PMID- 16844141
OWN - NLM
STAT- MEDLINE
DCOM- 20060928
LR  - 20061115
IS  - 0022-2836 (Print)
IS  - 0022-2836 (Linking)
VI  - 361
IP  - 2
DP  - 2006 Aug 11
TI  - Two-way interdomain signal transduction in tetracycline repressor.
PG  - 382-9
AB  - The transcription of genes encoding resistance to the antibiotic, tetracycline 
      (Tc), is repressed by tetracycline repressor (TetR), which is a homodimeric 
      alpha-helical protein possessing a small N-terminal DNA binding domain (DNB 
      domain) and a larger C-terminal domain (TBD domain). Binding of Tc to the TBD 
      domain induces a subtle conformational change in the DNB domain that leads to 
      abrogation of its DNA-binding activity, and induction of Tc resistance. While 
      most previous studies on TetR have focused on the effects of Tc-binding on the 
      DNB domain conformation, here we have investigated the role of the DNB domain in 
      modulating Tc binding. We have discovered that a TBD domain construct entirely 
      lacking the DNB domain displays a drastic reduction in Tc-binding affinity even 
      though the DNB domain is far from the Tc-binding site. In the context of 
      full-length TetR, highly destabilizing amino acid substitutions in the DNB domain 
      cause reductions in Tc-binding activity. Strikingly, the DNB domains of these 
      mutants, which are completely unfolded in the absence of Tc, are induced to fold 
      when Tc is bound. These results demonstrate that there is a previously 
      unrecognized two-way interdomain signaling mechanism in TetR whereby the DNB 
      domain is required for maximal Tc-binding by the TBD domain, and Tc-binding in 
      the TBD domain leads to stabilization of the DNB domain. Furthermore, our work 
      suggests that detailed thermodynamic and kinetic studies on mutant forms of other 
      allosteric proteins may also reveal surprising and previously undetected modes of 
      interdomain communication.
FAU - Reichheld, Sean E
AU  - Reichheld SE
AD  - Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada M5S 
      1A8.
FAU - Davidson, Alan R
AU  - Davidson AR
LA  - eng
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
DEP - 20060630
PL  - Netherlands
TA  - J Mol Biol
JT  - Journal of molecular biology
JID - 2985088R
RN  - 0 (Repressor Proteins)
RN  - 0 (Tetracyclines)
RN  - 0 (tetracycline resistance-encoding transposon repressor protein)
SB  - IM
MH  - Amino Acid Substitution
MH  - *Gene Expression Regulation, Bacterial
MH  - Kinetics
MH  - Models, Molecular
MH  - Protein Conformation
MH  - Protein Folding
MH  - Protein Structure, Tertiary
MH  - Repressor Proteins/*chemistry/genetics/metabolism
MH  - Signal Transduction
MH  - Tetracycline Resistance/*physiology
MH  - Tetracyclines/*pharmacology
MH  - Thermodynamics
EDAT- 2006/07/18 09:00
MHDA- 2006/09/29 09:00
CRDT- 2006/07/18 09:00
PHST- 2006/05/02 00:00 [received]
PHST- 2006/06/14 00:00 [accepted]
PHST- 2006/07/18 09:00 [pubmed]
PHST- 2006/09/29 09:00 [medline]
PHST- 2006/07/18 09:00 [entrez]
AID - S0022-2836(06)00756-X [pii]
AID - 10.1016/j.jmb.2006.06.035 [doi]
PST - ppublish
SO  - J Mol Biol. 2006 Aug 11;361(2):382-9. doi: 10.1016/j.jmb.2006.06.035. Epub 2006 
      Jun 30.