A DNA binding protein from the extreme thermophile Thermus thermophilus

A comparative study of ribosomal and DNA binding protein II from two thermophilic bacteria, Bacillus caldolyticus strain EP 00275 and Bacillus stearothermophilus

Ribosomal and DNA binding proteins (DNA bp II) from an extreme thermophilic bacterium, B. caldolyticus strain EP 00275, were investigated for stability and crystallization and compared to the homologous proteins from B. stearothermophilus. Two-dimensional gel electrophoresis of both types of proteins, the amino acid composition and the sequences of some of the peptides of DNA bp II revealed a close relationship between each other. The physico-chemical characteristics of DNA bp II were similar but different from homologous proteins from T. thermophilus and C. pasteurineum. From our results we conclude: B. stearothermophilus and B. caldolyticus strain EP 00275 are similar organisms with regard to their ribosomal and DNA binding proteins.

The primary structure of DNA binding protein II from the extreme thermophilic bacterium Thermus thermophilus

The primary structure of DNA binding protein II (DNA bp II) from the extreme thermophilic bacterium Thermus thermophilus has been established by combination of manual and automated techniques. The protein has 95 residues and a molecular mass of 11,843. Comparison of the primary structure with the known sequence data of DNA bp II from Clostridium pasteurineum, Baccillus stearothermophilus, Escherichia coli, Rhizobium meliloti, Anabena, Thermoplasma acidophilum, Pseudomonas aeruginosa and Bacillus caldolyticus reveals a clear homology among these small basic proteins. In particular, two short sequences in the middle and C-terminal part of the proteins (residues N-Gly-Phe-Gly-X-Phe and Pro-X-Thr at positions 46-51 and 63-65, respectively) are completely conserved.

Characterization of the chromosomal protein MC1 from the thermophilic archaebacterium Methanosarcina sp. CHTI 55 and its effect on the thermal stability of DNA

In the deoxyribonucleoprotein complex of Methanosarcina sp. CHTI 55, DNA is associated with two proteins, named MC1 (methanogen chromosomal protein 1) (Mr 10,760) and MC2 (Mr 17,000). Protein MC1, the most abundant of these proteins, is closely related to the Methanosarcina barkeri MS protein MC1. The effect of Methanosarcina sp. CHTI 55 protein MC1 on the thermal stability of DNA has been studied in native deoxyribonucleoprotein complex, as well as in reconstituted complexes, and it has been compared to the effect of E. coli DNA-binding protein II. Both proteins are able to protect DNA against thermal denaturation, but the differences observed in the melting profiles suggest that they interact by different mechanisms. Moreover, our studies indicate that one molecule of protein MC1 protects eight base pairs of DNA.