The Life Story of Hydrogen Peroxide III: Chirality and Physical Effects at the Dawn of Life

Abstract

It is a remarkable observed fact that all life on Earth is homochiral, its biology using exclusively the D-enantiomer of ribose, the sugar moiety of the ribonucleic acids, and the L-enantiomers of the chiral amino acids. Motivated by concurrent work that elaborates further the role of hydrogen peroxide in providing an oscillatory drive for the RNA world (Ball & Brindley 2015a, J. R. Soc. Interface 12, 20150366, and Ball & Brindley 2015b, this journal, in press), we reappraise the structure and physical properties of this small molecule within this context. Hydrogen peroxide is the smallest, simplest molecule to exist as a pair of non-superimposable mirror images, or enantiomers, a fact which leads us to develop the hypothesis that its enantiospecific interactions with ribonucleic acids led to enantioselective outcomes. We propose a mechanism by which these chiral interactions may have led to amplification of D-ribonucleic acids and extinction of L-ribonucleic acids.

Molecular model for chirality phenomena

“…In this work, we present a simple three-dimensional continuum molecular model system for chirality phenomena. Inspired by the smallest chiral molecule in nature, hydrogen peroxide, [46][47][48] we developed a tetramer model that exhibits tunable chiral interactions, chiral amnesia, as well as solidphase chiral behavior, all of which are relevant features for chiral symmetry breaking. In Sec.…”

Reaching multi‐nanosecond timescales in combined QM/MM molecular dynamics simulations through parallel horsetail sampling

“…[60] Hydrogen peroxide has also been claimed to be a fundamental species related to the origin of chirality in the living world. [61] A fundamental structural property of H 2 O 2 is its skew or gauche conformation, resulting from the hyperconjugation interaction between the occupied non-bonding orbital of one oxygen atom and the unoccupied r* orbital on the OH bond of the adjacent O atom. The hyperconjugation effect (which is also present in higher polyoxides [62] ) would favor a structure with a HOOH dihedral angle d 5 6908.…”

Molecules to Microbes

“…There are three main strands to the hypothesis, namely that (a) as an oxidation of the thiosulfate/hydrogen peroxide (THP) redox oscillator, thereby providing a periodic power source; (b) HP may act as an agent of molecular change and evolution, and mediator of homochirality; and (c) the THP oscillator is subject to Brownian input perturbations and is life-enabling, as it produces a weighted distribution of output of thermal fluctuations that favours polymerisation and chemical diversification over chemical degradation and simplification. The HP crucible hypothesis can help to clarify the hero and villain roles of HP in cell function and can explain the singularity of life: of necessity, life evolved an armoury of catalases early on, the continuing and all-pervasive presence of which prevents HP from accumulating anywhere in sufficient quantities to host a second origin [7][8][9]. Helen Hansma (University of California at Santa Barbara) posited that life might have started between sheets of mica, powered by the mechanical energy (mechanochemistry) of moving mica sheets.…”