amino acids Archives

Astrochemistry, Biochemistry & Organic Chemistry, Biogeochemical Cycles & Geobiology, Biosignatures & Paleobiology, Enceladus, Icy Worlds, Status Report, Water/Hycean Worlds & Oceanography

The Behavior of Organics in Rapidly Frozen Brine With Relevance To Enceladus

by Keith CowingNovember 25, 2023November 25, 2023

NASA-supported scientists have provided new information about the behavior of organic molecules frozen in brine (e.g. salty water) under conditions similar to the surface of Saturn’s moon Enceladus. The results […]

the question arises─before these enzymes evolved, how were primordial tRNAs selectively aminoacylated?

Biochemistry & Organic Chemistry, Genomics, Proteomics, Bioinformatics, Origin & Evolution of Life, Status Report

Triplet-Encoded Prebiotic RNA Aminoacylation

by Keith CowingNovember 22, 2023November 22, 2023

The encoding step of translation involves attachment of amino acids to cognate tRNAs by aminoacyl-tRNA synthetases, themselves the product of coded peptide synthesis. So, the question arises─before these enzymes evolved, […]

Schematic for reactions in space occurring in the gas phase (top), and on the surface of grains (bottom). -- NASA

Astrochemistry, Biochemistry & Organic Chemistry, Biosignatures & Paleobiology, Interstellar, Status Report

Density Functional Theory Calculations on the Interstellar Formation of Biomolecules

by Keith CowingOctober 24, 2023October 24, 2023

The density functional theory (DFT) is the most versatile electronic structure method used in quantum chemical calculations, and is increasingly applied in astrochemical research.

Simulated nicotinic acid abundances compared to measured values in carbonaceous chondrites and asteroid (162173) Ryugu. A rock density of 3 g cm−3 , a porosity of 0.2, [56–58] and an ice density of 0.917 g cm−3 completely filling the pores (after all radionuclides have decayed and aqueous activity has ceased) were assumed as the properties of the planetesimal/carbonaceous chondrite hosting the chemical synthesis. The simulations were run at a pressure of 100 bar. From left to right, the plotted bars show the simulated molecular abundance of nicotinic acid (solid black line on the very left) for the whole temperature range of liquid water, as well as the abundances measured in samples of Cb asteroid (162173) Ryugu collected during the Hayabusa2 spacecraft mission, [14] in the CI chondrite Orgeil, [14] several Antarctic CM2 chondrites, [12] the CM2 chondrites Murchison and Murray, and the ungrouped C2 chondrite Tagish Lake [13] as lines and shaded ranges described in the legend. Each time, the measured nicotinic acid abundance and the sum of all isomers (nicotinic acid, isonicotinic acid, picolinic acid) are given, since thermochemical equilibrium simulations cannot distinguish between isomers. The type of extraction method used (hot water, cold water ultrasonication, HCl-hydrolyzed, formic acid) is denoted next to each panel. A tabulated version of the data presented here is available in the Supporting Information in Table S1. -- astro-ph.EP

Astrochemistry, Biochemistry & Organic Chemistry, Comets and Asteroids, Genomics, Proteomics, Bioinformatics, Imaging & Spectroscopy, Meteorites & Asteroids, Origin & Evolution of Life, Status Report

Prebiotic Vitamin B3 Synthesis In Carbonaceous Planetesimals

by Keith CowingOctober 19, 2023October 19, 2023

Aqueous chemistry within carbonaceous planetesimals is promising for synthesizing prebiotic organic matter essential to all life.

The amino acid selenocysteine - Wikipedia

Astrochemistry, Biochemistry & Organic Chemistry, Genomics, Proteomics, Bioinformatics, Press Release

A New Synergistic Method Can Create Non-canonical Amino Acids By Merging Synthetic Photochemistry With Biocatalysis

by Keith CowingJuly 31, 2023July 31, 2023

New chemistry, new enzymology. With a new method that merges the best of two worlds — the unique and complementary activities of enzymes and small-molecule photochemistry — researchers at UC […]

GC chromatogram of carboxylic acids formed by spark discharge in the gas mixture of CO2, CH4, N2, and H2O (rCH4 = 0.25). The sample was analyzed without hydrolysis. C1: formic acid, C2: acetic acid, C3: propanoic acid, iC4: isobutyric acid, C4: butyric acid, iC5: isovaleric acid. -- Life

Atmospheres, Climate, Weather, Biochemistry & Organic Chemistry, Biogeochemical Cycles & Geobiology, Biosignatures & Paleobiology, Origin & Evolution of Life, Press Release

Formation of Amino Acids and Carboxylic Acids in Weakly Reducing Planetary Atmospheres by Solar Energetic Particles from the Young Sun

by Keith CowingMay 31, 2023May 26, 2023

Life most likely started during the Hadean Eon; however, the environmental conditions which contributed to the complexity of its chemistry are poorly known.

