title: The DNA-binding properties of an artificial 42-residue polypeptide derived from a natural repressor.
abstract: Bacteriophage 434 repressor recognizes the operator sequences ACAAG and ACAAT. As the same or similar sequences occur in the enhancer region of HIV-1, 434 repressor was a potential HIV enhancer-binding protein. We found that the interaction of the DNA-binding domain of 434 repressor with a 57-bp HIV enhancer DNA was very weak whereas a 42-residue construct, comprising the recognition helix and four copies of a positively charged segment of the repressor, bound strongly. The results of footprint and cell-free in vitro transcription studies showed that the 42-residue peptide bound preferably to the enhancer region of HIV-1 and acted as an artificial repressor. Replacement of an essential glutamine of the recognition helix by glutamic acid resulted in a partial shift of the sequence specificity of the 42-residue peptide.
authors.affiliation: Biochemisches Institut, Universität Zürich, Switzerland.
authors.forename: T
authors.initials: T
authors.lastname: Hehlgans
authors.forename: M
authors.initials: M
authors.lastname: Stolz
authors.forename: S
authors.initials: S
authors.lastname: Klauser
authors.forename: T
authors.initials: T
authors.lastname: Cui
authors.forename: P
authors.initials: P
authors.lastname: Salgam
authors.forename: S B
authors.initials: SB
authors.lastname: Verca
authors.forename: M
authors.initials: M
authors.lastname: Widmann
authors.forename: A
authors.initials: A
authors.lastname: Leiser
authors.forename: K
authors.initials: K
authors.lastname: Städler
authors.forename: B
authors.initials: B
authors.lastname: Gutte
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D001665:Binding Sites; D004279:DNA, Viral / Q000235:genetics / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000737:chemistry*; D004742:Enhancer Elements, Genetic; D015967:Gene Expression Regulation, Viral; D016325:HIV Long Terminal Repeat; D015497:HIV-1 / Q000235:genetics*; D008969:Molecular Sequence Data; D009875:Operator Regions, Genetic; D010455:Peptides / Q000378:metabolism*; D012097:Repressor Proteins / Q000737:chemistry*; D013329:Structure-Activity Relationship; D014157:Transcription Factors; D014764:Viral Proteins / Q000737:chemistry*
chemical_list: C063367:434-repressor protein, Bacteriophage 434; D004279:DNA, Viral; D004268:DNA-Binding Proteins; D010455:Peptides; D012097:Repressor Proteins; D014157:Transcription Factors; D014764:Viral Proteins