Crucial importance of water structure modification on trimethylamine N -oxide counteracting effect at high pressure

Rahul Sarma, Sandip Paul

Research output: Contribution to journalArticle

23 Citations (Scopus)

Abstract

Penetration of water molecules into the protein interior under high hydrostatic pressure conditions, leading to protein structural transition, is a well-known phenomenon. The counteracting effect of a naturally occurring osmolyte, trimethylamine N-oxide (TMAO), against pressure-induced protein denaturation is also well-established. But, what is largely unknown is the mechanism by which TMAO counteracts this protein denaturation. So to provide a molecular level understanding of how TMAO protects proteins at high pressure, we report here molecular dynamics (MD) computer simulation results for aqueous solutions of N-methylacetamide (NMA) with different TMAO concentrations over a wide range of pressures relevant to protein denaturation. Hydration behavior of NMA is analyzed at different conditions chosen. It is observed that hydrostatic pressure leads to a significant compression of hydration shell of nonpolar groups and increases hydration number. The compression is relatively insignificant in the vicinity of hydrogen bonding sites. TMAO can prevent pressure-induced enhanced hydration of NMA molecules. Interaction of TMAO with NMA and the structural and dynamical properties of water (site-site radial distribution function, coordination number, hydrogen-bond number, and lifetime) are also investigated to find the origin of the counteracting action of TMAO. Our results confirm that TMAO and pressure have counteracting effects on the water structural and dynamical properties, giving an explanation as to how TMAO counteracts pressure-conferred denaturation of proteins.

Original languageEnglish (US)
Pages (from-to)677-689
Number of pages13
JournalJournal of Physical Chemistry B
Volume117
Issue number2
DOIs
StatePublished - Jan 17 2013
Externally publishedYes

Fingerprint

Oxides
oxides
Water
Denaturation
Proteins
biopolymer denaturation
water
Hydration
hydration
proteins
Hydrostatic pressure
hydrostatic pressure
Hydrogen bonds
Bond number
trimethyloxamine
Molecules
coordination number
radial distribution
Distribution functions
Molecular dynamics

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry
  • Materials Chemistry
  • Surfaces, Coatings and Films

Cite this

Crucial importance of water structure modification on trimethylamine N -oxide counteracting effect at high pressure. / Sarma, Rahul; Paul, Sandip.

In: Journal of Physical Chemistry B, Vol. 117, No. 2, 17.01.2013, p. 677-689.

Research output: Contribution to journalArticle

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