2XGD

Crystal structure of a designed homodimeric variant T-A(L)A(L) of the tetracycline repressor

Summary for 2XGD

• Entry DOI: 10.2210/pdb2xgd/pdb
• Related: 1A6I 1BJ0 1BJY 1BJZ 1DU7 1ORK 1QPI 2TCT 2TRT 2VKE 2VKV 2X6O 2X9D 2XB5 2XGC 2XGE
• Descriptor: TETRACYCLINE REPRESSOR PROTEIN CLASS B FROM TRANSPOSON TN10, TETRACYCLINE REPRESSOR PROTEIN CLASS D, CHLORIDE ION (3 entities in total)
• Functional Keywords: chimera, transcription, transcription regulation, antibiotic resistance
• Biological source: ESCHERICHIA COLI
• Total number of polymer chains: 1
• Total formula weight: 23522.18

Authors

Stiebritz, M.T.,Wengrzik, S.,Richter, J.P.,Muller, Y.A. (deposition date: 2010-06-03, release date: 2010-09-22, Last modification date: 2023-12-20)

Primary citation

Stiebritz, M.T.,Wengrzik, S.,Klein, D.L.,Richter, J.P.,Srebrzynski, A.,Weiler, S.,Muller, Y.A.
Computational Design of a Chain-Specific Tetracycline Repressor Heterodimer.
J.Mol.Biol., 403:371-, 2010

PubMed Abstract: The specificity and selectivity of protein-protein interactions are of central importance for many biological processes, including signal transduction and transcription control. We used the in-house side-chain packing program MUMBO to computationally design a chain-specific heterodimeric variant of the bacterial transcription regulator tetracycline repressor (TetR), called T-A(A)B. Our goal was to engineer two different TetR chain variants, A and B, that no longer interact as AA or BB homodimers but selectively recombine to form heterodimers. Although 56 residues from each chain contribute to a dimer interface as large as 2200 Å(2) in wild-type TetR, the substitution of only three residues in one chain and two residues in a second chain sufficed for generating specificity in a T-A(A)B heterodimer variant. The design was corroborated in vivo by a cell-based transcription assay, and in vitro by CD spectroscopy and X-ray crystallography. Crystal structure analyses showed that while selectivity in the B chain is achieved entirely through van der Waals repulsion, the best selectivity in the A chain is obtained for the variant with the lowest number of atoms in the interface, thus possibly leading to underpacking of the dimer interface. This results in a marked decrease in thermal stability and a drastic reduction in the solubility of the T-A(A)A(A) homodimer in comparison to the designed T-A(A)B heterodimer variant.

PubMed: 20816982
DOI: 10.1016/J.JMB.2010.07.055

Experimental method

X-RAY DIFFRACTION (2.25 Å)