Functional identification of an anti-sigmaE factor from Thermus thermophilus HB8.
The TTHB212 gene from extremely thermophilic bacterium Thermus thermophilus HB8 forms an operon with the upstream sigE gene encoding an extracytoplasmic function sigma factor, sigma(E), the sole alternative sigma factor of this strain, on megaplasmid pTT27. The TTHB212 gene encodes a poorly conserved protein, which has been predicted to be a transmembrane one with N-terminal intracellular and C-terminal extracytoplasmic domains. The N-terminal domain of TTHB212 protein (TTHB212N) prevented sigma(E) from binding to RNA polymerase (RNAP) core enzyme in vitro, and TTHB212N bound sigma(E) in a molar ratio of 1:1 when both proteins were co-expressed in Escherichia coli. Furthermore, TTHB212N inhibited the transcription activity of RNAP-sigma(E) holoenzyme, but not that of the RNAP-sigma(A) one, in vitro. The expression of several genes that are under the control of sigma(E) was increased in a TTHB212 gene-disruptant strain. Thus, TTHB212 protein was identified as an anti-sigma(E) factor. These findings indicate that T. thermophilus HB8 has a regulatory system involving sigma(E) and anti-sigma(E) factors.
Sakamoto
Keiko
K
RIKEN SPring-8 Center, Harima Institute, 1-1-1 Kouto, Sayo, Hyogo 679-5148, Japan.
Agari
Yoshihiro
Y
Yokoyama
Shigeyuki
S
Kuramitsu
Seiki
S
Shinkai
Akeo
A
D001426:Bacterial Proteins / Q000737:chemistry / Q000378:metabolism*; D002999:Clone Cells; D012321:DNA-Directed RNA Polymerases; D017353:Gene Deletion; D015964:Gene Expression Regulation, Bacterial; D005798:Genes, Bacterial; D020035:Holoenzymes / Q000378:metabolism; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D018085:Regulon / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012808:Sigma Factor / Q000037:antagonists & inhibitors*; D016963:Thermus thermophilus / Q000235:genetics / Q000378:metabolism*; D014158:Transcription, Genetic
D001426:Bacterial Proteins; D020035:Holoenzymes; D012808:Sigma Factor; C063202:sporulation-specific sigma factors; D012321:DNA-Directed RNA Polymerases