Identification of proximal sites for unwound DNA substrate in Escherichia coli topoisomerase I with oxidative crosslinking.

Authors

Bokun Cheng, New York Medical College
Qingxuan Zhou, Biomolecular Sciences Institute and Department of Chemistry and Biochemistry, Florida International UniversityFollow
Liwei Weng, Johns Hopkins University
John D. Leszyk, University of Massachusetts Medical School
Marc M. Greenberg, Johns Hopkins University
Yuk-Ching Tse-Dinh, Biomolecular Sciences Institute and Department of Chemistry and Biochemistry, Florida International UniversityFollow

Date of this Version

11-22-2016

Document Type

Article

Rights

default

Abstract

Topoisomerases catalyze changes in DNA topology by directing the movement of DNA strands through consecutive cleavage-rejoining reactions of the DNA backbone. We describe the use of a phenylselenyl-modified thymidine incorporated into a specific position of a partially unwound DNA substrate in crosslinking studies of Escherichia coli topoisomerase I to gain new insights into its catalytic mechanism. Crosslinking of the phenylselenyl-modified thymidine to the topoisomerase protein was achieved by the addition of a mild oxidant. Following nuclease and trypsin digestion, lysine residues on topoisomerase I crosslinked to the modified thymidine were identified by mass spectrometry. The crosslinked sites may correspond to proximal sites for the unwound DNA strand as it interacts with enzyme in the different stages of the catalytic cycle.

DOI

10.1002/1873-3468.12517

Identifier

FIDC001631

Comments

Post Print Version.

The published version is available at http://dx.doi.org/10.1002/1873-3468.12517

Recommended Citation

Cheng, B., Zhou, Q., Weng, L., Leszyk, J. D., Greenberg, M. M. and Tse-Dinh, Y.-C. (2017), Identification of proximal sites for unwound DNA substrate in Escherichia coli topoisomerase I with oxidative crosslinking. FEBS Lett, 591: 28–38. doi:10.1002/1873-3468.12517