@article {505, title = {Deciphering Mode of Action of Functionally Important Regions in the Intrinsically Disordered Paxillin (Residues 1-313) Using Its Interaction with FAT (Focal Adhesion Targeting Domain of Focal Adhesion Kinase). [Protein Technology Core]}, journal = {PLoS One}, volume = {11}, year = {2016}, month = {2016}, pages = {e0150153}, abstract = {

Intrinsically disordered proteins (IDPs) play a major role in various cellular functions ranging from transcription to cell migration. Mutations/modifications in such IDPs are shown to be associated with various diseases. Current strategies to study the mode of action and regulatory mechanisms of disordered proteins at the structural level are time consuming and challenging. Therefore, using simple and swift strategies for identifying functionally important regions in unstructured segments and understanding their underlying mechanisms is critical for many applications. Here we propose a simple strategy that employs dissection of human paxillin (residues 1-313) that comprises intrinsically disordered regions, followed by its interaction study using FAT (Focal adhesion targeting domain of focal adhesion kinase) as its binding partner to retrace structural behavior. Our findings show that the paxillin interaction with FAT exhibits a masking and unmasking effect by a putative intra-molecular regulatory region. This phenomenon suggests how cancer associated mutations in paxillin affect its interactions with Focal Adhesion Kinase (FAK). The strategy could be used to decipher the mode of regulations and identify functionally relevant constructs for other studies.

}, keywords = {Focal Adhesion Protein-Tyrosine Kinases, Focal Adhesions, Humans, Intrinsically Disordered Proteins, Models, Molecular, Paxillin, Peptide Fragments, Protein Binding, Protein Structure, Tertiary}, issn = {1932-6203}, doi = {10.1371/journal.pone.0150153}, author = {Neerathilingam, Muniasamy and Bairy, Sneha G and Mysore, Sumukh} } @article {506, title = {Simple Detection Methods for Antinutritive Factor β-ODAP Present in Lathyrus sativus L. by High Pressure Liquid Chromatography and Thin Layer Chromatography. [Protein Technology Core]}, journal = {PLoS One}, volume = {10}, year = {2015}, month = {2015}, pages = {e0140649}, abstract = {

Lathyrus sativus L. (Grass pea) is the source for cheap and nutritious food choice in drought and famine susceptible zones in greater part of North India and Africa. The non-protein amino acid β-N-oxalyl-L-α,β-diaminopropionic acid (β-ODAP) has been known for decades for its potent neurotoxic effect, causing irreversible neurodegenerative disease "neurolathyrism", present in both seed and leaf of Lathyrus sativus L. and other species in varying proportions. It is crucial to establish a rapid as well as reliable detection methodology for β-ODAP content in various Lathyrus plants. Currently available HPLC based methods involve multi-step derivatization of the sample. To overcome this, we have developed β-ODAP analysis method by HPLC without any prior derivatization. This method is statistically significant in the range of 2 to 100μg/ml and exhibited linear response with r2 \> 0.99. Limit of detection and quantitation of the later method was determined to be 5.56 μg/ml and 16.86 μg/ml, respectively. In addition to this, a TLC based method has also been developed. The limit of detection of β-ODAP is 0.6μg and for its substrate, L-1,2-diaminopropionic acid is 5μg. Both HPLC and TLC methods were validated by conducting in-vitro bioconversion test to detect the presence of biocatalyst in plant extract. This method is economical, rapid and simple.

}, keywords = {Africa, Amino Acids, Diamino, Chromatography, High Pressure Liquid, Chromatography, Thin Layer, India, Lathyrus, Neurotoxins, Plant Extracts, Plant Leaves, Seeds}, issn = {1932-6203}, doi = {10.1371/journal.pone.0140649}, author = {Ghosh, Bidisha and Mitra, Joy and Chakraborty, Saikat and Bhattacharyya, Jagannath and Chakraborty, Anirban and Sen, Soumitra Kumar and Neerathilingam, Muniasamy} } @article {507, title = {Tailor-made ezrin actin binding domain to probe its interaction with actin in-vitro. [Protein Technology Core]}, journal = {PLoS One}, volume = {10}, year = {2015}, month = {2015}, pages = {e0123428}, abstract = {

Ezrin, a member of the ERM (Ezrin/Radixin/Moesin) protein family, is an Actin-plasma membrane linker protein mediating cellular integrity and function. In-vivo study of such interactions is a complex task due to the presence of a large number of endogenous binding partners for both Ezrin and Actin. Further, C-terminal actin binding capacity of the full length Ezrin is naturally shielded by its N-terminal, and only rendered active in the presence of Phosphatidylinositol bisphosphate (PIP2) or phosphorylation at the C-terminal threonine. Here, we demonstrate a strategy for the design, expression and purification of constructs, combining the Ezrin C-terminal actin binding domain, with functional elements such as fusion tags and fluorescence tags to facilitate purification and fluorescence microscopy based studies. For the first time, internal His tag was employed for purification of Ezrin actin binding domain based on in-silico modeling. The functionality (Ezrin-actin interaction) of these constructs was successfully demonstrated by using Total Internal Reflection Fluorescence Microscopy. This design can be extended to other members of the ERM family as well.

