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The chemical origin of life refers to the conditions that might have existed and therefore promoted the first replicating life forms. It considers the physical and chemical reactions that could have led to early replicator molecules.
The discovery of an alternative squalene epoxidase (AltSQE) belonging to the fatty acid hydroxylase superfamily in the diatom Phaeodactylum tricornutum and other eukaryotic lineages solves the mystery of the existence of a steroid biosynthesis pathway in eukaryotes that lack the canonical flavoprotein SQE.
Arabinonucleic acid (ANA) Watson-Crick base-pair with RNA/DNA and can evolve to display enzyme-like function. Here, the authors now identify a prebiotic pathway that yields the complete set of Watson-Crick base-pairing purine and pyrimidine ANA nucleosides.
Extraterrestrial sources may have provided prebiotic phosphorus to the early Earth. Here, the authors investigate the potential of phosphine-doped astrochemical analog ices to form phosphorus oxoacids as precursors to more complex prebiotic compounds.
The simplest sugar—glycolaldehyde—has recently been detected in space and now a mechanistic rationale for its formation is presented, which includes its onward reaction to the next higher aldose, glyceraldehyde. The key species in the chemistry at play is the formaldehyde isomer hydroxymethylene, which reacts with the carbonyl component in an essentially barrierless carbonyl–ene-type reaction.
The bioenergetic metabolism of all life today depends on proton gradients; however, it remains unclear how such gradients developed in early life. Here, Mansy and co-workers establish a possible prebiotic mechanism in which iron–sulfur peptide redox networks generate a trans-membrane pH gradient.