Biochemistry

The First Biological Machines: Exploring Peptides as Precursors to RNA in Life’s Origins — A Hypothesis of the Reverse Central Dogma

Authors: Hyunho Shin
Comments: 7 Pages.

The RNA world hypothesis, which posits that RNA was the first biomolecule capable of storing genetic information and catalyzing biochemical reactions, has long dominated theories on the origin of life (1). However, RNA's chemical instability under prebiotic conditions raises questions about its viability as the primary molecule in early life (2). This paper proposes that peptides, rather than RNA, may have functioned as the first biological machines. I introduce the hypothesis of the Reverse Central Dogma, suggesting a molecular evolution sequence of proteins > RNA > DNA. I hypothesize that simple peptides, particularly those with disulfide bonds, could have formed spontaneously and catalyzed primitive biochemical processes (3). Among potential candidates, the heat-stable toxin (HST) from Vibrio mimicus is a compelling model due to its thermal stability, 17-amino-acid length, and specific catalytic activity (4). HST comprises only ten types of amino acids (I, D, C, E, N, P, A, F, G, L), with the sequence "IDCCEICCNPA CFGCLN" (5). This research aims to determine whether peptides formed under prebiotic conditions can exhibit machine-like activity, interact cyclically, and functionally connect with RNA. Testing peptide formation and activity in simulated early Earth conditions may provide insight into the role of peptides as foundational biological machines that set the stage for RNA and DNA evolution.
Category: Biochemistry