}, keywords = {Actins, Animals, Avian Proteins, Chickens, Cytoskeletal Proteins, In Vitro Techniques, Microfilament Proteins, Models, Molecular, Protein Interaction Domains and Motifs, Recombinant Fusion Proteins}, issn = {1932-6203}, doi = {10.1371/journal.pone.0123428}, author = {Shrivastava, Rohini and K{\"o}ster, Darius and Kalme, Sheetal and Mayor, Satyajit and Neerathilingam, Muniasamy} } @article {508, title = {Soni-removal of nucleic acids from inclusion bodies. [Protein Technology Core]}, journal = {Biochem Biophys Res Commun}, volume = {448}, year = {2014}, month = {2014 May 23}, pages = {45-9}, abstract = {

Inclusion bodies (IBs) are commonly formed in Escherichia coli due to over expression of recombinant proteins in non-native state. Isolation, denaturation and refolding of these IBs is generally performed to obtain functional protein. However, during this process IBs tend to form non-specific interactions with sheared nucleic acids from the genome, thus getting carried over into downstream processes. This may hinder the refolding of IBs into their native state. To circumvent this, we demonstrate a methodology termed soni-removal which involves disruption of nucleic acid-inclusion body interaction using sonication; followed by solvent based separation. As opposed to conventional techniques that use enzymes and column-based separations, soni-removal is a cost effective alternative for complete elimination of buried and/or strongly bound short nucleic acid contaminants from IBs.

}, keywords = {Antigens, CD44, Cell Fractionation, Dengue Virus, Inclusion Bodies, Nucleic Acids, Protein Denaturation, Protein Folding, Recombinant Proteins, Solubility, Sonication, Viral Envelope Proteins}, issn = {1090-2104}, doi = {10.1016/j.bbrc.2014.04.049}, author = {Neerathilingam, Muniasamy and Mysore, Sumukh and Gandham, Sai Hari A} } @article {504, title = {Thioaptamers targeting dengue virus type-2 envelope protein domain III. [Protein Technology Core]}, journal = {Biochem Biophys Res Commun}, volume = {453}, year = {2014}, month = {2014 Oct 24}, pages = {309-15}, abstract = {

Thioaptamers targeting the dengue-2 virus (DENV-2) envelope protein domain III (EDIII) were developed. EDIII, which contains epitopes for binding neutralizing antibodies, is the putative host-receptor binding domain and is thus an attractive target for development of vaccines, anti-viral therapeutic and diagnostic agents. Thioaptamer DENTA-1 bound to DENV-2 EDIII adjacent to a known neutralizing antibody binding site with a dissociation constant of 154nM.

}, keywords = {Antibodies, Neutralizing, Antiviral Agents, Aptamers, Nucleotide, Base Sequence, Dengue Virus, Magnetic Resonance Spectroscopy, Viral Envelope Proteins}, issn = {1090-2104}, doi = {10.1016/j.bbrc.2014.09.053}, author = {Gandham, Sai Hari A and Volk, David E and Lokesh, Ganesh L R and Neerathilingam, Muniasamy and Gorenstein, David G} } @article {1009, title = {Tender coconut water an economical growth medium for the production of recombinant proteins in Escherichia coli. [Protein Technology Facility]}, journal = {BMC Biotechnol}, volume = {13}, year = {2013}, month = {2013 Sep 02}, pages = {70}, abstract = {

BACKGROUND: Escherichia coli is most widely used prokaryotic expression system for the production of recombinant proteins. Several strategies have been employed for expressing recombinant proteins in E.coli. This includes the development of novel host systems, expression vectors and cost effective media. In this study, we exploit tender coconut water (TCW) as a natural and cheaper growth medium for E.coli and Pichia pastoris.

RESULT: E.coli and P.pastoris were cultivated in TCW and the growth rate was monitored by measuring optical density at 600 nm (OD(600nm)), where 1.55 for E.coli and 8.7 for P.pastoris was obtained after 12 and 60 hours, respectively. However, variation in growth rate was observed among TCW when collected from different localities (0.15-2.5 at OD(600nm)), which is attributed to the varying chemical profile among samples. In this regard, we attempted the supplementation of TCW with different carbon and nitrogen sources to attain consistency in growth rate. Here, supplementation of TCW with 25 mM ammonium sulphate (TCW-S) was noted efficient for the normalization of inconsistency, which further increased the biomass of E.coli by 2 to 10 folds, and 1.5 to 2 fold in P.pastoris. These results indicate that nitrogen source is the major limiting factor for growth. This was supported by total nitrogen and carbon estimation where, nitrogen varies from 20 to 60 mg/100 ml while carbohydrates showed no considerable variation (2.32 to 3.96 g/100 ml). In this study, we also employed TCW as an expression media for recombinant proteins by demonstrating successful expression of maltose binding protein (MBP), MBP-TEV protease fusion and a photo switchable fluorescent protein (mEos2) using TCW and the expression level was found to be equivalent to Luria Broth (LB).

CONCLUSION: This study highlights the possible application of TCW-S as a media for cultivation of a variety of microorganisms and recombinant protein expression.

}, keywords = {Ammonium Sulfate, Biomass, Carbohydrates, Carbon, Cocos, Culture Media, Escherichia coli, Gene Expression, Nitrogen, Pichia, Recombinant Proteins}, issn = {1472-6750}, doi = {10.1186/1472-6750-13-70}, author = {Sekar, Narendrakumar and Veetil, Soumya Kariyadan and Neerathilingam, Muniasamy} }