>TIGR02984 Sig-70_plancto1 RNA polymerase sigma-70 factor, Planctomycetaceae-specific subfamily 1; InterPro: IPR014326 The bacterial core RNA polymerase complex, which consists of five subunits, is sufficient for transcription elongation and termination but is unable to initiate transcription. Transcription initiation from promoter elements requires a sixth, dissociable subunit called a sigma factor, which reversibly associates with the core RNA polymerase complex to form a holoenzyme . RNA polymerase recruits alternative sigma factors as a means of switching on specific regulons. Most bacteria express a multiplicity of sigma factors. Two of these factors, sigma-70 (gene rpoD), generally known as the major or primary sigma factor, and sigma-54 (gene rpoN or ntrA) direct the transcription of a wide variety of genes. The other sigma factors, known as alternative sigma factors, are required for the transcription of specific subsets of genes. With regard to sequence similarity, sigma factors can be grouped into two classes, the sigma-54 and sigma-70 families. Sequence alignments of the sigma70 family members reveal four conserved regions that can be further divided into subregions eg. sub-region 2.2, which may be involved in the binding of the sigma factor to the core RNA polymerase; and sub-region 4.2, which seems to harbor a DNA-binding 'helix-turn-helix' motif involved in binding the conserved -35 region of promoters recognized by the major sigma factors , . This group of sigma factors are members of the sigma-70 family (IPR014284 from INTERPRO) and are apparently found only in the Planctomycetaceae family including the genus s Gemmata and Pirellula, in which seven sequences are found.; GO: 0003677 DNA binding, 0003700 transcription factor activity, 0016987 sigma factor activity, 0006352 transcription initiation, 0006355 regulation of transcription DNA-dependent.

Probab=95.38  E-value=0.042  Score=32.37  Aligned_cols=46  Identities=17%  Similarity=0.112  Sum_probs=39.0

Q ss_pred             CCCCHHHHHHHHH-HHCCCCHHHHHHHHCCCHHHHHHHHHHHHHHHC
Q ss_conf             8889779999999-985999799999949998899999999999807
Q gi|254780694|r  184 FELTGREVECLTW-ISEGKTSDEIAVILGISRNTVNNYIASIMRKTA  229 (246)
Q Consensus       184 ~~LT~RE~eVl~l-ia~G~t~~eIA~~L~iS~~TV~~hl~~i~~KLg  229 (246)
T Consensus       140 ~~L~e~~REvi~LR~~EGLS~~EvA~~Md~~~~av~~l~~Ral~~Lr  186 (190)
T TIGR02984       140 AKLPEDYREVILLRHLEGLSFAEVAERMDRSEGAVSMLWVRALARLR  186 (190)
T ss_pred             HHCCHHHHHHHHHHHHHCCCHHHHHHHHCCCHHHHHHHHHHHHHHHH
T ss_conf             64792258999998760355589998707975898758999999998