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Single amino acid substitutions alter helix‐loop‐helix protein specificity for bases flanking the core CANNTG motif.
Author(s) -
Fisher F.,
Goding C.R.
Publication year - 1992
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.1002/j.1460-2075.1992.tb05503.x
Subject(s) - biology , genetics , motif (music) , basic helix loop helix , flanking maneuver , helix (gastropod) , amino acid , dna binding protein , gene , transcription factor , ecology , snail , history , physics , archaeology , acoustics
While all basic region/helix‐loop‐helix (bHLH) proteins bind the consensus CANNTG motif, other factors must be involved in determining regulatory specificity. In this report we show that bases outside this core 6 bp are involved in determining the specificity of binding. Thus, binding of the yeast bHLH protein PHO4, but not CPF‐1, is inhibited by the presence of a T residue immediately 5′ to their common CACGTG recognition sequence. PHO4 binding specificity is altered by mutation at any of three different positions in the basic region, including a single Glu to Asp substitution. The significance of these data for DNA‐binding and transcription regulation by the bHLH family of transcription factors is discussed.