ABSTRACT
Mitochondrial genome has undergone significant reduction in a course of evolution; however, it still contains a set of protein-encoding genes and requires translational machinery for their expression. Mitochondrial translation is of the prokaryotic type with several remarkable differences. This review is dedicated to one of the most puzzling features of mitochondrial protein synthesis, namely, the system of translational activators, i.e., proteins that specifically regulate translation of individual mitochondrial mRNAs and couple protein biosynthesis with the assembly of mitochondrial respiratory chain complexes. The review does not claim to be a comprehensive analysis of all published data; it is rather focused on the idea of the "core component" of the translational activator system.
Subject(s)
Mitochondria/metabolism , Saccharomyces cerevisiae/metabolism , Cytochromes b/genetics , Cytochromes b/metabolism , Electron Transport Complex IV/genetics , Electron Transport Complex IV/metabolism , Mitochondria/genetics , Mitochondrial Proteins/genetics , Mitochondrial Proteins/metabolism , RNA, Messenger/metabolism , Saccharomyces cerevisiae Proteins/genetics , Saccharomyces cerevisiae Proteins/metabolism , Transcriptional ActivationABSTRACT
Anaerobic thermophilic archaea of the genera Thermogladius and Desulfurococcus capable of a- and P3-keratin decomposition were isolated from hot springs of Kamchatka and Kunashir Island. For two of them (strains 2355k and 3008g), the presence of high-molecular mass, cell-bound endopeptidases active against nonhydrolyzed and partially hydrolyzed proteins at high values of temperature and pH was shown. Capacity for ß-keratin decomposition was also found in collection strains (type strains of Desulfurococcus amylolyticus subsp. amylolyticus, D. mucosus subsp. mobilis, and D. fermentans).
Subject(s)
Crenarchaeota/metabolism , Keratins/metabolism , beta-Keratins/metabolism , Anaerobiosis , Crenarchaeota/growth & development , Crenarchaeota/isolation & purification , Desulfurococcaceae/isolation & purification , Desulfurococcaceae/metabolism , Endopeptidases/metabolism , Hot Springs/microbiology , Hydrogen-Ion Concentration , Hydrolysis , TemperatureABSTRACT
The complete genomic sequence of a novel hyperthermophilic crenarchaeon, strain 1910b(T), was determined. The genome comprises a 1,750,259-bp circular chromosome containing single copies of 3 rRNA genes, 43 tRNA genes, and 1,896 protein-coding sequences. In silico genome-genome hybridization suggests the proposal of a novel species, "Thermofilum adornatus" strain 1910b(T).
