@article { ISI:000362964900007,
	title = {Sequence and structure-based comparative analysis to assess, identify and improve the thermostability of penicillin G acylases},
	journal = {Journal of Industrial Microbiology \& Biotechnology},
	volume = {42},
	number = {11},
	year = {2015},
	month = {NOV},
	pages = {1493-1506},
	publisher = {SPRINGER HEIDELBERG},
	address = {TIERGARTENSTRASSE 17, D-69121 HEIDELBERG, GERMANY},
	abstract = {<p>Penicillin acylases are enzymes employed by the pharmaceutical industry for the manufacture of semi-synthetic penicillins. There is a continuous demand for thermostable and alkalophilic enzymes in such applications. We have carried out a computational analysis of known penicillin G acylases (PGAs) in terms of their thermostable nature using various protein-stabilizing factors. While the presence of disulfide bridges was considered initially to screen putative thermostable PGAs from the database, various other factors such as high arginine to lysine ratio, less content of thermolabile amino acids, presence of proline in beta-turns, more number of ion-pair and other non-bonded interactions were also considered for comparison. A modified consensus approach designed could further identify stabilizing residue positions by site-specific comparison between mesostable and thermostable PGAs. A most likely thermostable enzyme identified from the analysis was PGA from Paracoccus denitrificans (PdPGA). This was cloned, expressed and tested for its thermostable nature using biochemical and biophysical experiments. The consensus site-specific sequence-based approach predicted PdPGA to be more thermostable than Escherichia coli PGA, but not as thermostable as the PGA from Achromobacter xylosoxidans. Experimental data showed that PdPGA was comparatively less thermostable than Achromobacter xylosoxidans PGA, although thermostability factors favored a much higher stability. Despite being mesostable, PdPGA being active and stable at alkaline pH is an advantage. Finally, several residue positions could be identified in PdPGA, which upon mutation selectively could improve the thermostability of the enzyme.</p>},
	keywords = {Alkalistable, beta-lactam antibiotics, Consensus approach, Disulfide bridge, Ion pairs, Penicillin acylase, Thermostability},
	issn = {1367-5435},
	doi = {10.1007/s10295-015-1690-x},
	author = {Panigrahi, Priyabrata and Chand, Deepak and Mukherji, Ruchira and Ramasamy, Sureshkumar and Suresh, C. G.}
}
@article { ISI:000373738200010,
	title = {Comparative investigation of the ionicity of aprotic and protic ionic liquids in molecular solvents by using conductometry and NMR spectroscopy},
	journal = {Chemphyschem},
	volume = {17},
	number = {7},
	year = {2016},
	month = {APR},
	pages = {1006-1017},
	publisher = {WILEY-V C H VERLAG GMBH},
	address = {POSTFACH 101161, 69451 WEINHEIM, GERMANY},
	abstract = {<p>Electrical conductivity (sigma), viscosity (), and self-diffusion coefficient (D) measurements of binary mixtures of aprotic and protic imidazolium-based ionic liquids with water, dimethyl sulfoxide, and ethylene glycol were measured from 293.15 to 323.15K. The temperature dependence study reveals typical Arrhenius behavior. The ionicities of aprotic ionic liquids were observed to be higher than those of protic ionic liquids in these solvents. The aprotic ionic liquid, 1-butyl-3-methylimidazolium tetrafluoroborate, [bmIm][BF4], displays 100\% ionicity in both water and ethylene glycol. The protic ionic liquids in both water and ethylene glycol are classed as good ionic candidates, whereas in DMSO they are classed as having a poor ionic nature. The solvation dynamics of the ionic species of the ionic liquids are illustrated on the basis of the (HNMR)-H-1 chemical shifts of the ionic liquids. The self-diffusion coefficients D of the cation and anion of [HmIm][CH3COO] in D2O and in [D-6]DMSO are determined by using H-1 nuclei with pulsed field gradient spin-echo NMR spectroscopy.</p>},
	keywords = {conducting materials, Electrochemistry, electrostatic interactions, Ion pairs, ionic liquids},
	issn = {1439-4235},
	doi = {10.1002/cphc.201501156},
	author = {Thawarkar, Sachin and Khupse, Nageshwar D. and Kumar, Anil}
}
