Search results for "Eukaryotic Ribosome"
showing 4 items of 4 documents
Discovery of a Pederin Family Compound in a Nonsymbiotic Bloom-Forming Cyanobacterium
2018
The pederin family includes a number of bioactive compounds isolated from symbiotic organisms of diverse evolutionary origin. Pederin is linked to beetle-induced dermatitis in humans, and pederin family members possess potent antitumor activity caused by selective inhibition of the eukaryotic ribosome. Their biosynthesis is accomplished by a polyketide/nonribosomal peptide synthetase machinery employing an unusual trans-acyltransferase mechanism. Here, we report a novel pederin type compound, cusperin, from the free-living cyanobacterium Cuspidothrix issatschenkoi (earlier Aphanizomenon). The chemical structure of cusperin is similar to that of nosperin recently isolated from the lichen cya…
Ribosome Heterogeneity in Plant and Animal Organisms. Its Relationship to Ribosomal Ambiguity and to Ribosome Evolution
1970
Abstract The data presented and discussed in this report summarize evidence showing that ribosomes isolated from several eucaryotic (plant and animal) organisms exhibit ample variations of the composition of their protein moiety and that the degree of dissimilarity correlates with the degree of taxonomic kinship of the organisms from which the ribosomes were derived. They also provide evidence that (a) the 80-S ribosomes isolated from the cytoplasmic matrix of higher plants and yeast and the 70-S ribosomes derived from both chloroplasts and mitochondria are endowed with highly dissimilar protein complements, (b) the organellar (67-S) ribosomes derived from the chloroplasts of more or less d…
Evolutionary implications of intron-exon distribution and the properties and sequences of the RPL10A gene in eukaryotes.
2013
The RPL10A gene encodes the RPL10 protein, required for joining 40S and 60S subunits into a functional 80S ribosome. This highly conserved gene, ubiquitous across all eukaryotic super-groups, is characterized by a variable number of spliceosomal introns, present in most organisms. These properties facilitate the recognition of orthologs among distant taxa and thus comparative studies of sequences as well as the distribution and properties of introns in taxonomically distant groups of eukaryotes. The present study examined the multiple ways in which RPL10A conservation vs. sequence changes in the gene over the course of evolution, including in exons, introns, and the encoded proteins, can be…
On the function of modified nucleosides in the RNA world.
1998
Presumably ribosome and transfer RNA (tRNA) evolved from a pre-existing function in the RNA stage of life and were secondarily adapted for protein synthesis. Various possible initial functions of the primitive ribosome (protoribosome) have been suggested. The initial function of the primitive ribosome and primitive genetic translation would have been quite similar. It is possible that, initially, both functions coexisted in the protoribosome. Given that the three-dimensional structure of ribosomal RNAs shows only minor variations throughout time, it is, then, most likely that present ribosomes can still recall (remember) the most important parts of the mechanism of their initial function. A…