Identification of proximal sites for unwound DNA substrate in Escherichia coli topoisomerase I with oxidative crosslinking
Date of this Version
1-1-2017
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
27926785
Recommended Citation
Cheng, Bokun; Zhou, Qingxuan; Weng, Liwei; Leszyk, John D.; Greenberg, Marc M.; and Tse-Dinh, Yuk-Ching, "Identification of proximal sites for unwound DNA substrate in Escherichia coli topoisomerase I with oxidative crosslinking" (2017). Biomolecular Sciences Institute: Faculty Publications. 63.
https://digitalcommons.fiu.edu/biomolecular_fac/63
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