Deciphering the origins of life on a molecular level includes unravelling the numerous interactions that could occur between the most important biomolecules being the lipids, peptides and nucleotides. They were […]
Life as we know it relies on the interplay between catalytic activity and information processing carried out by biological polymers.
Cell-free protein synthesis (CFPS) is a rapidly maturing in vitro gene expression platform that can be used to transcribe and translate nucleic acids at the point of need, enabling on-demand […]
Life on Earth comes in many diverse forms, yet there are certain biological molecules that are used by all life, appearing in every living cell throughout history.
![Type II tRNA evolved via RNA ligation and a 9 nt internal deletion within ligated 3′- and 5′-acceptor stems [42]. Also, 3 31 nt minihelices (one D loop minihelix (magenta 17 nt core) and two anticodon stem-loop-stem minihelices (blue 17 nt core)) were fused by ligation for minihelix replication. The 93 nt tRNA precursor was processed by an internal 9 nt deletion (see below) within fused 3′-acceptor (yellow) and 5′-acceptor (green) stems. In the type II tRNA structure, the red arrow indicates the fusion of the magenta segment (17 nt D loop minihelix core; UAGCC repeat) and the green segment (5′-acceptor stem fragment; initially GGCGG). Abbreviations: SLS) stem-loop-stem; Ac) anticodon. Molecular graphics were created using ChimeraX [43]. -- Life](https://i0.wp.com/astrobiology.com/wp-content/uploads/2023/11/The331NucleotideMinihelix.png?resize=1200%2C720&ssl=1)
There are no theorems (proven theories) in the biological sciences. We propose that the 3 31 nt minihelix tRNA evolution theorem be universally accepted as one.
Recent findings in protein evolution and peptide prebiotic plausibility have been setting the stage for reconsidering the role of peptides in the early stages of life’s origin.
![Examples of prebiotic analogue conditions. (A) A boiling, hydrothermal pool on Mount Mutnovsky, an active volcano south of Petropavlovsk, Kamchatka, Russia. The author is pointing at a membranous froth produced by myristic acid added to the pool [4]. Photo credit: Tony Hoffman). (B) Hydrothermal water in Bumpass Hell on Mount Lassen, California (photograph by author). (C) Hydrothermal pools in Hell’s Gate, near Rotorua, New Zealand (Photograph by author). (D) Fly Geyser in the Black Rock playa of northern Nevada (credit: Bruce Damer). -- Life](https://i0.wp.com/astrobiology.com/wp-content/uploads/2023/09/Template.png?resize=1200%2C720&ssl=1)
The commonly supposed template-based format for RNA self-replication requires both duplex assembly and disassembly.
Life on Earth relies on mechanisms to store heritable information and translate this information into cellular machinery required for biological activity. In all known life, storage, regulation, and translation are […]
The chemical origin of life on Earth is a puzzle that scientists have been trying to piece together for decades. Many hypotheses have been proposed to explain how life came […]
![Chiral molecules can spin polarize magnetic surfaces due to the CISS effect. A. Electron density of a molecule approaching a surface is asymmetrically distributed and a transient charge dipole is created. Charge transport through chiral molecules is spin selective due to the CISS effect and therefore a spin-dipole along the chiral molecular axis accompanies this charge dipole. This transient spin dipole can couple with surface spins due to the spin-exchange interaction (J ≡ [E(↑↑) − E(↑↓)]) and spin polarize the surface along the chiral molecular axis. B. Schematic of the setup used in crystallization experiments for CD detection. Homochiral crystals of RAO are formed on magnetite from their enantiopure solution. These crystals align the magnetic domains under them and interact with the surface spins due to magnetic dipolar coupling—a weaker but longer range coupling compared to the spin-exchange interaction C. A sequence showing the effect of chiral molecules on the magnetic domains. 1 Initially, there is no net magnetization of the magnetic domains. 2 As a layer of RAO is forming, the spins underneath the layer align due to the strong spin-exchange interaction. This is an avalanche magnetization process: molecules align the surface spins and the aligned regions attract more molecules and get larger. 3 The mono-layer grows and covers more surface due to the attraction of chiral molecules to the aligned regions and crystal seeds start forming. 4 Crystals get larger and couple with the magnetic domains due to magnetic dipole-dipole interaction, Edd. D. If an external magnetic field, −→B, is applied, the domains outside the area covered by crystals magnetize. Yet the crystals preserve the magnetization of the domains under them as long as the energy of the dipolar coupling is larger than the magnetic energy. -- physics.chem-ph](https://i0.wp.com/astrobiology.com/wp-content/uploads/2023/06/Chirality.png?resize=1200%2C720&ssl=1)
Life is homochiral and homochirality is a fundamental feature of living systems on Earth. While the exact mechanism that led to homochirality is still not fully understood, any realistic scenario […]
