enzymes Archives - Astrobiology

In a water–water hydrogen bond, a hydrogen nucleus from one water molecule is donated to an sp3 lone pair on the oxygen atom of a neighboring water molecule, along the axis of the O–H covalent bond. The polar O–H bond withdraws electron density from the hydrogen atom, exposing the back of the proton to HB acceptor. -- Protein Science via PubMed

Biochemistry & Organic Chemistry, Biophysics, Biosignatures & Paleobiology, Genomics, Proteomics, Bioinformatics, Habitable Zones, Origin & Evolution of Life, Status Report, Water/Hycean Worlds & Oceanography

The Master Molecule That Built Biology: How Water Shaped The Chemistry Of Life

by Keith CowingApril 25, 2026April 25, 2026

The deep entanglement of biomolecular structure and function with aqueous systems supports the view that water actively sculpted both molecules and processes during the origins of life and continues to […]

The four helices conserved across the Lipocone superfamily constitute a cone-like structure, with the helices tending to coalesce on one end and open out into a pocket on the other, lined by the conserved sequence positions. Image credit: Burroughs, Nicastro and L. Aravind (CC BY 4.0)

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

Origins Of Wnt Signalling Reveals A Protein Superfamily Across The Tree of Life

by Keith CowingSeptember 11, 2025September 18, 2025

Researchers have described a large set of previously unrecognised enzymatic domains – named the Lipocone superfamily – and outlined their evolutionary pathway from bacterial defence molecules to key players in […]

N-isotope fractionation values observed in this study compared to the sedimentary δ15N record a, and known ranges of extant microbial biomass b, The sedimentary database includes bulk rock δ15N (dark grey) and kerogen δ15N (light grey), from both marine and nonmarine rocks across a range of very low to moderate metamorphic grades22,39,40. The purple bar in a and b represents the average fractionation signature of all ancestors in this study and is largely coincident with the minimum d15N values seen in the rock record which are presumed to record nitrogen-fixation unaffected by subsequent nitrogen cycling. The partial range of bacterial and fractionation signatures are labeled as the modern range of N-isotopic values41 (see Figure S3 for extended range). -- biorxiv.org

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

Persistent Nitrogenase Isotope Signatures Over Two Billion Years Of Engineered Evolution

by Keith CowingJune 28, 2025

Nitrogen isotope fractionation (ε15N) in sedimentary rocks has provided evidence for biological nitrogen fixation, and thus primary productivity, on the early Earth.

Fluorescence microscopy video showing vesicle formation -- University of California - San Diego

Biochemistry & Organic Chemistry, Biophysics, Biosignatures & Paleobiology, Genomics, Proteomics, Bioinformatics, Origin & Evolution of Life, Press Release

How The First Cell Membranes Came To Exist

by Keith CowingNovember 14, 2024

Few questions have captivated humankind more than the origin of life on Earth. How did the first living cells come to exist? How did these early protocells develop the structural […]

Graphical Abstract -- ACS

Astrochemistry, Biochemistry & Organic Chemistry, Biophysics, Biosignatures & Paleobiology, Genomics, Proteomics, Bioinformatics, Origin & Evolution of Life, Status Report

Pinpointing Conditions for a Metabolic Origin of Life: Underlying Mechanisms and the Role of Coenzymes

by Keith CowingOctober 14, 2024October 14, 2024

Famously found written on the blackboard of physicist Richard Feynman after his death was the phrase, “What I cannot create, I do not understand.” From this perspective, recreating the origin […]

Open and closed conformations of rcPEPCK along the reaction coordinate. Superposition of the open and closed structures (N-terminal domain residues 3-250) of rcPEPCK, indicating conformational changes of A) the global structure and B) the active site. Holo rcPEPCK (open) is shown in steel blue (PDB 2QEW), and its Ω-loop in light grey, R-loop in coral, and P loop in lilac. Oxalate- (enol-pyruvate intermediate mimic) GTP bound rcPEPCK (closed) is shown in gold (PDB 3DT2) and its Ω-loop in grey, R-loop in firebrick red, and P-loop in purple. Oxalate9 and GTP are shown bound to the active site and atoms are colored by type (red – oxygen, blue – nitrogen, green – carbon, purple – phosphorous, pink – manganese). -- biorxiv.org

Biochemistry & Organic Chemistry, Biosignatures & Paleobiology, Extremeophiles and Extreme Environments, Microgravity, Status Report

A Structural Perspective on the Temperature-dependent Activity of Enzymes

by Keith CowingSeptember 3, 2024September 2, 2024

Enzymes are biomolecular catalysts whose activity varies with temperature. Unlike for small-molecule catalysts, the structural ensembles of enzymes can vary substantially with temperature, and it is in general unclear how […]

Exploring Extremes In The Search For Life On Mars Credit: Joseph Heili, Tanner Hoog, and Aaron Engelhart

Biochemistry & Organic Chemistry, Biophysics, Biosignatures & Paleobiology, Extremeophiles and Extreme Environments, Mars, Origin & Evolution of Life, Press Release

Exploring Extremes In The Search For Life On Mars

by Keith CowingMay 20, 2024May 20, 2024

People might assume the search for life on Mars ended when NASA’s first rovers sent back images of the planet’s barren, inhospitable surface. However, as scientists broaden their understanding of […]