Disease relevance of uvrD

• UvrD (DNA helicase II) is an essential component of two major DNA repair pathways in Escherichia coli: methyl-directed mismatch repair and UvrABC-mediated nucleotide excision repair [1].
• In this study MutL is shown to enhance the unwinding activity of DNA helicase II more than 10-fold on a conventional helicase substrate in which a 35-residue oligonucleotide is annealed to a M13 circular single-stranded phage DNA under conditions where the two proteins are present at approximately molar stoichiometry with respect to the substrate [2].

High impact information on uvrD

• Here we demonstrate that although Escherichia coli DNA helicase II (UvrD) is capable of dimerization as evidenced by a positive interaction in the yeast two-hybrid system, gel filtration chromatography, and equilibrium sedimentation ultracentrifugation (Kd = 3.4 microM), the protein is active in vivo and in vitro as a monomer [3].
• A point mutation in Escherichia coli DNA helicase II renders the enzyme nonfunctional in two DNA repair pathways. Evidence for initiation of unwinding from a nick in vivo [4].
• Mutation of a highly conserved arginine in motif IV of Escherichia coli DNA helicase II results in an ATP-binding defect [5].
• The D248N protein complemented the UV-sensitive phenotype of a uvrD deletion strain to levels nearly equivalent to wild-type helicase II [6].
• To address the functional significance of motif III in Escherichia coli DNA helicase II, the conserved aspartic acid at position 248 was changed to asparagine [6].

Chemical compound and disease context of uvrD

• A site-specific lysine to methionine mutation has been engineered at the invariant Lys35 residue in the ATPase A binding site of the Escherichia coli uvrD gene encoding DNA helicase II [7].
• Site-directed mutagenesis has been employed to address the functional significance of the highly conserved aspartic and glutamic acid residues present in the Walker B (also called motif II) sequence in Escherichia coli DNA helicase II [8].

Biological context of uvrD

• The UvrD-Q251E protein failed to complement the mutator and ultraviolet light-sensitive phenotypes of a uvrD deletion strain indicating that the mutant protein is inactive in both mismatch repair and excision repair [4].
• Located between amino acids 403 and 409, alterations in the amino acid sequence DDAAFER lead to both temperature-sensitive and dominant uvrD mutations [9].
• Inhibition of DNA helicase II unwinding and ATPase activities by DNA-interacting ligands. Kinetics and specificity [10].
• Antibody against DNA helicase II was found to inhibit the replication of E. coli DNA, lambda phage DNA (during early and late phases), and ColE1 plasmid DNA during the elongation step [11].
• Kinetics of ATP hydrolysis during the DNA helicase II-promoted unwinding of duplex DNA [12].

Associations of uvrD with chemical compounds

• Two additional genes, psecoA and uvrD, border the 3' end of the cluster and are predicted to encode a coenzyme A transferase and a DNA helicase II enzyme respectively [13].

Analytical, diagnostic and therapeutic context of uvrD

• As judged by protein affinity chromatography, MutL and MutL-E32K both support formation of ternary complexes that also contain MutS and MutH or MutS and DNA helicase II [14].

References