![The original role of proteins was to stabilize RNA, rather than to act as enzymes. (a) The peptidyl transferase center of the Escherichia coli ribosome [96]. The figure shows the RNA that forms the catalytic site, as identified by [97], with the three proteins that form the closest association with it: the large subunit proteins L2 (red), L4 (green) and L15 (magenta). All of these have substantial non-globular parts, which are the parts in contact with the RNA. The catalytic center is in the middle of the RNA helix. (b) The human 17S U2 snRNP involved in the first step of RNA splicing [98], showing the RNA core and the protein most closely associated with it (splicing factor 3b). Again, the part of the protein in contact with the RNA is lacking in regular secondary structure. -- LIFE via PubMed](https://i0.wp.com/astrobiology.com/wp-content/uploads/2025/06/Autocatalytic-Selection-As-A-Driver.png?resize=1200%2C720&ssl=1)
Darwin’s theory of evolution by natural selection was revolutionary because it provided a mechanism by which variation could be selected. This mechanism can only operate on living systems and thus […]
Charles Darwin
Posted inBiochemistry & Organic Chemistry, Biosignatures & Paleobiology, Genomics, Proteomics, Bioinformatics, Origin & Evolution of Life, Press Release
Modeling The Origins Of Life: New evidence For An RNA World
Charles Darwin described evolution as “descent with modification.” Genetic information in the form of DNA sequences is copied and passed down from one generation to the next. But this process […]
Posted inAstrochemistry, Astrogeology, Biochemistry & Organic Chemistry, Biogeochemical Cycles & Geobiology, Biosignatures & Paleobiology, Origin & Evolution of Life, Panspermia, Press Release
The Cosmic Fertiliser That Fuelled The Origins Of Life
The origin of life is an event so rare that, to the best of our knowledge, it has only happened once: here on Earth. The questions of how life developed […]
Posted inAstrobiology (general), Away Teams & Field Reports, Exploration Gear & Tech, Press Release
Two Hundred Years After Darwin’s Expedition DARWIN200 Embarks On A Two Year, 40,000 Mile Voyage
Editor’s note: As we embark on expeditions to seek out life on other worlds it is important to look back at the first truly global expeditions that sought to understand […]
Posted inAway Teams & Field Reports, Biogeochemical Cycles & Geobiology, Biosignatures & Paleobiology, Origin & Evolution of Life, Press Release
Away Team Expedition To The Galápagos – Discovering What Darwin Couldn’t See
Editor’s note: As you read this release about an expedition to the Galápagos Islands think about how you’d conduct a systematic assay of new life forms as part of an […]
Posted inBiosignatures & Paleobiology, Mars, Missions & Hardware, Press Release
Discoveries about life on Earth inspire Beagle 2
The nineteenth century spirit of discovery is inspiring the effort to land the first probe on Mars in the twenty first century. Last week, as if to give the inspiration […]