scholarly journals TKSA-MC: A Web Server for rational mutation through the optimization of protein charge interactions

2017 ◽  
Author(s):  
Vinícius G. Contessoto ◽  
Vinícius M. de Oliveira ◽  
Bruno R. Fernandes ◽  
Gabriel G. Slade ◽  
Vitor B. P. Leite
Keyword(s):  
Web Server ◽  
Side Chain ◽  
Positive Energy ◽  
State University ◽  
Native State ◽  
Protein Charge ◽  
The Monte Carlo Method ◽  
Free Energy Contribution ◽  
Thermal Stability Of ◽  
Charge Interactions

AbstractThe TKSAMC is a web server which calculates protein charge-charge interactions via the Tanford-Kirkwood Surface Accessibility model with the Monte Carlo method for sampling different protein protonation states. The optimization of charge-charge interactions via directed mutations has successfully enhanced the thermal stability of different proteins and could be a key to protein engineering improvement. The server presents the electrostatic free energy contribution of each polar-charged residue to protein native state stability. The server also indicates which residues contribute to destabilizing the protein native state with positive energy and the side chain exposed to solvent. This residue is a candidate for mutation to increase protein thermostability as a function of the chosen pH condition. The web server is freely available at UNESP (São Paulo State University - DF/IBILCE): http://tksamc.df.ibilce.unesp.br.

scholarly journals TKSA-MC: A web server for rational mutation through the optimization of protein charge interactions

2018 ◽  
Vol 86 (11) ◽  
pp. 1184-1188 ◽  
Author(s):  
Vinícius G. Contessoto ◽  
Vinícius M. de Oliveira ◽  
Bruno R. Fernandes ◽  
Gabriel G. Slade ◽  
Vitor B. P. Leite
Keyword(s):  
Web Server ◽  
Protein Charge ◽  
Charge Interactions

scholarly journals The ‘Relevant’ Stability of Proteins with Equilibrium Intermediates

2002 ◽  
Vol 2 ◽  
pp. 1209-1215 ◽  
Author(s):  
Javier Sancho ◽  
Marta Bueno ◽  
Luis A. Campos ◽  
Juan Fernandez-Recio ◽  
Maria Pilar Iran ◽  
...  
Keyword(s):  
Side Chain ◽  
Practical Issue ◽  
Single Chain ◽  
Native Conformation ◽  
Native State ◽  
Protein Activity ◽  
Overall Stability ◽  
Protein Stabilisation

Proteins perform many useful molecular tasks, and their biotechnological use continues to increase. As protein activity requires a stable native conformation, protein stabilisation is a major scientific and practical issue. Towards that end, many successful protein stabilisation strategies have been devised in recent years. In most cases, model proteins with a two-state folding equilibrium have been used to study and demonstrate protein stabilisation. Many proteins, however, display more complex folding equilibria where stable intermediates accumulate. Stabilising these proteins requires specifically stabilising the native state relative to the intermediates, as these are expected to lack activity. Here we discuss how to investigate the ‘relevant’ stability of proteins with equilibrium intermediates and propose a way to dissect the contribution of side chain interactions to the overall stability into the ‘relevant’ and ‘nonrelevant’ terms. Examples of this analysis performed on apoflavodoxin and in a single-chain mini antibody are presented.

Modification of styrene polymer by attaching suitable groups as side chain

e-Polymers ◽  
2009 ◽  
Vol 9 (1) ◽  
Author(s):  
Mehrdad Mahkam ◽  
Bakhshali Massoumi ◽  
Hossien Mirfatahi
Keyword(s):  
Thermogravimetric Analysis ◽  
Cycloaddition Reaction ◽  
Side Chain ◽  
H Nmr ◽  
Azide Ion ◽  
Ft Ir ◽  
Commercial Polymers ◽  
Polymerization Method ◽  
Thermal Stability Of ◽  
Dimethyl Acetylene Dicarboxylate

AbstractChemical modification of inexpensive commercial polymers, such as styrene, is a safe methodology to obtain new copolymers. The 4-chloromethyl styrene (CMS) was copolymerized with styrene (in various mole ratios) by free radical polymerization method at 70 ºC using α,α-azobis(isobutyronitrile) (AIBN) as an initiator. The azide ion was covalently attached to the obtained copolymers with replacement of all the chlorine atoms in CMS units. The 1,3-dipolar click cycloaddition reaction between azido polymers and dimethyl acetylene dicarboxylate (DMAD) yielded polymers with 1,2,3-triazoles in side chain. The polymers, obtained in quantitative yields, were characterized by FT-IR and 1H NMR spectroscopy; thermogravimetric analysis (TGA) and GPC studies. The thermogravimetric analysis (TGA) indicated that the thermal stability of copolymers increases with incorporation of 1,2,3-triazole groups in side chains of copolymers.

