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Dive into the research topics where Animesh Patra is active.

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Featured researches published by Animesh Patra.


Physical Chemistry Chemical Physics | 2014

The influence of charge on the structure and dynamics of water encapsulated in reverse micelles

Animesh Patra; Trung Quan Luong; Rajib Kumar Mitra; Martina Havenith

Hydrogen-bonded structure and relaxation dynamics of water entrapped inside reverse micelles (RMs) composed of surfactants with different charged head groups: sodium bis(2-ethylhexyl) sulfosuccinate (AOT) (anionic), didodecyldimethylammonium bromide (DDAB) (cationic) and Igepal CO-520 (Igepal) (nonionic) in cyclohexane (Cy) have been studied as a function of hydration (defined by ). Sub-diffusive slow (sub-ns) relaxation dynamics of water has been measured by the time resolved fluorescence spectroscopy (TRFS) technique using two fluorophores, namely 8-anilino-1-naphthalenesulfonic acid (ANS) and coumarin-343 (C-343). The hydrogen bonded connectivity network of water confined in these RMs has been investigated by monitoring the hydrogen bond stretching and libration bands of water using far-infrared FTIR spectroscopy. In addition, the ultrafast collective relaxation dynamics of water inside these RMs has been determined by dielectric relaxation in the THz region (0.2-2.0 THz) using THz time domain spectroscopy (THz-TDS). While TRFS measurements establish the retardation of water dynamics for all the RM systems, FTIR and THz-TDS measurements provide with signature of charge specificity.


Journal of Physical Chemistry B | 2013

Do the physical properties of water in mixed reverse micelles follow a synergistic effect: a spectroscopic investigation.

Arindam Das; Animesh Patra; Rajib Kumar Mitra

In this contribution we have tried to investigate whether the mechanical properties of the reverse micellar (RM) interface dictate the physical properties of entrapped water molecules in the RM waterpool. We choose AOT/Igepal-520/cyclohexane (Cy) mixed RM as a model system which exhibits synergistic water solubilization behavior as a function of interfacial stoichiometry. Such a phenomenon associates systematic modification of the interface curvature. Dynamic light scattering (DLS) studies reveal linear increase in the droplet size and aggregation number of the RMs with increasing XIgepal (mole fraction of Igepal in the surfactant mixture). FTIR study in the 3000-3800 cm(-1) region identifies that the relative population of the surface-bound water molecules is higher in AOT RM compared to that in Igepal RM, and in mixed systems it also follows a linear trend with XIgepal. Water relaxation dynamics as probed by time-resolved fluorescence spectroscopy using Coumarin-500 also reveals an overall linear trend with no characteristic feature around the solubilization inflation point. Our study clearly identifies that the physical properties of water in RM are mostly governed by the interfacial stoichiometry and water content, and merely bares any dependence on the mechanical properties of the interface.


Biophysical Chemistry | 2016

Preferential solvation of lysozyme in dimethyl sulfoxide/water binary mixture probed by terahertz spectroscopy

Dipak Kumar Das; Animesh Patra; Rajib Kumar Mitra

We report the changes in the hydration dynamics around a model protein hen egg white lysozyme (HEWL) in water-dimethyl sulfoxide (DMSO) binary mixture using THz time domain spectroscopy (TTDS) technique. DMSO molecules get preferentially solvated at the protein surface, as indicated by circular dichroism (CD) and Fourier transform infrared (FTIR) study in the mid-infrared region, resulting in a conformational change in the protein, which consequently modifies the associated hydration dynamics. As a control we also study the collective hydration dynamics of water-DMSO binary mixture and it is found that it follows a non-ideal behavior owing to the formation of DMSO-water clusters. It is observed that the cooperative dynamics of water at the protein surface does follow the DMSO-mediated conformational modulation of the protein.


