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dc.contributor.authorXu, Joseph S.
Hewitt, Madeleine N.
Gulati, Jaskeerat S.
Cruz, Matthew A.
Zhan, Hongli
Liu, Shirley
Matthews, Kathleen S.
dc.date.accessioned 2018-07-11T20:57:33Z
dc.date.available 2018-07-11T20:57:33Z
dc.date.issued 2018
dc.identifier.citation Xu, Joseph S., Hewitt, Madeleine N., Gulati, Jaskeerat S., et al.. "Lactose repressor hinge domain independently binds DNA." Protein Science, 27, no. 4 (2018) Wiley: 839-847. https://doi.org/10.1002/pro.3372.
dc.identifier.urihttps://hdl.handle.net/1911/102407
dc.description.abstract The short 8–10 amino acid “hinge” sequence in lactose repressor (LacI), present in other LacI/GalR family members, links DNA and inducer‐binding domains. Structural studies of full‐length or truncated LacI‐operator DNA complexes demonstrate insertion of the dimeric helical “hinge” structure at the center of the operator sequence. This association bends the DNA ∼40° and aligns flanking semi-symmetric DNA sites for optimal contact by the N-terminal helix-turn-helix (HtH) sequences within each dimer. In contrast, the hinge region remains unfolded when bound to nonspecific DNA sequences. To determine ability of the hinge helix alone to mediate DNA binding, we examined (i) binding of LacI variants with deletion of residues 1–50 to remove the HtH DNA binding domain or residues 1–58 to remove both HtH and hinge domains and (ii) binding of a synthetic peptide corresponding to the hinge sequence with a Val52Cys substitution that allows reversible dimer formation via a disulfide linkage. Binding affinity for DNA is orders of magnitude lower in the absence of the helix‐turn‐helix domain with its highly positive charge. LacI missing residues 1–50 binds to DNA with ∼4-fold greater affinity for operator than for nonspecific sequences with minimal impact of inducer presence; in contrast, LacI missing residues 1–58 exhibits no detectable affinity for DNA. In oxidized form, the dimeric hinge peptide alone binds to O1 and nonspecific DNA with similarly small difference in affinity; reduction to monomer diminished binding to both O1 and nonspecific targets. These results comport with recent reports regarding LacI hinge interaction with DNA sequences.
dc.language.iso eng
dc.publisher Wiley
dc.rights This is an open access article under the terms of the Creative Commons Attribution-NonCommercial License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited and is not used for commercial purposes.
dc.rights.urihttps://creativecommons.org/licenses/by-nc/4.0/
dc.title Lactose repressor hinge domain independently binds DNA
dc.type Journal article
dc.citation.journalTitle Protein Science
dc.subject.keywordallosteric regulation
DNA binding protein
DNA operator
DNA–protein interaction
hinge helix
lactose repressor protein
structure–function
dc.citation.volumeNumber 27
dc.citation.issueNumber 4
dc.type.dcmi Text
dc.identifier.doihttps://doi.org/10.1002/pro.3372
dc.identifier.pmcid PMC5866929
dc.identifier.pmid 29318690
dc.type.publication publisher version
dc.citation.firstpage 839
dc.citation.lastpage 847


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