This domain is found at the C-terminal end of Transcriptional regulator, TetR family from Thermotoga maritima (TM_1030) and similar sequences from bacteria. TM_1030 shows high similarity to members of the TetR family at the N-terminal DNA-binding domain (Pfam:PF00440). However, differences are much greater in the C-terminal regulatory domain, which shows an all-helical structure [1,2].

1: Crystal structure of a transcriptional regulator TM1030 from Thermotoga maritima solved by an unusual MAD experiment. Koclega KD, Chruszcz M, Zimmerman MD, Cymborowski M, Evdokimova E, Minor W; J Struct Biol. 2007;159:424-432. PMID:17588774

2: Crystal structure of TM1030 from Thermotoga maritima at 2.3 A resolution reveals molecular details of its transcription repressor function. Premkumar L, Rife CL, Sri Krishna S, McMullan D, Miller MD, Abdubek P, Ambing E, Astakhova T, Axelrod HL, Canaves JM, Carlton D, Chiu HJ, Clayton T, DiDonato M, Duan L, Elsliger MA, Feuerhelm J, Floyd R, Grzechnik SK, Hale J, Hampton E, Han GW, Haugen J, Jaroszewski L, Jin KK, Klock HE, Knuth MW, Koesema E, Kovarik JS, Kreusch A, Levin I, McPhillips TM, Morse AT, Nigoghossian E, Okach L, Oommachen S, Paulsen J, Quijano K, Reyes R, Rezezadeh F, Rodionov D, Schwarzenbacher R, Spraggon G, van den Bedem H, White A, Wolf G, Xu Q, Hodgson KO, Wooley J, Deacon AM, Godzik A, Lesley SA, Wilson IA; Proteins. 2007;68:418-424. PMID:17444523