Reference : DNA-binding mechanism of the Escherichia coli Ada O(6)-alkylguanine-DNA alkyltransferase.
Scientific journals : Article
Life sciences : Biochemistry, biophysics & molecular biology
http://hdl.handle.net/2268/77925
DNA-binding mechanism of the Escherichia coli Ada O(6)-alkylguanine-DNA alkyltransferase.
English
Verdemato, P. E. [> > > >]
Brannigan, J. A. [> > > >]
Damblon, Christian mailto [Université de Liège - ULg > Département de chimie (sciences) > Chimie biologique structurale >]
Zuccotto, F. [> > > >]
Moody, P. C. [> > > >]
Lian, L. Y. [> > > >]
2000
Nucleic Acids Research
Oxford University Press
28
19
3710-8
Yes (verified by ORBi)
0305-1048
1362-4962
Oxford
United Kingdom
[en] Amino Acid Motifs ; Amino Acid Sequence ; Binding Sites ; Calorimetry ; DNA/chemistry/genetics/metabolism ; DNA Methylation ; DNA Repair ; DNA, Single-Stranded/chemistry/genetics/metabolism ; DNA-Binding Proteins/chemistry/metabolism ; Entropy ; Escherichia coli/enzymology ; Models, Molecular ; Molecular Sequence Data ; Mutation/genetics ; Nuclear Magnetic Resonance, Biomolecular ; Nucleic Acid Conformation ; O(6)-Methylguanine-DNA Methyltransferase/chemistry/metabolism ; Protein Binding ; Protein Structure, Secondary ; Titrimetry
[en] The C-terminal domain of the Escherichia coli Ada protein (Ada-C) aids in the maintenance of genomic integrity by efficiently repairing pre-mutagenic O:(6)-alkylguanine lesions in DNA. Structural and thermodynamic studies were carried out to obtain a model of the DNA-binding process. Nuclear magnetic resonance (NMR) studies map the DNA-binding site to helix 5, and a loop region (residues 151-160) which form the recognition helix and the 'wing' of a helix-turn-wing motif, respectively. The NMR data also suggest the absence of a large conformational change in the protein upon binding to DNA. Hence, an O:(6)-methylguanine (O:(6)meG) lesion would be inaccessible to active site nucleophile Cys146 if the modified base remained stacked within the DNA duplex. The experimentally determined DNA-binding face of Ada-C was used in combination with homology modelling, based on the catabolite activator protein, and the accepted base-flipping mechanism, to construct a model of how Ada-C binds to DNA in a productive manner. To complement the structural studies, thermodynamic data were obtained which demonstrate that binding to unmethylated DNA was entropically driven, whilst the demethylation reaction provoked an exothermic heat change. Methylation of Cys146 leads to a loss of structural integrity of the DNA-binding subdomain.
http://hdl.handle.net/2268/77925

There is no file associated with this reference.

Bookmark and Share SFX Query

All documents in ORBi are protected by a user license.