>TIGR02405 trehalos_R_Ecol trehalose operon repressor; InterPro: IPR012771 Trehalose is a non-reducing disaccharide which can be used as both a carbon source and an osmoprotectant in bacteria. Trehalose uptake into the cytoplasm occurs via a trehalose-specific phosphotransferase system which phosphorylates trehalase to trehalose-6-phosphate (Tre6P) during transport into the cytoplasm, and a hydrolase which hydrolyses Tre6P to glucose and glucose-6-phophate. This entry represents LacI-type TreR, a transcriptional repressor of trehalose uptake found mainly within the gamma-proteobacteria. It does not include the GntR-type TreR's such as those found in Bacillus species. It is capable of binding both the inducer Tre6P and trehalose. Binding of trehalose does not affect the repressor's affinity for its DNA binding site, while binding Tre6P substantially reduces its affinity. The repression activity of TreR is therefore regulated by the ratio of trehalose to Tre6P within the cell . The protein is composed of two domains, an N-terminal DNA-binding helix-turn-helix domain, and a C-terminal effector-binding domain which is homologous to that of LacI. The effector-binding domain is composed of two subdomains, both of which form an alpha-beta-alpha sandwhich, with the effector binding site located at the interface of these subdomains . Tre6P and trehalose bind competitively to this site, with the affinty for trehalose substantially lower than that for Tre6P.; GO: 0003677 DNA binding, 0016566 specific transcriptional repressor activity, 0005991 trehalose metabolic process, 0016481 negative regulation of transcription.

Probab=90.06  E-value=0.11  Score=30.72  Aligned_cols=41  Identities=24%  Similarity=0.338  Sum_probs=33.4

Q ss_pred             CCCHHHHHHHHHHHHHHHHHHHCCCCCCCHHHHHHHHHHHC
Q ss_conf             99499999986342999988755899944899999999928
Q gi|254781147|r   34 KLTQKEIRNRTGFAQSWISELETGKSTINIDNMIILAHTLD   74 (83)
Q Consensus        34 gltq~ela~~~gis~~~is~iE~G~~~~~~~~l~~la~al~   74 (83)
T Consensus         1 kLTIkDIArLagVgKSTVSRVLnNe~~V~~~tRERVE~viq   41 (311)
T TIGR02405         1 KLTIKDIARLAGVGKSTVSRVLNNESKVSIETRERVEAVIQ   41 (311)
T ss_pred             CCHHHHHHHHHCCCCEEEEEEEECCCCCCCHHHHHHHHHHH
T ss_conf             96177769770886202331561688887203368888875