title: Trimethylamine-N-oxide switches from stabilizing nature: A mechanistic outlook through experimental techniques and molecular dynamics simulation.
abstract: In adaptation biology of the discovery of the intracellular osmolytes, the osmolytes are found to play a central role in cellular homeostasis and stress response. A number of models using these molecules are now poised to address a wide range of problems in biology. Here, a combination of biophysical measurements and molecular dynamics (MD) simulation method is used to examine the effect of trimethylamine-N-oxide (TMAO) on stem bromelain (BM) structure, stability and function. From the analysis of our results, we found that TMAO destabilizes BM hydrophobic pockets and active site as a result of concerted polar and non-polar interactions which is strongly evidenced by MD simulation carried out for 250 ns. This destabilization is enthalpically favourable at higher concentrations of TMAO while entropically unfavourable. However, to the best of our knowledge, the results constitute first detailed unambiguous proof of destabilizing effect of most commonly addressed TMAO on the interactions governing stability of BM and present plausible mechanism of protein unfolding by TMAO.
authors.affiliation: Department of Chemistry, University of Delhi, Delhi-110 007, India.
authors.forename: Anjeeta
authors.initials: A
authors.lastname: Rani
authors.affiliation: Department of Chemistry, Indian Institute of Technology, New Delhi-110 016, India.
authors.forename: Abhilash
authors.initials: A
authors.lastname: Jayaraj
authors.affiliation: Department of Chemistry, Indian Institute of Technology, New Delhi-110 016, India.|Supercomputing Facility for Bioinformatics &Computational Biology, Indian Institute of Technology, New Delhi-110 016, India.|Kusuma School of Biological Sciences, Indian Institute of Technology, New Delhi-110 016, India.
authors.forename: B
authors.initials: B
authors.lastname: Jayaram
authors.affiliation: Department of Chemistry, University of Delhi, Delhi-110 007, India.
authors.forename: Venkatesu
authors.initials: V
authors.lastname: Pannuru
mesh_terms: D000817:Anilino Naphthalenesulfonates / Q000737:chemistry; D001963:Bromelains / Q000737:chemistry; D020134:Catalytic Domain; D002942:Circular Dichroism; D004795:Enzyme Stability; D006860:Hydrogen Bonding; D057927:Hydrophobic and Hydrophilic Interactions; D008744:Methylamines / Q000737:chemistry*; D056004:Molecular Dynamics Simulation; D011485:Protein Binding; D000072756:Protein Conformation, alpha-Helical; D058767:Protein Unfolding; D059748:Proteolysis; D017550:Spectroscopy, Fourier Transform Infrared; D013816:Thermodynamics
chemical_list: D000817:Anilino Naphthalenesulfonates; D008744:Methylamines; D001963:Bromelains; C005855:trimethyloxamine