Differential modes of DNA binding by mismatch uracil DNA glycosylase from Escherichia coli: implications for abasic lesion processing and enzyme communication in the base excision repair pathway
Author(s)
Type
Journal Article
Abstract
Mismatch uracil DNA glycosylase (Mug) from
Escherichia coli is an initiating enzyme in the
base-excision repair pathway. As with other DNA
glycosylases, the abasic product is potentially
more harmful than the initial lesion. Since Mug is
known to bind its product tightly, inhibiting
enzyme turnover, understanding how Mug binds
DNA is of significance when considering how Mug
interacts with downstream enzymes in the baseexcision
repair pathway. We have demonstrated
differential binding modes of Mug between its substrate
and abasic DNA product using both band shift
and fluorescence anisotropy assays. Mug binds its
product cooperatively, and a stoichiometric analysis
of DNA binding, catalytic activity and saltdependence
indicates that dimer formation is of
functional significance in both catalytic activity and
product binding. This is the first report of
cooperativity in the uracil DNA glycosylase superfamily
of enzymes, and forms the basis of product
inhibition in Mug. It therefore provides a new perspective
on abasic site protection and the findings
are discussed in the context of downstream lesion
processing and enzyme communication in the base
excision repair pathway.
Escherichia coli is an initiating enzyme in the
base-excision repair pathway. As with other DNA
glycosylases, the abasic product is potentially
more harmful than the initial lesion. Since Mug is
known to bind its product tightly, inhibiting
enzyme turnover, understanding how Mug binds
DNA is of significance when considering how Mug
interacts with downstream enzymes in the baseexcision
repair pathway. We have demonstrated
differential binding modes of Mug between its substrate
and abasic DNA product using both band shift
and fluorescence anisotropy assays. Mug binds its
product cooperatively, and a stoichiometric analysis
of DNA binding, catalytic activity and saltdependence
indicates that dimer formation is of
functional significance in both catalytic activity and
product binding. This is the first report of
cooperativity in the uracil DNA glycosylase superfamily
of enzymes, and forms the basis of product
inhibition in Mug. It therefore provides a new perspective
on abasic site protection and the findings
are discussed in the context of downstream lesion
processing and enzyme communication in the base
excision repair pathway.
Date Issued
2011-04-01
Date Acceptance
2010-09-23
Citation
Nucleic Acids Research, 2011, 39 (7), pp.2593-2603
ISSN
1362-4962
Publisher
Oxford University Press (OUP)
Start Page
2593
End Page
2603
Journal / Book Title
Nucleic Acids Research
Volume
39
Issue
7
Copyright Statement
© The Author(s) 2010. Published by Oxford University Press.
This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/
by-nc/2.5), which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.
This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/
by-nc/2.5), which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.
License URL
Subjects
Science & Technology
Life Sciences & Biomedicine
Biochemistry & Molecular Biology
BIOCHEMISTRY & MOLECULAR BIOLOGY
SIMPLEX-VIRUS TYPE-1
CRYSTAL-STRUCTURE
AP-ENDONUCLEASE
8-OXOGUANINE-DNA GLYCOSYLASE
SUBSTRATE RECOGNITION
INITIAL STEPS
MECHANISM
STIMULATION
COMPLEX
SPECIFICITY
Publication Status
Published