Premium
Effects of Pressure and pH on the Hydrolysis of Cytosine: Implications for Nucleotide Stability around Deep‐Sea Black Smokers
Author(s) -
Lepper Christopher P.,
Williams Martin A. K.,
Penny David,
Edwards Patrick J. B.,
Jameson Geoffrey B.
Publication year - 2018
Publication title -
chembiochem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.05
H-Index - 126
eISSN - 1439-7633
pISSN - 1439-4227
DOI - 10.1002/cbic.201700555
Subject(s) - cytosine , uracil , nucleobase , chemistry , cytidine , hydrolysis , nucleotide , dna , volume (thermodynamics) , high pressure , organic chemistry , biochemistry , thermodynamics , enzyme , physics , gene
The relatively low chemical stability of cytosine compared with other nucleobases is a key concern in origin‐of‐life scenarios, but the effect of pressure on the rate of hydrolysis of cytosine to uracil remains unknown. Through in situ NMR spectroscopy measurements, it has been determined that the half‐life of cytosine at 373.15 K decreases from (18.0±0.7) days at ambient pressure (0.1 MPa) to (8.64±0.18) days at high pressure (200 MPa). This yields an activation volume for hydrolysis of (−11.8±0.5) cm 3 mol −1 ; a decrease that is similar to the molar volume of water (18.0 cm 3 mol −1 ) and consistent with a tetrahedral 3,3‐hydroxyamine transition‐state/intermediate species. Similar behaviour was also observed for cytidine. At both ambient and high pressures, the half‐life of cytosine decreases significantly as the pH decreases from 7.0 to 6.0. These results provide scant support for the notion that RNA‐based life forms originated in high‐temperature, high‐pressure, acidic environments.