Stabilization of lambda repressor against thermal denaturation by site-directed Gly----Ala changes in alpha-helix 3.
Oligonucleotide-directed mutagenesis has been used to replace alpha-helical glycines in the N-terminal domain of lambda repressor with alanines. Since alanine is a significantly better helix-forming residue than glycine, these changes were predicted to have a stabilizing effect. We show that the Gly46----Ala substitution, the Gly48----Ala substitution, and the double substitution increase the melting temperature of the N-terminal domain by 3-6 degrees.
Hecht
M H
MH
Department of Biology, Massachusetts Institute of Technology, Cambridge 02139.
Sturtevant
J M
JM
Sauer
R T
RT
D000595:Amino Acid Sequence; D004268:DNA-Binding Proteins; D005809:Genes, Regulator; D006358:Hot Temperature; D008969:Molecular Sequence Data; D009154:Mutation; D011487:Protein Conformation; D011489:Protein Denaturation; D012097:Repressor Proteins / Q000235:genetics; D014157:Transcription Factors / Q000235:genetics; D014764:Viral Proteins; D054334:Viral Regulatory and Accessory Proteins
D004268:DNA-Binding Proteins; D012097:Repressor Proteins; D014157:Transcription Factors; D014764:Viral Proteins; D054334:Viral Regulatory and Accessory Proteins; C016649:phage repressor proteins