Transcription Activation Mediated by a Cyclic AMP Receptor Protein from Thermus thermophilus HB8▿ §

The extremely thermophilic bacterium Thermus thermophilus HB8, which belongs to the phylum Deinococcus-Thermus, has an open reading frame encoding a protein belonging to the cyclic AMP (cAMP) receptor protein (CRP) family present in many bacteria. The protein named T. thermophilus CRP is highly homologous to the CRP family proteins from the phyla Firmicutes, Actinobacteria, and Cyanobacteria, and it forms a homodimer and interacts with cAMP. CRP mRNA and intracellular cAMP were detected in this strain, which did not drastically fluctuate during cultivation in a rich medium. The expression of several genes was altered upon disruption of the T. thermophilus CRP gene. We found six CRP-cAMP-dependent promoters in in vitro transcription assays involving DNA fragments containing the upstream regions of the genes exhibiting decreased expression in the CRP disruptant, indicating that the CRP is a transcriptional activator. The consensus T. thermophilus CRP-binding site predicted upon nucleotide sequence alignment is 5′-(C/T)NNG(G/T)(G/T)C(A/C)N(A/T)NNTCACAN(G/C)(G/C)-3′. This sequence is unique compared with the known consensus binding sequences of CRP family proteins. A putative −10 hexamer sequence resides at 18 to 19 bp downstream of the predicted T. thermophilus CRP-binding site. The CRP-regulated genes found in this study comprise clustered regularly interspaced short palindromic repeat (CRISPR)-associated (cas) ones, and the genes of a putative transcriptional regulator, a protein containing the exonuclease III-like domain of DNA polymerase, a GCN5-related acetyltransferase homolog, and T. thermophilus-specific proteins of unknown function. These results suggest a role for cAMP signal transduction in T. thermophilus and imply the T. thermophilus CRP is a cAMP-responsive regulator

Purification, crystallization and preliminary X-ray crystallographic analysis of ST1022, a putative member of the Lrp/AsnC family of transcriptional regulators isolated from Sulfolobus tokodaii strain 7

A putative member of the Lrp/AsnC family of transcriptional regulators, ST1022 from S. tokodaii strain 7, has been purified and crystallized in the absence and presence of the effector l-glutamine. A molecular-replacement solution was found using the FL11 transcriptional regulator from Pyrococcus sp. OT3 as a model and structural refinement is under way

Structure of a UPF0150-family protein from Thermus thermophilus HB8

The crystal structure of the hypothetical protein TTHA0281 from T. thermophilus HB8 has been determined at 1.9 Å resolution. The TTHA0281 protein forms a homotetramer in which each monomer adopts an α-β-β-β-α fold