TY  - JOUR
AU  - Palm, Gottfried Julius
AU  - Buchholz, Ina
AU  - Werten, Sebastiaan
AU  - Girbardt, Britta
AU  - Berndt, Leona
AU  - Delcea, Mihaela
AU  - Hinrichs, Winfried
TI  - Thermodynamics, cooperativity and stability of the tetracycline repressor (TetR) upon tetracycline binding
JO  - Biochimica et biophysica acta / Proteins and proteomics
VL  - 1868
IS  - 6
SN  - 1570-9639
CY  - Amsterdam [u.a.]
M1  - PUBDB-2020-03359
SP  - 140404
PY  - 2020
AB  - Allosteric regulation of the Tet repressor (TetR) homodimer relies on tetracycline binding that abolishes the affinity for the DNA operator. Previously, interpretation of circular dichroism data called for unfolding of the α-helical DNA-binding domains in absence of binding to DNA or tetracycline. Our small angle X-ray scattering of TetR(D) in solution contradicts this unfolding as a physiological process. Instead, in the core domain crystal structures analyses show increased immobilisation of helix α9 and two C-terminal turns of helix α8 upon tetracycline binding. Tetracycline complexes of TetR(D) and four single-site alanine variants were characterised by isothermal titration calorimetry, fluorescence titration, X-ray crystal structures, and melting curves. Five crystal structures confirm that Thr103 is a key residue for the allosteric events of induction, with the T103A variant lacking induction by any tetracycline. The T103A variant shows anti-cooperative inducer binding, and a melting curve of the tetracycline complex different to TetR(D) and other variants. For the N82A variant inducer binding is clearly anti-cooperative but triggers the induced conformation.
LB  - PUB:(DE-HGF)16
C6  - pmid:32114262
UR  - <Go to ISI:>//WOS:000527000700004
DO  - DOI:10.1016/j.bbapap.2020.140404
UR  - https://bib-pubdb1.desy.de/record/448261
ER  -