| sulfur-inhibited thermosphaera aggregans sp. nov., a new genus of hyperthermophilic archaea isolated after its prediction from environmentally derived 16s rrna sequences. | recently, a new procedure was developed which allowed for the first time the isolation of a hyperthermophilic archaeum tracked by 165 rrna analysis from a terrestrial hot solfataric spring ('obsidian pool', yellowstone national park, wy, usa). this novel isolate is characterized here. cells are round cocci with a diameter of 0.2-0.8 micron, occurring singly, in pairs, short chains and in grape-like aggregates. the aggregates exhibit a weak bluish-green fluorescence under uv radiation at 420 nm. ... | 1998 | 9542073 |
| crystal structure of the beta-glycosidase from the hyperthermophile thermosphaera aggregans: insights into its activity and thermostability. | the glycosyl hydrolases are an important group of enzymes that are responsible for cleaving a range of biologically significant carbohydrate compounds. structural information on these enzymes has provided useful information on their molecular basis for the functional variations, while the characterization of the structural features that account for the high thermostability of proteins is of great scientific and biotechnological interest. to these ends we have determined the crystal structure of ... | 1999 | 10094493 |
| activity of hyperthermophilic glycosynthases is significantly enhanced at acidic ph. | we have previously shown that the hyperthermophilic glycosynthase from sulfolobus solfataricus (ssbeta-glye387g) can promote the synthesis of branched oligosaccharides from activated beta-glycosides, at ph 6.5, in the presence of 2 m sodium formate as an external nucleophile. in an effort to increase the synthetic potential of hyperthermophilic glycosynthases, we report a new method to reactivate the ssbeta-glye387g glycosynthase and two novel mutants in the nucleophile of the beta-glycosidases ... | 2003 | 12859194 |
| a comparative infrared spectroscopic study of glycoside hydrolases from extremophilic archaea revealed different molecular mechanisms of adaptation to high temperatures. | the identification of the determinants of protein thermal stabilization is often pursued by comparing enzymes from hyperthermophiles with their mesophilic counterparts while direct structural comparisons among proteins and enzymes from hyperthermophiles are rather uncommon. here, oligomeric beta-glycosidases from the hyperthermophilic archaea sulfolobus solfataricus (ss beta-gly), thermosphaera aggregans (ta beta-gly), and pyrococcus furiosus (pf beta-gly), have been compared. studies of ftir sp ... | 2007 | 17357157 |
| complete genome sequence of thermosphaera aggregans type strain (m11tl). | thermosphaera aggregans huber et al. 1998 is the type species of the genus thermosphaera, which comprises at the time of writing only one species. this species represents archaea with a hyperthermophilic, heterotrophic, strictly anaerobic and fermentative phenotype. the type strain m11tl(t) was isolated from a water-sediment sample of a hot terrestrial spring (obsidian pool, yellowstone national park, wyoming). here we describe the features of this organism, together with the complete genome seq ... | 2010 | 21304709 |
| discovery of permuted and recently split transfer rnas in archaea. | abstract: background: as in eukaryotes, precursor transfer rnas in archaea often contain introns that are removed in trna maturation. two unrelated archaeal species display unique pre-trna processing complexity in the form of split trna genes, in which 2-3 segments of trnas are transcribed from different loci, then trans-spliced to form a mature trna. another rare type of pre-trna, found only in eukaryotic algae, is permuted, where the 3' half is encoded upstream of the 5' half, and must be proc ... | 2011 | 21489296 |