Domain closure and action of uracil DNA glycosylase (UDG): structures of new crystal forms containing the Escherichia coli enzyme and a comparative study of the known structures involving UDG.
The structures of a new crystal form of free Escherichia coli uracil DNA glycosylase (UDG), containing four molecules in the asymmetric unit, and two forms of its complex with the proteinaceous inhibitor Ugi, containing two and four crystallographically independent complexes, have been determined. A comparison of these structures and the already known crystal structures containing UDG shows that the enzyme can be considered to be made up of two independently moving structural entities or domains. A detailed study of free and DNA-bound human enzyme strengthens this conclusion. The domains close upon binding to uracil-containing DNA, whereas they do not appear to do so upon binding to Ugi. The comparative study also shows that the mobility of the molecule involves the rigid-body movement of the domains superposed on flexibility within domains.
Molecular Biophysics Unit, Indian Institute of Science, Bangalore 560012, India.
K
K
Saikrishnan
M
M
Bidya Sagar
R
R
Ravishankar
S
S
Roy
K
K
Purnapatre
P
P
Handa
U
U
Varshney
M
M
Vijayan
D018360:Crystallography, X-Ray; D004247:DNA / Q000378:metabolism; D045647:DNA Glycosylases; D004926:Escherichia coli / Q000201:enzymology*; D006801:Humans; D066298:In Vitro Techniques; D008958:Models, Molecular; D009699:N-Glycosyl Hydrolases / Q000737:chemistry* / Q000378:metabolism; D017434:Protein Structure, Tertiary; D051981:Uracil-DNA Glycosidase
D004247:DNA; D045647:DNA Glycosylases; D009699:N-Glycosyl Hydrolases; D051981:Uracil-DNA Glycosidase