Water and Life: The Medium is the Message

Abstract

Water, the most abundant compound on the surface of the Earth and probably in the universe, is the medium of biology, but is much more than that. Water is the most frequent actor in the chemistry of metabolism. Our quantitation here reveals that water accounts for 99.4% of metabolites in Escherichia coli by molar concentration. Between a third and a half of known biochemical reactions involve consumption or production of water. We calculated the chemical flux of water and observed that in the life of a cell, a given water molecule frequently and repeatedly serves as a reaction substrate, intermediate, cofactor, and product. Our results show that as an E. coli cell replicates in the presence of molecular oxygen, an average in vivo water molecule is chemically transformed or is mechanistically involved in catalysis ~ 3.7 times. We conclude that, for biological water, there is no distinction between medium and chemical participant. Chemical transformations of water provide a basis for understanding not only extant biochemistry, but the origins of life. Because the chemistry of water dominates metabolism and also drives biological synthesis and degradation, it seems likely that metabolism co-evolved with biopolymers, which helps to reconcile polymer-first versus metabolism-first theories for the origins of life.

‘Whole Organism’, Systems Biology, and Top-Down Criteria for Evaluating Scenarios for the Origin of Life

“…There are three points relevant to the issue of water and dehydration reactions we wish to make, and then a fourth in Section 7.3 . First, as we all know, water is essential for life [ 49 , 105 , 106 , 107 , 108 , 109 ]. Thus, an open question for the terrestrial scenarios is how did the synthesis of biomolecules via wet–dry cycles become transferred to permanently water-based cells, that is, how was the transition made from non-analog energy and material flow to analog flows, given the level of complexity inferred to have developed at the protocell stage prior to the advent of ribozymes and enzymes (criterion 7).…”

“…Long before the transition to Darwinian life, it seems likely that the vent microchambers were the sites of heterogeneous organic molecular syntheses where high concentrations of complex organic molecules, including polymers, could accumulate [ 107 , 165 , 166 , 167 ]. The prebiotic chemistry was complex, potentially with components without analogs in modern biology, but that nonetheless may have played an important role in the emergence of life.…”

Biocellulose for Treatment of Wastewaters Generated by Energy Consuming Industries: A Review

“…Throughout history, civilizations have been able to develop various types of water supply systems, water purification devices and wastewater treatment methods. Efforts to obtain abundant quality drinking water have been intensively encouraged over the past two hundred years, leading to an increase in human life expectancy around the world [31]. Throughout history, civilizations have been able to develop various types of water supply systems, water purification devices and wastewater treatment methods.…”

Differential Oligomerization of Alpha versus Beta Amino Acids and Hydroxy Acids in Abiotic Proto-Peptide Synthesis Reactions

“…It is possible that, around four billion years ago, a creative phase of pre-Darwinian chemical evolution pared down the number of potential building blocks to form oligomers and polymers with levels of functionally required for Darwinian processes [15,[19][20][21][22][23][24]. Numerous models have been proposed to explain various chemical and physical aspects of the origins of biopolymers [15,18,22,[25][26][27][28][29][30][31][32][33][34][35][36][37][38][39][40]. The chemistry of water and the condensation-dehydration of building blocks into chimeric metabolites, oligomers and polymers are important features of these models.…”