAR Tfase) was monitored in live Escherichia coli and mammalian cells. Genes encoding human as well as E. coli GAR Tfase fused with green fluorescent protein (GFP) were introduced into their respective cells with regulated expression of proteins and localization patterns monitored by using confocal fluorescence microscopy. In both instances images showed proteins to be diffused throughout the cytoplasm. Thus, GAR Tfase is not localized to an existing cellular architecture, so this device is probably not used to concentrate the members of the pathway. However, discrete clusters of the pathway may still exist throughout the cytoplasm.

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The transformylase enzymes of de novo purine biosynthesis

Abstract: Abstract

Cited by 23 publications

References 0 publications

Molecule dynamics and combined QM/MM study on one-carbon unit transfer reaction catalyzed by GAR transformylase

Molecule dynamics and combined QM/MM study on one-carbon unit transfer reaction catalyzed by GAR transformylase

Initiation of Protein Synthesis in Saccharomyces cerevisiae Mitochondria without Formylation of the Initiator tRNA

Localization of GAR transformylase in Escherichia coli and mammalian cells

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