Publication Date:
2010-05-21
Description:
Type II topoisomerases are required for the management of DNA tangles and supercoils, and are targets of clinical antibiotics and anti-cancer agents. These enzymes catalyse the ATP-dependent passage of one DNA duplex (the transport or T-segment) through a transient, double-stranded break in another (the gate or G-segment), navigating DNA through the protein using a set of dissociable internal interfaces, or 'gates'. For more than 20 years, it has been established that a pair of dimer-related tyrosines, together with divalent cations, catalyse G-segment cleavage. Recent efforts have proposed that strand scission relies on a 'two-metal mechanism', a ubiquitous biochemical strategy that supports vital cellular processes ranging from DNA synthesis to RNA self-splicing. Here we present the structure of the DNA-binding and cleavage core of Saccharomyces cerevisiae topoisomerase II covalently linked to DNA through its active-site tyrosine at 2.5A resolution, revealing for the first time the organization of a cleavage-competent type II topoisomerase configuration. Unexpectedly, metal-soaking experiments indicate that cleavage is catalysed by a novel variation of the classic two-metal approach. Comparative analyses extend this scheme to explain how distantly-related type IA topoisomerases cleave single-stranded DNA, unifying the cleavage mechanisms for these two essential enzyme families. The structure also highlights a hitherto undiscovered allosteric relay that actuates a molecular 'trapdoor' to prevent subunit dissociation during cleavage. This connection illustrates how an indispensable chromosome-disentangling machine auto-regulates DNA breakage to prevent the aberrant formation of mutagenic and cytotoxic genomic lesions.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2882514/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉 〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2882514/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Schmidt, Bryan H -- Burgin, Alex B -- Deweese, Joseph E -- Osheroff, Neil -- Berger, James M -- CA077373/CA/NCI NIH HHS/ -- GM033944/GM/NIGMS NIH HHS/ -- GM053960/GM/NIGMS NIH HHS/ -- GM08295/GM/NIGMS NIH HHS/ -- R01 CA077373/CA/NCI NIH HHS/ -- R01 CA077373-11S1/CA/NCI NIH HHS/ -- R01 CA077373-12/CA/NCI NIH HHS/ -- R01 GM033944/GM/NIGMS NIH HHS/ -- T32 CA009592/CA/NCI NIH HHS/ -- T32CA09592/CA/NCI NIH HHS/ -- England -- Nature. 2010 Jun 3;465(7298):641-4. doi: 10.1038/nature08974.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Molecular and Cell Biology, University of California, Berkeley, California 94720, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/20485342" target="_blank"〉PubMed〈/a〉
Keywords:
Allosteric Regulation
;
Base Sequence
;
Catalytic Domain
;
Crystallography, X-Ray
;
DNA/*chemistry/genetics/*metabolism
;
DNA Topoisomerases, Type I/*chemistry/*metabolism
;
DNA Topoisomerases, Type II/*chemistry/*metabolism
;
Kinetics
;
Models, Molecular
;
Molecular Sequence Data
;
Saccharomyces cerevisiae/*enzymology
;
Tyrosine
Print ISSN:
0028-0836
Electronic ISSN:
1476-4687
Topics:
Biology
,
Chemistry and Pharmacology
,
Medicine
,
Natural Sciences in General
,
Physics
