DNA partitions into triplets under tension in the presence of organic cations, with sequence evolutionary age predicting the stability of the triplet phase

Amirhossein Taghavi, Paul van der Schoot, Joshua T. Berryman

Research output: Contribution to journalArticleAcademicpeer-review

4 Citations (Scopus)
74 Downloads (Pure)

Abstract

Using atomistic simulations, we show the formation of stable triplet structure when particular GC-rich DNA duplexes are extended in solution over a timescale of hundreds of nanoseconds, in the presence of organic salt. We present planar-stacked triplet disproportionated DNA (Σ DNA) as a possible solution phase of the double helix under tension, subject to sequence and the presence of stabilising co-factors. Considering the partitioning of the duplexes into triplets of base pairs as the first step of operation of recombinase enzymes like RecA, we emphasise the structure-function relationship in Σ DNA. We supplement atomistic calculations with thermodynamic arguments to show that codons for 'phase 1' amino acids (those appearing early in evolution) are more likely than a lower entropy GC-rich sequence to form triplets under tension. We further observe that the four amino acids supposed (in the 'GADV world' hypothesis) to constitute the minimal set to produce functional globular proteins have the strongest triplet-forming propensity within the phase 1 set, showing a series of decreasing triplet propensity with evolutionary newness. The weak form of our observation provides a physical mechanism to minimise read frame and recombination alignment errors in the early evolution of the genetic code.

Original languageEnglish
Article numbere15
Pages (from-to)e15
Number of pages13
JournalQuarterly Reviews of Biophysics
Volume50
DOIs
Publication statusPublished - 16 Nov 2017

Keywords

  • Base Pairing
  • Base Sequence
  • Codon/genetics
  • DNA/genetics
  • Evolution, Molecular
  • Genetic Code/drug effects
  • Models, Molecular
  • Organic Chemicals/pharmacology
  • RNA/genetics

Fingerprint

Dive into the research topics of 'DNA partitions into triplets under tension in the presence of organic cations, with sequence evolutionary age predicting the stability of the triplet phase'. Together they form a unique fingerprint.

Cite this