title: Mutations in lambda repressor's amino-terminal domain: implications for protein stability and DNA binding.
abstract: The DNA binding properties of 52 different single-amino acid substitutions in lambda repressor's amino-terminal domain have been characterized. Seven proteins bearing mutations that change solvent-exposed side chains have been purified. The amino-terminal domains of these mutant repressors are folded and are comparable to the wild-type amino-terminal domain in thermal stability. In contrast, a purified mutant repressor bearing a substitution in a buried side chain contains an amino-terminal domain with decreased thermal stability. We argue that mutations that alter solvent-exposed wild-type side chains define residues that form the operator DNA binding surface of lambda repressor whereas completely or partially buried mutations exert their effect by decreasing protein stability.
mesh_terms: D000595:Amino Acid Sequence; D010582:Bacteriophage lambda / Q000235:genetics*; D001483:Base Sequence; D004279:DNA, Viral / Q000378:metabolism*; D004268:DNA-Binding Proteins; D008958:Models, Molecular; D009154:Mutation; D011487:Protein Conformation; D012097:Repressor Proteins / Q000235:genetics*; D013329:Structure-Activity Relationship; D013820:Thermolysin / Q000378:metabolism; D014157:Transcription Factors / Q000235:genetics*; D014764:Viral Proteins; D054334:Viral Regulatory and Accessory Proteins
chemical_list: D004279:DNA, Viral; D004268:DNA-Binding Proteins; D012097:Repressor Proteins; D014157:Transcription Factors; D014764:Viral Proteins; D054334:Viral Regulatory and Accessory Proteins; C016649:phage repressor proteins; D013820:Thermolysin