Methanothermus fervidus

The dogma that glycoproteins occur exclusively in eucaryotic cells had to be revised in the last twenty years. Bacterial glycoproteins form the outer surface (S)-layer of archae- and eubacteria [61,62]. In analogy to eucaryotic cells, partly sulfated oligosaccharides attached to Asn or Thr are found in halobacteria. Nucleoside-diphosphate-activated oligosaccharides were identified as intermediates in the biosynthesis of the S-layer of the eubacterium Bacillus alvei [63] and the archaebacterium Methanothermus fervidus [64],... 

Sandman K, Krzycki JA, Dobrinski B, Lurz R, Reeve IN, HMf, a DNA-binding protein isolated from the hyperthermophilic archaeon Methanothermus fervidus, is most closely related to histones. Proc. Natl. Acad. Sci. U.S.A. 1990 87 5788-5791. 

Fig. 1. Thin section of Methanothermus fervidus (symbols S, S-layer Ps, pseudomurein sacculus ...

Chemical structure and biosynthesis of the S-layer glycoprotein of Methanothermus fervidus... 

B) - Putative alignment of eukaryotic histones with Methanothermus fervidus protein HMf... 

Concensus sequences of eukaryotic histones, from ref.22, HMf, Methanothermus fervidus... 

Fig. 3. Binding of HMf protein from Methanothermus fervidus to pUC18-DNA. (Adapted from ref [23].) Panel A shows the stronger binding of HMf to super-coiled DNA compared to open circular or linear DNA. Panel B shows the small loops found with unfixed material. Panel C shows the formation of nucleosome-like structures on linearized fragments with fixation of glutaraldehyde. The bar in panel B represents 0.5 pm. Courtesy R. Lurz.

The number of rRNA operons in archaea is always small. Haloferax vol-canii, Methanobacterium thermoautotrophicum and Methanothermus fervidus have two, and Methanobacterium vannielii has four (reviewed by Brown et al. [5]). On the basis of Southern transfers of pulsed field gels, Sanz et al. [106] report that the halophilic archaea have from one to four rRNA operons Haloarcula californiae, 4 Haloferax gibbonsii, 4 Halobacterium halobium NCMB 111, 3 Halobacterium marismortui, 3 Halococcus morrhuae, 2 and Halobacterium salinarium, 1. Bacteria have from one to eleven copies (e.g.. Bacillus subtilis, 11 [107] Escherichia coli, 7 [108], and Mycoplasma pneumoniae, 1 [109]). In Halobacterium halobium, the presence of only one rRNA operon facilitated the isolation of strains with mutated 23S rRNA genes, which are resistant to thiostrepton [110], anisomycin [111] or chloramphenicol [112]. 

---