A cyanosulfidic origin of the Krebs cycle.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 34389542.
- Also identified by DOI 10.1126/sciadv.abh3981 and PMC identifier 8363140.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
The centrality of the Krebs cycle in metabolism has long been interpreted as evidence of its antiquity, and consequently, questions regarding its provenance, and whether it initially functioned as a cycle or not, have received much attention. The present report shows that prebiotic oxidation of α-hydroxy carboxylates can be achieved by UV photolysis of a simple geochemical species (HS<sup>-</sup>), which leads to α-oxo carboxylates that feature in the Krebs cycle and glyoxylate shunt. Further reaction of these products leads to almost all intermediates of the Krebs cycle proper, succinate semialdehyde bypass, and glyoxylate shunt. Fumarate, the missing Krebs cycle component, and the required α-hydroxy carboxylates can be provided by a highly related hydrogen cyanide chemistry, which also provides precursors for amino acids, nucleotides, and phospholipids.