Disease relevance of nrdB

• Up to now it was assumed that E. coli possesses only one enzyme for the synthesis of deoxyribonucleotides and only conditional lethal (temperature sensitive) mutants were isolated in nrdB [1].
• The three self-splicing introns in phage T4 (in the td, sunY and nrdB genes) (Fig. 1a) each have the conserved group I catalytic RNA core structure (Fig. 1b), out of which is looped an open reading frame [2].

High impact information on nrdB

• The td, nrdB, and sunY introns of bacteriophage T4 each contain a long open reading frame (ORF) [3].
• These ORFs are preceded by functional T4 late promoters and, in the case of the nrdB intron ORF, a functional middle promoter [3].
• The alaS promoter is located approximately 500 base pairs upstream of a single BamHI restriction endonuclease cleavage site utilized in the construction of an expression recombinant plasmid, pBS1, for the nrdB product [4].
• They start with an alanine residue, and the first 30 residues confirmed the amino acid sequence predicted from the nucleotide sequence of the nrdB gene, apart from an NH2-terminal processing removal of the initiator methionine [4].
• Protein B2 produced from pBS1 is identical to the chromosomally encoded nrdB product of E. coli as regards molecular mass on sodium dodecyl sulfate-polyacrylamide gel electrophoresis, enzyme activity, tyrosine radical content, and structure of the binuclear iron center [4].

Chemical compound and disease context of nrdB

• The results also indicated that the nrdA and nrdB genes are the only genes in E. coli that code for ribonucleoside diphosphate reductase [5].

Biological context of nrdB

• We have found a third promoter initiating a transcript at 159 nucleotides upstream from the reading frame of nrdB [6].
• Since the beta 2 subunit is known to be formed after the alpha 2 subunit, the expression of the nrdB gene determines the onset of deoxyribonucleoside triphosphate synthesis and thus of T4 DNA replication [6].
• A novel approach for isolation and mapping of intron mutations in a ribonucleotide reductase encoding gene (nrdB) of bacteriophage T4 using the white halo plaque phenotype [7].
• Expression of nrdA and nrdB genes of Escherichia coli is decreased under anaerobiosis [8].

Anatomical context of nrdB

• The number of flagella per unit cell length decreased sharply after shifting the culture temperature from 30 degrees to 40 degrees C in the following Ts mutants: ftsC108, ftsD1033, ftsE1181, ftsF1141, ftsG29, ftsZ84, parA110, dnaB42, nrdB, and dnaG [9].

Analytical, diagnostic and therapeutic context of nrdB

• By Southern blotting the insertion point was determined to be in nrdB, the structural gene for the ribonucleotide reductase subunit B2 [1].

References