Volume-adjusted proximity probability distributions for a select different combinations of amino acids and nucleotides. Proximity is the closest atom of the nucleotide to the closest atom of the closest of 10 amino acids in the 40 Å periodic box. Proportion of simulation time is adjusted for the volume of the amino acid and nucleotide, so that different systems are comparable. Most interactions demonstrate multiple binding modes, at ~1.9 Å, 2.5 Å, and 4 Å. An additional peak at around 5.5 Å is also visible, which is interpreted as the average distance of the closest amino acid when not bound. The vertical red line indicates the 5 Å threshold for binding. (A) proline; (B) arginine; (C) aspartate; (D) phenylalanine; (E) glycine. -- Life

Biophysics, Genomics, Proteomics, Bioinformatics, Origin & Evolution of Life, Status Report

Biophysical Interactions Underpin the Emergence of Information in the Genetic Code

by Keith CowingMay 30, 2023May 26, 2023

The genetic code conceals a ‘code within the codons’, which hints at biophysical interactions between amino acids and their cognate nucleotides. Yet, research over decades has failed to corroborate systematic […]

Minimal autotrophic protometabolism. The network presents a chemically focused set of reactions which have universal or ancient conservation across all domains of life. The network is oriented around a pH gradient-catalysed CO2 fixation pathway with chemical similarity to the acetyl-CoA pathway and extends to the essential amino acids, nucleotides, and cofactors required in modern metabolisms. Major super-pathways have been colour-coded, and dashed lines represent pathways with poor conservation between bacterial and archaeal clades. -- Life

Biochemistry & Organic Chemistry, Origin & Evolution of Life, Status Report

Prebiotic Synthesis of Aspartate Using Life’s Metabolism as a Guide

by Keith CowingMay 29, 2023May 26, 2023

A protometabolic approach to the origins of life assumes that the conserved biochemistry of metabolism has direct continuity with prebiotic chemistry. One of the most important amino acids in modern […]

High enantiomeric excesses (ee’s) of l-amino acids, including non-proteinogenic amino acid isovaline (Iva), were discovered in the Murchison meteorite, but the detailed molecular mechanism responsible for the observed ee of amino acids remains elusive and inconsistent, because Iva has an inverted circular dichroism (CD) spectrum with respect to α-H amino acids, e.g., alanine. To address this issue, we resort to accurate ab initio calculations for amino acids and their precursors in the Strecker synthesis. We evaluated their photolysis-induced ee in the range 5–11 eV including the Lyman alpha emission line (Lyα), the typical intensive 10.2 eV radiation ascribed to the early phase of galactic evolution. We show that only the aminonitrile precursors are characterized by positive ee in the Lyα region, explaining why right-handed circularly polarized Lyα (R-CP-Lyα) induces homologous l-amino acids. This study shows that the homochirality of amino acids is produced at the aminonitrile precursors stage.-- The Journal of Physical Chemistry Letters

Astrochemistry, Biochemistry & Organic Chemistry, Meteorites & Asteroids, Press Release

New Study Provides Novel Insights Into The Cosmic Evolution Of Amino Acids

by Keith CowingMay 26, 2023

All biological amino acids on Earth appear exclusively in their left-handed form, but the reason underlying this observation is elusive.

A representative texture of the Ryugu particle (A0022). (a) An optical image of an entire view of the particle. The rough and irregular surface is finely cracked, resulting in the particle being fragile in nature. (b) A back-scattered electron image of a cross section of the particle. Several µm to 10’s of µm-sized carbonates (mainly dolomite), Fe-oxides (e.g., magnetite), and Fe-sulfides (e.g., pyrrhotite) are widespread in the phyllosilicate-dominated matrix (smectite and serpentine), which also includes sub-µm-sized organic matter, Fe-sulfide, carbonate, and phosphate minerals. -- Okayama University

Astrochemistry, Astrogeology, Biochemistry & Organic Chemistry, Biosignatures & Paleobiology, Comets and Asteroids, Genomics, Proteomics, Bioinformatics, Origin & Evolution of Life, Press Release

How Were Amino Acids Formed Before The Origin Of Life On Earth?

by Keith CowingApril 5, 2023April 5, 2023

Our solar system formed from a molecular cloud, which was composed of gas and dust that was emitted into the interstellar medium (ISM), a vast space between stars. On collapse […]