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PubMed · 10391902

Specific DNA recognition by F Factor TraY involves beta-sheet residues.

P L Lum·J F Schildbach
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Abstract

The F Factor TraY protein is a sequence-specific DNA-binding protein required for efficient conjugal transfer. Genetic and biochemical studies indicate that TraY has two functional roles in conjugation. TraY binds to the PY promoter to up-regulate transcription of tra genes. TraY also binds to the plasmid origin of transfer (oriT), serving as an accessory protein in the nicking of F Factor in preparation for transfer. TraY is thought to belong to the ribbon-helix-helix family of transcription factors. These proteins contact DNA using residues of an antiparallel beta-sheet. We engineered and characterized six TraY mutants each having a single potential beta-sheet DNA contact residue replaced with Ala. Most TraY mutants had significantly reduced affinity for the TraY oriT binding site while possessing near wild-type stability and nonspecific DNA recognition. These results indicate that TraY beta-sheet residues participate in DNA recognition, and support inclusion of TraY in the ribbon-helix-helix family.

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Amino Acid SequenceBinding SitesBinding, CompetitiveCloning, MolecularConjugation, GeneticDNA-Binding ProteinsEscherichia coliEscherichia coli ProteinsF FactorGene Expression Regulation, BacterialModels, MolecularMolecular Sequence DataMutagenesis, Site-DirectedMutationProtein DenaturationProtein EngineeringProtein FoldingProtein Structure, SecondaryJournal ArticleResearch Support, U.S. Gov't, Non-P.H.S.

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P L Lum, J F Schildbach. 1999-07-09. Specific DNA recognition by F Factor TraY involves beta-sheet residues.. https://doi.org/10.1074/jbc.274.28.19644

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