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Escherichia coli β-clamp slows down DNA polymerase I dependent nick translation while accelerating ligation.

DIR@IMTECH: CSIR-Institute of Microbial Technology

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Title Escherichia coli β-clamp slows down DNA polymerase I dependent nick translation while accelerating ligation.
 
Creator Bhardwaj, Amit
Ghose, Debarghya
Thakur, Krishan Gopal
Dutta, Dipak
 
Subject QR Microbiology
 
Description The nick translation property of DNA polymerase I (Pol I) ensures the maturation of Okazaki fragments by removing primer RNAs and facilitating ligation. However, prolonged nick translation traversing downstream DNA is an energy wasting futile process, as Pol I simultaneously polymerizes and depolymerizes at the nick sites utilizing energy-rich dNTPs. Using an in vitro assay system, we demonstrate that the β-clamp of the Escherichia coli replisome strongly inhibits nick translation on the DNA substrate. To do so, β-clamp inhibits the strand displacement activity of Pol I by interfering with the interaction between the finger subdomain of Pol I and the downstream primer-template junction. Conversely, β-clamp stimulates the 5' exonuclease property of Pol I to cleave single nucleotides or shorter oligonucleotide flaps. This single nucleotide flap removal at high frequency increases the probability of ligation between the upstream and downstream DNA strands at an early phase, terminating nick translation. Besides β-clamp-mediated ligation helps DNA ligase to seal the nick promptly during the maturation of Okazaki fragments.
 
Publisher Public Library of Science
 
Date 2018-06-20
 
Type Article
PeerReviewed
 
Relation http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0199559
http://crdd.osdd.net/open/2093/
 
Identifier Bhardwaj, Amit and Ghose, Debarghya and Thakur, Krishan Gopal and Dutta, Dipak (2018) Escherichia coli β-clamp slows down DNA polymerase I dependent nick translation while accelerating ligation. PloS one, 13 (6). e0199559. ISSN 1932-6203