Crystal structure of a bacterial topoisomerase IB in complex with DNA reveals a secondary DNA binding site Journal Article

   

Authors:	Patel, A.; Yakovleva, L.; Shuman, S.; Mondragón, A.
Article Title:	Crystal structure of a bacterial topoisomerase IB in complex with DNA reveals a secondary DNA binding site
Abstract:	Type IB DNA topoisomerases (TopIB) are monomeric enzymes that relax supercoils by cleaving and resealing one strand of duplex DNA within a protein clamp that embraces a ∼21 DNA segment. A longstanding conundrum concerns the capacity of TopIB enzymes to stabilize intramolecular duplex DNA crossovers and form protein-DNA synaptic filaments. Here we report a structure of Deinococcus radiodurans TopIB in complex with a 12 bp duplex DNA that demonstrates a secondary DNA binding site located on the surface of the C-terminal domain. It comprises a distinctive interface with one strand of the DNA duplex and is conserved in all TopIB enzymes. Modeling of a TopIB with both DNA sites suggests that the secondary site could account for DNA crossover binding, nucleation of DNA synapsis, and generation of a filamentous plectoneme. Mutations of the secondary site eliminate synaptic plectoneme formation without affecting DNA cleavage or supercoil relaxation. © 2010 Elsevier Ltd.
Keywords:	controlled study; unclassified drug; mutation; nonhuman; carboxy terminal sequence; bacteria (microorganisms); dna; double stranded dna; binding site; crystal structure; hydrogen bond; binding sites; synapsis; dna, bacterial; dna cleavage; dna topoisomerase; crossing over; poxvirus; dna supercoiling; bacteria; dna topoisomerase 1b; deinococcus radiodurans; dna protein complex; biophysical processes; deinococcus; isomerases
Journal Title:	Structure
Volume:	18
Issue:	6
ISSN:	0969-2126
Publisher:	Cell Press
Date Published:	2010-06-09
Start Page:	725
End Page:	733
Language:	English
DOI:	10.1016/j.str.2010.03.007
PUBMED:	20541510
PROVIDER:	scopus
PMCID:	PMC2886027
DOI/URL:	http://www.scopus.com/inward/record.url?eid=2-s2.0-77953583981&partnerID=40&md5=e06cc648ad6f31b54a2f1e42f5dabd42
Notes:	--- - "Cited By (since 1996): 2" - "Export Date: 20 April 2011" - "CODEN: STRUE" - "Source: Scopus"

https://synapse.mskcc.org/synapse/works/has_related_data_chk/4823