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Disrupting the Non-specific Interactions between DNA and the Escherichia coli Transcriptional Repressor NikR

The Escherichia coli transcription factor NikR is responsible for nickel-mediated repression of the nik operon. The crystal structure of NikR in complex with its operator sequence provided insight into the mechanistic details of nickel-activated NikR-DNA complex formation. The crystal structure revealed that the α3 helix and its preceding loop (residues 63-79) in two of the metal-binding domains—which become structurally ordered after high-affinity nickel binding—make non-specific contacts with the DNA phosphodiester backbone. The proposed mechanism of NikR binding to DNA suggests that the non-specific interactions between the DNA phosphodiester backbone and the positively-charged residues Lys64 and Arg65 anchor NikR to the DNA, thereby allowing the protein to initiate a one-dimensional search for its recognition sequence. The DNA-binding studies presented here strongly support an important role for Lys64 and Arg65 in NikR-DNA complex formation which is in agreement with the proposed model of NikR binding to DNA.

Identiferoai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:OTU.1807/32475
Date20 July 2012
CreatorsKrecisz, Sandra
ContributorsZamble, Deborah
Source SetsLibrary and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada
Languageen_ca
Detected LanguageEnglish
TypeThesis

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