the enzyme belongs to GAT-QueC, a two-domain family with an N-terminal glutamine amidotransferase class-II domain fused to a domain homologous to QueC, the enzyme that produces preQ0. Phylogenetic distribution of aTGT, ArcS, GAT-QueC, and QueF-like in the two archaeal phyla, overview. Most crenarchaeal genomes encode a fused GAT-QueC protein or a QueF-like protein
the metabolic pathway includes the conversion of the biosynthetic intermediate, 6-carboxy-5,6,7,8-tetrahydropterin, to intermediate, 7-carboxy-7-deazaguanine, CDG, by an unusual transformation catalyzed by QueE, a member of the radical SAM enzyme superfamily. The carboxylate moiety on CDG is converted subsequently to a nitrile to yield preQ0 by QueC in an ATP-dependent reaction, in which ammonia serves as the nitrogen source. CDG may be the central precursor to all deazapurines, biosynthesis of deazapurine containing compounds in nature incorporates H2NTP, CPH4 and CDG as common intermediates
the queC (ybaX) gene product functions in the initial step of queuosine biosynthetic pathway in Escherichia coli, queuosine incorporation in tRNAs, overview
the products of four genes, queC, queD, queE, and queF, are involved in preQ1 biosynthesis with GTP as the starting material. preQ1 is transformed to Q in tRNA
the enzyme QueC produces the G+ precursor, 7-cyano-7-deazaguanine, i.e. preQ0, which is inserted into tRNA by tRNA-guanine transglycosylase before conversion into G+ by archaeosine synthase, ArcS. Gat-QueC and QueF-like families can compensate for lack of ArcS, overview
involvement of QueC at a step leading to production of preQ0, intermediate in the pathway that utilizes GTP as the starting molecule to produce queuosine, overview
the biologically relevant unit is likely to be a QueC homodimer, crystal structure. Monomer structure, overview. The Rossmann fold of the N-terminal part of QueC, in combination with the C-terminal zinc-binding motif, forms a cavity in QueC of substantial size, which is likely to be the location of substrate binding
Please wait a moment until the data is sorted. This message will disappear when the data is sorted.
CRYSTALLIZATION/commentary
ORGANISM
UNIPROT
LITERATURE
purified QueC, vapor diffusion method, 10 mg/ml protein is mixed with crystallization solution containing 25% PEG 6000, 100 mM NaCl, 10 mM 1,6 hexanediol, and 100 mM MES, pH 5.5, 1 week, X-ray diffraction structure determination and analysis at 2.95 A resolution
molecular modeling of QueC-AMP complex. Residues Q39, T119, R97, and N98 are most likely involved in ATP binding. CDG binding likely involves residues Y129 or Y187 for pi-stacking of the CDG substrate, and D125 or D131 in binding the primary and secondary amines of the substrate pyrimidine
in vitro preparation of the deazapurine nucleoside, preQ0, by the successive action of the four involved enzymes, i.e. Escherichia coli QueD, Bacillus subtilis QueE and QueC, and Streptomyces rimosus ToyM, cloning and expression in Escherichia coli strain BL21(DE3), overview
the expression of QueC from a plasmid-borne copy confers a Q+ phenotype to enzyme-deficient mutant strain Escherichia coli B105, mapping of the transposon insertion site, overview. Generation of a knockout of queC in Escherichia coli strain JE10651, a queA mutant
recombinant QueC from Escherichia coli strain BL21(DE3) by anion exchange chromatography, hydrophobic interaction chromatography, and another different step of anion exchange chromatography, followed by gel filtration
HOME
login
history
all enzymes
BRENDA home
History
6.3.4.20 7-cyano-7-deazaguanine synthase
more
top
Information
