Type II topoisomerases are a ubiquitous class of proteins that use ATP to actively transport one DNA duplex through another. This reaction is essential for supercoiling homeostasis and resolving cytotoxic chromosome tangles prior to cell division. Type II topoisomerases are also targeted by drugs that serve as frontline clinical therapies for cancer and bacterial infections. The long-term objective of this proposal is to investigate the molecular basis of type II topoisomerase function and drug inhibition. Although rough framework for the catalytic cycle of these enzymes is in place, there remain many critical questions surrounding the mechanisms by which type II topoisomerases discriminate between different topological states of DNA, undergo allosteric transitions to drive DNA transport, and are inhibited by small molecule "poisons" that stimulate DNA cleavage. Using a combination of structural, biochemical, and biophysical methods we aim to fill these gaps by: 1) Determining the structure of a "poisoned" type II topoisomerase/DNA complex, 2) Establishing how a novel DNA binding and bending domain in bacterial type II topoisomerases controls substrate selectivity and functional output, and 3) Defining the molecular mechanisms and kinetics of DNA deformations and key structural rearrangements in the topoisomerase catalytic cycle. Our proposed studies will define the physical events by which type II topoisomerases facilitate the passage of one DNA segment through another to globally control DNA topology, and by which anticancer and antibacterial inhibitors subvert enzyme function. Data resulting from such efforts broadly impact a number of important scientific fronts, from understanding the dynamics of ATP-dependent molecular machines and regulation of chromosome superstructure, to defining the physical action of anti-topoisomerase therapies and aiding drug development. PROJECT NARRATIVE: Type II topoisomerases are molecular machines that disentangle DNA, as well as validated targets for frontline antibacterial and anticancer therapies. This proposal aims to understand the biochemistry and mechanics of the topoisomerase reaction, and to determine how some of the most widely-used anti-topoisomerase drugs block enzyme function.
Type II topoisomerases are molecular machines that disentangle DNA, as well as validated targets for frontline antibacterial and anticancer therapies. This proposal aims to understand the biochemistry and mechanics of the topoisomerase reaction, and to determine how some of the most widely-used anti-topoisomerase drugs block enzyme function.
|Kranzusch, Philip J; Lee, Amy S Y; Wilson, Stephen C et al. (2014) Structure-guided reprogramming of human cGAS dinucleotide linkage specificity. Cell 158:1011-21|
|Vos, Seychelle M; Lyubimov, Artem Y; Hershey, David M et al. (2014) Direct control of type IIA topoisomerase activity by a chromosomally encoded regulatory protein. Genes Dev 28:1485-97|
|Mustaev, Arkady; Malik, Muhammad; Zhao, Xilin et al. (2014) Fluoroquinolone-gyrase-DNA complexes: two modes of drug binding. J Biol Chem 289:12300-12|
|Vos, Seychelle M; Stewart, Nichole K; Oakley, Martha G et al. (2013) Structural basis for the MukB-topoisomerase IV interaction and its functional implications in vivo. EMBO J 32:2950-62|
|Vos, Seychelle M; Lee, Imsang; Berger, James M (2013) Distinct regions of the Escherichia coli ParC C-terminal domain are required for substrate discrimination by topoisomerase IV. J Mol Biol 425:3029-45|
|Tretter, Elsa M; Berger, James M (2012) Mechanisms for defining supercoiling set point of DNA gyrase orthologs: II. The shape of the GyrA subunit C-terminal domain (CTD) is not a sole determinant for controlling supercoiling efficiency. J Biol Chem 287:18645-54|
|Tretter, Elsa M; Berger, James M (2012) Mechanisms for defining supercoiling set point of DNA gyrase orthologs: I. A nonconserved acidic C-terminal tail modulates Escherichia coli gyrase activity. J Biol Chem 287:18636-44|
|Basu, Aakash; Schoeffler, Allyn J; Berger, James M et al. (2012) ATP binding controls distinct structural transitions of Escherichia coli DNA gyrase in complex with DNA. Nat Struct Mol Biol 19:538-46, S1|
|Vos, Seychelle M; Tretter, Elsa M; Schmidt, Bryan H et al. (2011) All tangled up: how cells direct, manage and exploit topoisomerase function. Nat Rev Mol Cell Biol 12:827-41|
|Bates, Andrew D; Berger, James M; Maxwell, Anthony (2011) The ancestral role of ATP hydrolysis in type II topoisomerases: prevention of DNA double-strand breaks. Nucleic Acids Res 39:6327-39|
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