A novel hyperthermophilic strictly chemolithoautotrophic member of the genus Methanococcus was isolated from a shallow (depth: 106 m) submarine vent system at the Kolbeinsey ridge, Iceland. The isolate grew between 45 and 91 degrees C with an optimum around 88 degrees C (doubling time: 25 min). It differs from Methanococcus jannaschii in its 16S rRNA sequence, its non-hybridizing DNA, and its selenium-independent growth. Therefore, the isolate represents a new species which we name Methanococcus igneus. Type strain is isolate "Kol 5" (DSM 5666).
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http://dx.doi.org/10.1016/s0723-2020(11)80197-9 | DOI Listing |
Biochemistry
March 2016
Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, United States.
Thiamin diphosphate is an essential cofactor in all forms of life and plays a key role in amino acid and carbohydrate metabolism. Its biosynthesis involves separate syntheses of the pyrimidine and thiazole moieties, which are then coupled to form thiamin monophosphate. A final phosphorylation produces the active form of the cofactor.
View Article and Find Full Text PDFNucleic Acids Res
January 2013
Gene Center and Department of Biochemistry, Ludwig-Maximilians-Universität München, Feodor-Lynen-Str. 25, 81377 Munich, Germany.
In all living cells, protein synthesis occurs on ribonucleoprotein particles called ribosomes. Molecular models have been reported for complete bacterial 70S and eukaryotic 80S ribosomes; however, only molecular models of large 50S subunits have been reported for archaea. Here, we present a complete molecular model for the Pyrococcus furiosus 70S ribosome based on a 6.
View Article and Find Full Text PDFNucleic Acids Res
November 2001
Departments of Biochemistry and Medicinal Chemistry, University of Utah, Salt Lake City, UT 84112-5820, USA.
Post-transcriptional modifications in archaeal RNA are known to be phylogenetically distinct but relatively little is known of tRNA from the Methanococci, a lineage of methanogenic marine euryarchaea that grow over an unusually broad temperature range. Transfer RNAs from Methanococcus vannielii, Methanococcus maripaludis, the thermophile Methanococcus thermolithotrophicus, and hyperthermophiles Methanococcus jannaschii and Methanococcus igneus were studied to determine whether modification patterns reflect the close phylogenetic relationships inferred from small ribosomal subunit RNA sequences, and to examine modification differences associated with temperature of growth. Twenty-four modified nucleosides were characterized, including the complex tricyclic nucleoside wyosine characteristic of position 37 in tRNA(Phe) and known previously only in eukarya, plus two new wye family members of presently unknown structure.
View Article and Find Full Text PDFA new method for theoretical analysis of the molecular phylogeny of bacteria, successfully applied earlier to nitrifying bacteria, was used to study the molecular phylogeny of methanogenic archaebacteria. The group studied included Methanococcus igneus, Methanococcus vannielii, Methanothermus fervidus, Methanolobus tindarius, Methanobacterium formicicum, Methanosarcina barkeri, Methanobacterium thermoformicicum, Methanoplanus limicola, Methanospirillum hungatei, and Methanobacterium thermoautotrophicum. Based on the hypothesis that direct linear regression always exists between evolutionary changes in the DNA G + C content and the primary structure of rRNA, the branching order of the phylogenetic tree of methanogenic archaebacteria was determined.
View Article and Find Full Text PDFJ Biol Chem
October 1999
Department of Microbiology, University of Illinois, Urbana, Illinois 61801, USA.
Adenylate kinases (ADKs) from four closely related methanogenic members of the Archaea (the mesophile Methanococcus voltae (MVO), the thermopile Methanococcus thermolithotrophicus (MTH), and the extreme thermopiles Methanococcus igneus (MIG) and Methanococcus jannaschii (MJA)) were characterized for their resistance to thermal denaturation. Despite possessing between 68 and 81% sequence identity, the methanococcal ADKs significantly differed in their stability against thermal denaturation, with melting points ranging from 69 to 103 degrees C. The high sequence identity between these organisms allowed regions of the MVO and MJA ADKs to be exchanged, producing chimeric ADKs with significantly altered thermal stability.
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