Side-Chain Engineering for Enhancing the Thermal Stability of Polymer Solar Cells

2015 ◽  
Vol 27 (43) ◽  
pp. 6999-7003 ◽  
Author(s):  
Zidong Li ◽  
Fan Wu ◽  
Hongying Lv ◽  
Dalei Yang ◽  
Zhaobin Chen ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Solar Cells ◽  
Polymer Solar Cells ◽  
Side Chain ◽  
Thermal Stability Of

Improved thermal stability of bulk heterojunctions based on side-chain functionalized poly(3-alkylthiophene) copolymers and PCBM

2013 ◽  
Vol 110 ◽  
pp. 69-76 ◽  
Author(s):  
Sabine Bertho ◽  
Bert Campo ◽  
Fortunato Piersimoni ◽  
Donato Spoltore ◽  
Jan D'Haen ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Side Chain ◽  
Bulk Heterojunctions ◽  
Thermal Stability Of

Modification of polyurethane with novel blocking agent

2014 ◽  
Vol 43 (2) ◽  
pp. 97-103
Author(s):  
Lijun Chen ◽  
Wei Jiang
Keyword(s):  
Blocking Agent ◽  
Side Chain ◽  
The Novel ◽  
Hydrophobic Property ◽  
Monohydric Alcohol ◽  
Content Type ◽  
Fluorinated Polyurethane ◽  
Alcoholysis Reaction ◽  
Chain Extenders ◽  
Thermal Stability Of

Purpose – Fluorinated polyurethane combines some virtues of polyurethane and fluorinated polymer, such as low water absorption, attractive surface properties, good wearability and high weatherability. Fluorocarbon chains have been incorporated into polyurethanes by fluorinated diisocyanates, chain extenders, polyether glycols, polyester glycols and end-cappers. However, the fluorinated polyurethane, which is prepared with monohydric fluorocarbon alcohol, is seldom reported. The purpose of this research is to prepare and apply the novel fluorocarbon alcohols with side chain to modify polyurethane as the blocking agent. Design/methodology/approach – The novel fluorocarbon alcohol with side chain 2-methoxy-3-nonene perfluorinated oxygen propanol (MNPOP) can be prepared via alcoholysis reaction of methanol and 2,3-epoxypropyl perfluorinated nonene ether (EPPNE), which was prepared with etherification of hexafluoropropene trimer (HFPT) and 2,3-glycidol. Structures of EPPNE and MNPOP are confirmed with FTIR and NMR. The polyurethane can be modified when MNPOP is used as blocking agent. Findings – In comparison with the conventional polyurethane, the hydrophobic property of fluorinated polyurethane is improved. However, the increase of tensile strength of modified polyurethane is not obvious because MNPOP belongs to monohydric alcohol. And the function of MNPOP in the modified polyurethane is the blocking agent. The thermal stability of conventional and modified polyurethane is almost the same because MNPOP is de-blocked and fluorocarbon chains have not been incorporated into polyurethanes when the temperature is more than 150°C. Originality/value – The polyurethane is modified with the novel fluorocarbon alcohols with side chain, which functions as the blocking agent. The hydrophobic property of fluorinated polyurethane is improved.

Second Order Nonlinear Optical Properties of Multifunctional Chiral Azobenzene Polymers

e-Polymers ◽  
2008 ◽  
Vol 8 (1) ◽  
Author(s):  
Luigi Angiolini ◽  
Tiziana Benelli ◽  
Renato Bozio ◽  
Matteo Cozzuol ◽  
Loris Giorgini ◽  
...  
Keyword(s):  
Main Chain ◽  
Second Harmonic ◽  
Optically Active ◽  
Polymeric Films ◽  
Side Chain ◽  
Nlo Properties ◽  
Azobenzene Moiety ◽  
Corona Poling ◽  
Thermal Stability Of

AbstractCorona poling behaviours of optically active photochromic copolymers derived from methyl methacrylate (MMA) and the methacrylic ester of (S)-3- hydroxy pyrrolidine linked through the nitrogen atom to the highly conjugated photochromic 4'-(β-cyano-β-(methylsulfonyl)vinyl)-4-azobenzene moiety, have been investigated with the aim to evaluate the effect on the non-linear optical (NLO) properties originated by the presence of inactive side-chain MMA groups along the main chain. The NLO properties of in situ corona poled polymeric films have been studied by second harmonic generation (SHG) measurements. The d33 values of the investigated polymers were determined to be in the range 10-86 pm/V after corona poling. The temporal and thermal stability of the optimal SHG signals obtained after corona poling process of all the macromolecular materials has been investigated and compared. The results indicate that the maximum of these properties can be obtained at a molar content of photochromic units around 20- 40%.

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