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Tet repressor mutants with altered effector binding and allostery
Author(s) -
Henßler EvaMaria,
Bertram Ralph,
Wisshak Stefanie,
Hillen Wolfgang
Publication year - 2005
Publication title -
the febs journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.981
H-Index - 204
eISSN - 1742-4658
pISSN - 1742-464X
DOI - 10.1111/j.1742-4658.2005.04868.x
Subject(s) - tetr , effector , allosteric regulation , cooperativity , repressor , dna , mutant , biophysics , ligand (biochemistry) , binding site , plasma protein binding , cooperative binding , chemistry , mutation , genetics , biology , microbiology and biotechnology , transcription factor , receptor , gene
To learn about the correlation between allostery and ligand binding of the Tet repressor (TetR) we analyzed the effect of mutations in the DNA reading head–core interface on the effector specific TetR i2 variant. The same mutations in these subdomains can lead to completely different activities, e.g. the V99G exchange in the wild‐type leads to corepression by 4‐ddma‐atc without altering DNA binding. However, in TetR i2 it leads to 4‐ddma‐atc dependent repression in combination with reduced DNA binding in the absence of effector. The thermodynamic analysis of effector binding revealed decreased affinities and positive cooperativity. Thus, mutations in this interface can influence DNA binding as well as effector binding, albeit both ligand binding sites are not in direct contact to these altered residues. This finding represents a novel communication mode of TetR. Thus, allostery may not only operate by the structural change proposed on the basis of the crystal structures.