Journal of Chemical Physics | 2016

Non-monotonic dynamics of water in its binary mixture with 1,2-dimethoxy ethane: A combined THz spectroscopic and MD simulation study

Debasish Das Mahanta; Animesh Patra; Nirnay Samanta; Trung Quan Luong; Biswaroop Mukherjee; Rajib Kumar Mitra

A combined experimental (mid- and far-infrared FTIR spectroscopy and THz time domain spectroscopy (TTDS) (0.3-1.6 THz)) and molecular dynamics (MD) simulation technique are used to understand the evolution of the structure and dynamics of water in its binary mixture with 1,2-dimethoxy ethane (DME) over the entire concentration range. The cooperative hydrogen bond dynamics of water obtained from Debye relaxation of TTDS data reveals a non-monotonous behaviour in which the collective dynamics is much faster in the low Xw region (where Xw is the mole fraction of water in the mixture), whereas in Xw ∼ 0.8 region, the dynamics gets slower than that of pure water. The concentration dependence of the reorientation times of water, calculated from the MD simulations, also captures this non-monotonous character. The MD simulation trajectories reveal presence of large amplitude angular jumps, which dominate the orientational relaxation. We rationalize the non-monotonous, concentration dependent orientational dynamics by identifying two different physical mechanisms which operate at high and low water concentration regimes.


International Journal of Biological Macromolecules | 2018

Soft interaction and excluded volume effect compete as polyethylene glycols modulate enzyme activity

Nirnay Samanta; Debasish Das Mahanta; Animesh Patra; Rajib Kumar Mitra

Polyethylene glycols (PEGs) can either preferentially bind to biomolecules or exert excluded volume effect depending upon their chain length and concentration. We have studied the effect of ethylene glycol (EG) and PEGs of different chain lengths (Mn 400 and 4000) on the enzyme efficiency of hen-egg-white lysozyme (HEWL) on Micrococcus lysodeikticus (M. Lys.) cell. The activity shows a bell-like profile as the turnover number increases from ~1.3 × 105 s-1 M-1 in water to ~1.7 × 105 s-1 M-1 in presence of 2% PEG-400 beyond which it decreases to ~0.7 × 105 s-1 M-1 at 20% PEG-400. Solvent polarity, excluded volume effect, soft nonspecific interactions and structural flexibility are found to be the competing factors which govern the overall enzyme activity as evidenced from circular dichroism (CD) and fluorescence measurements. Thermal unfolding temperature (Tm) of HEWL also shows a bell-shaped profile with PEG concentration which establishes possible correlation with its activity. We also observe a minimum in the activation energy barrier for the catalysis at low osmolyte concentrations. The maximum in the enzyme efficiency has been explained on the basis of an optimization between excluded volume effect and soft interaction among the protein and the cosolutes.


Chemical Physics Letters | 2013

Dielectric relaxation of the extended hydration sheathe of DNA in the THz frequency region

Debanjan Polley; Animesh Patra; Rajib Kumar Mitra


Journal of Physical Chemistry B | 2012

Slow Relaxation Dynamics of Water in Hydroxypropyl Cellulose-Water Mixture Traces Its Phase Transition Pathway: A Spectroscopic Investigation

Animesh Patra; Pramod Kumar Verma; Rajib Kumar Mitra


Journal of Physical Chemistry B | 2014

Entropy contribution toward micelle-driven deintercalation of drug-DNA complex.

Animesh Patra; Soumitra Hazra; Gopinatha Suresh Kumar; Rajib Kumar Mitra


Physical Chemistry Chemical Physics | 2013

Solvent dynamics in a reverse micellar water-pool: a spectroscopic investigation of DDAB–cyclohexane–water systems

Animesh Patra; Trung Quan Luong; Rajib Kumar Mitra; Martina Havenith


Journal of Physical Chemistry B | 2017

Enhanced Catalytic Activity of α-Chymotrypsin in Cationic Surfactant Solutions: The Component Specificity Revisited

Animesh Patra; Nirnay Samanta; Dipak Kumar Das; Rajib Kumar Mitra

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Rajib Kumar Mitra

S.N. Bose National Centre for Basic Sciences

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Nirnay Samanta

S.N. Bose National Centre for Basic Sciences

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Debanjan Polley

S.N. Bose National Centre for Basic Sciences

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Debasish Das Mahanta

S.N. Bose National Centre for Basic Sciences

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Anjan Barman

S.N. Bose National Centre for Basic Sciences

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Biswaroop Mukherjee

S.N. Bose National Centre for Basic Sciences

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Dipak Kumar Das

S.N. Bose National Centre for Basic Sciences

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Gopinatha Suresh Kumar

Indian Institute of Chemical Biology

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Soumitra Hazra

Indian Institute of Chemical Biology

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