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Modulation of DNA‐binding specificity within the nuclear receptor family by substitutions at a single amino acid position
Author(s) -
Zilliacus Johanna,
Wright Anthony P. H.,
CarlstedtDuke Jan,
Nilsson Lennart,
Gustafsson JanÅke
Publication year - 1995
Publication title -
proteins: structure, function, and bioinformatics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.699
H-Index - 191
eISSN - 1097-0134
pISSN - 0887-3585
DOI - 10.1002/prot.340210107
Subject(s) - biology , dna , transcription factor , dna binding domain , mutant , nuclear receptor , genetics , protein–dna interaction , amino acid , gene , binding site , dna binding site , transcription (linguistics) , hmg box , base pair , biochemistry , dna binding protein , gene expression , promoter , linguistics , philosophy
Regulation of gene expression involves a large number of transcription factors with unique DNA‐binding properties. Many transcription factors belong to families of related proteins that bind to similar but distinct sequences. In this study we have analyzed how amino acid substitutions at a single position in the DNA‐binding domain modulate the DNA binding specificity within the nuclear receptor family of transcription factors. All possible amino acids were introduced at the first position in the DNA recognition helix, and the specificities of the mutants were analyzed using response elements containing all combinations of bases at two variable base pair positions. All mutant proteins were functional in DNA binding, and could be divided into classes of mutants with different response element specificities. By combining functional data with analysis of the structural effects of the mutations by molecular modeling, we could identify both prohibitive steric interactions as well as positive interactions, such as hydrogen bonds, that function as important determinants for specificity. Only the residues found naturally in the glucocorticoid and estrogen receptors, glycine and glutamate, produce unique binding specificities. The specificities of the other mutants overlap with each other somewhat but the substitutions clearly have potential to contribute to diversity within the nuclear receptor family. © 1995 Wiley‐Liss, Inc.