InterPro : IPR003012

Name  Tetracycline transcriptional regulator, TetR Short Name  Tet_transcr_reg_TetR
Type  Family Description  The antibiotic tetracycline has a broad spectrum of activity, acting to inhibit bacterial protein synthesis by binding to the 30S ribosomal subunit, which prevents the association of the aminoacyl-tRNA to the ribosomal acceptor A site. Tetracycline binding is reversible, therefore diluting out the antibiotic can reverse its effects. Tetracycline resistance genes are often located on mobile elements, such as plasmids, transposons and/or conjugative transposons, which can sometimes be transferred between bacterial species. In certain cases, tetracycline can enhance the transfer of these elements, thereby promoting resistance amongst a bacterial colony. There are three types of tetracycline resistance: tetracycline efflux, ribosomal protection, and tetracycline modification [, ]: Tetracycline efflux proteins belong to the major facilitator superfamily. Efflux proteins are membrane-associated proteins that recognise and export tetracycline from the cell. They are found in both Gram-positive and Gram-negative bacteria []. There are at least 22 different tetracycline efflux proteins, grouped according to sequence similarity: Group 1 are Tet(A), Tet(B), Tet(C), Tet(D), Tet(E), Tet(G), Tet(H), Tet(J), Tet(Z) and Tet(30); Group 2 are Tet(K) and Tet(L); Group 3 are Otr(B) and Tcr(3); Group 4 is TetA(P); Group 5 is Tet(V). In addition, there are the efflux proteins Tet(31), Tet(33), Tet(V), Tet(Y), Tet(34), and Tet(35).Ribosomal protection proteins are cytoplasmic proteins that display homology with the elongation factors EF-Tu and EF-G. Protection proteins bind the ribosome, causing an alteration in ribosomal conformation that prevents tetracycline from binding. There are at least ten ribosomal protection proteins: Tet(M), Tet(O), Tet(S), Tet(W), Tet(32), Tet(36), Tet(Q), Tet(T), Otr(A), and TetB(P). Both Tet(M) and Tet(O) have ribosome-dependent GTPase activity, the hydrolysis of GTPproviding the energy for the ribosomal conformational changes. Tetracycline modification proteins include the enzymes Tet(37) and Tet(X), both of which inactivate tetracycline. In addition, there are the tetracycline resistance proteins Tet(U) and Otr(C).The expression of several of these tet genes is controlled by a family of tetracycline transcriptional regulators known as TetR. TetR family regulators are involved in the transcriptional control of multidrug efflux pumps, pathways for the biosynthesis of antibiotics, response to osmotic stress and toxic chemicals, control of catabolic pathways, differentiation processes, and pathogenicity []. The TetR proteins identified in over 115 genera of bacteria and archaea share a common helix-turn-helix (HTH) structure in their DNA-binding domain. However, TetR proteins can work in different ways: they can bind a target operator directly to exert their effect (e.g. TetR binds Tet(A) gene to repress it in the absence of tetracycline), or they can be involved in complex regulatory cascades in which the TetR protein can either be modulated by another regulator or TetR can trigger the cellular response. This entry represents the tetracycline transcriptional repressor TetR, which binds to the Tet(A) gene to repress its expression in the absence of tetracycline []. Tet(A) is a membrane-associated efflux protein that exports tetracycline from the cell before it can attach to ribosomes and inhibit polypeptide chain growth. TetR occurs as a homodimer and uses two helix-turn-helix (HTH) motifs to bind tandem DNA operators, thereby blocking the expression of the associated genes, TetA and TetR. The structure of the class D TetR repressor protein []involves 10 alpha-helices, with connecting turns and loops. The three N-terminal helices constitute the DNA-binding HTH domain, which has an inverse orientation compared with HTH motifsin other DNA-binding proteins. The core of the protein, formed by helices 5-10, is responsible for dimerisation and contains, for each monomer, a binding pocket that accommodates tetracycline in the presence of a divalent cation.

Sequence Features

GO Displayer


InterPro protein domain ID --> Contigs



0 Child Features

3 Contains

Id Name Short Name Type
IPR015893 Tetracycline transcriptional regulator, TetR-like, C-terminal Tet_transcr_reg_TetR-like_C Domain
IPR001647 DNA-binding HTH domain, TetR-type HTH_TetR Domain
IPR004111 Tetracycline transcriptional regulator, TetR, C-terminal Tet_transcr_reg_TetR_C Domain

0 Found In

0 Parent Features

6 Publications

First Author Title Year Journal Volume Pages
Roberts MC Acquired tetracycline and/or macrolide-lincosamides-streptogramin resistance in anaerobes. 2003 Anaerobe 9 63-9
Roberts MC Update on acquired tetracycline resistance genes. 2005 FEMS Microbiol Lett 245 195-203
Speer BS Bacterial resistance to tetracycline: mechanisms, transfer, and clinical significance. 1992 Clin Microbiol Rev 5 387-99
Ramos JL The TetR family of transcriptional repressors. 2005 Microbiol Mol Biol Rev 69 326-56
Kisker C The complex formed between Tet repressor and tetracycline-Mg2+ reveals mechanism of antibiotic resistance. 1995 J Mol Biol 247 260-80
Hinrichs W Structure of the Tet repressor-tetracycline complex and regulation of antibiotic resistance. 1994 Science 264 418-20

To cite PlanMine, please refer to the following publication:

Rozanski, A., Moon, H., Brandl, H., Martín-Durán, J. M., Grohme, M., Hüttner, K., Bartscherer, K., Henry, I., & Rink, J. C.
PlanMine 3.0—improvements to a mineable resource of flatworm biology and biodiversity
Nucleic Acids Research, gky1070. doi:10.1093/nar/gky1070 (2018)