Supplementary data for article: Grozdanović, M. M.; Burazer, L. M.; Gavrović-Jankulović, M. Kiwifruit (Actinidia Deliciosa) Extract Shows Potential as a Low-Cost and Efficient Milk-Clotting Agent. International Dairy Journal 2013, 32 (1), 46–52. https://doi.org/10.1016/j.idairyj.2013.03.001

Supplementary material for: [https://doi.org/10.1016/j.idairyj.2013.03.001]Related to published version: [http://cherry.chem.bg.ac.rs/handle/123456789/1589

Supplementary data for article: Grozdanovic, M. M.; Drakulić, B. J.; Gavrović-Jankulović, M. Conformational Mobility of Active and E-64-Inhibited Actinidin. Biochimica et Biophysica Acta: General Subjects 2013, 1830 (10), 4790–4799. https://doi.org/10.1016/j.bbagen.2013.06.015

Supplementary material for: [https://doi.org/10.1016/j.bbagen.2013.06.015]Related to published version: [http://cherry.chem.bg.ac.rs/handle/123456789/1398

Supplementary data for article: Grozdanović, M. M.; Burazer, L. M.; Gavrović-Jankulović, M. Kiwifruit (Actinidia Deliciosa) Extract Shows Potential as a Low-Cost and Efficient Milk-Clotting Agent. International Dairy Journal 2013, 32 (1), 46–52. https://doi.org/10.1016/j.idairyj.2013.03.001

Supplementary material for: [https://doi.org/10.1016/j.idairyj.2013.03.001]Related to published version: [http://cherry.chem.bg.ac.rs/handle/123456789/1589

Structure of the mammalian ribosome as it decodes the selenocysteine UGA codon

The elongation of eukaryotic selenoproteins relies on a poorly understood process of interpreting in-frame UGA stop codons as selenocysteine (Sec). We used cryo-electron microscopy to visualize Sec UGA recoding in mammals. A complex between the noncoding Sec-insertion sequence (SECIS), SECIS-binding protein 2 (SBP2), and 40S ribosomal subunit enables Sec-specific elongation factor eEFSec to deliver Sec. eEFSec and SBP2 do not interact directly but rather deploy their carboxyl-terminal domains to engage with the opposite ends of the SECIS. By using its Lys-rich and carboxyl-terminal segments, the ribosomal protein eS31 simultaneously interacts with Sec-specific transfer RNA (tRNASec) and SBP2, which further stabilizes the assembly. eEFSec is indiscriminate toward l-serine and facilitates its misincorporation at Sec UGA codons. Our results support a fundamentally distinct mechanism of Sec UGA recoding in eukaryotes from that in bacteria

Supplementary data for article: Grozdanovic, M. M.; Drakulić, B. J.; Gavrović-Jankulović, M. Conformational Mobility of Active and E-64-Inhibited Actinidin. Biochimica et Biophysica Acta: General Subjects 2013, 1830 (10), 4790–4799. https://doi.org/10.1016/j.bbagen.2013.06.015

Supplementary material for: [https://doi.org/10.1016/j.bbagen.2013.06.015]Related to published version: [http://cherry.chem.bg.ac.rs/handle/123456789/1398

Conformational mobility of active and E-64-inhibited actinidin

Background: Actinidin, a protease from kiwifruit, belongs to the C1 family of cysteine proteases. Cysteine proteases were found to be involved in many disease states and are valid therapeutic targets. Actinidin has a wide pH activity range and wide substrate specificity, which makes it a good model system for studying enzyme-substrate interactions. Methods: The influence of inhibitor (E-64) binding on the conformation of actinidin was examined by 2D PAGE, circular dichroism (CD) spectroscopy, hydrophobic ligand binding assay, and molecular dynamics simulations. Results: Significant differences were observed in electrophoretic mobility of proteolytically active and E-64-inhibited actinidin. CD spectrometry and hydrophobic ligand binding assay revealed a difference in conformation between active and inhibited actinidin. Molecular dynamics simulations showed that a loop defined by amino-acid residues 88-104 had greater conformational mobility in the inhibited enzyme than in the active one. During MD simulations, the covalently bound inhibitor was found to change its conformation from extended to folded, with the guanidino moiety approaching the carboxylate. Conclusions: Conformational mobility of actinidin changes upon binding of the inhibitor, leading to a sequence of events that enables water and ions to protrude into a newly formed cavity of the inhibited enzyme. Drastic conformational mobility of E-64, a common inhibitor of cysteine proteases found in many crystal structures stored in PDB, was also observed. General significance: The analysis of structural changes which occur upon binding of an inhibitor to a cysteine protease provides a valuable starting point for the future design of therapeutic agents.Supplementary material: [http://cherry.chem.bg.ac.rs/handle/123456789/3476

The effect of kiwifruit (Actinidia deliciosa) cysteine protease actinidin on the occludin tight junction network in T84 intestinal epithelial cells

Actinidin, a kiwifruit cysteine protease, is a marker allergen for genuine sensitization to this food allergen source. Inhalatory cysteine proteases have the capacity for disruption of tight junctions (TJs) enhancing the permeability of the bronchial epithelium. No such properties have been reported for allergenic food proteases so far. The aim was to determine the effect of actinidin on the integrity of T84 monolayers by evaluating its action on the TJ protein occludin. Immunoblot and immunofluorescence were employed for the detection of occludin protein alterations. Gene expression was evaluated by RT-PCR. Breach of occludin network was assessed by measuring transepithelial resistance, blue dextran leakage and passage of allergens from the apical to basolateral compartment. Actinidin exerted direct proteolytic cleavage of occludin; no alteration of occludin gene expression was detected. There was a reduction of occludin staining upon actinidin treatment as a consequence of its degradation and dispersion within the membrane. There was an increase in permeability of the T84 monolayer resulting in reduced transepithelial resistance, blue dextran leakage and passage of allergens actinidin and thaumatin-like protein from the apical to basolateral compartment. Opening of TJs by actinidin may increase intestinal permeability and contribute to the process of sensitization in kiwifruit allergy. (C) 2014 Elsevier Ltd. All rights reserved

Employment of colorimetric enzyme assay for monitoring expression and solubility of GST fusion proteins targeted to inclusion bodies

High levels of recombinant protein expression can lead to the formation of insoluble inclusion bodies. These complex aggregates are commonly solubilized in strong denaturants, such as 6-8 M urea, although, if possible, solubilization under milder conditions could facilitate subsequent refolding and purification of bioactive proteins. Commercially available GST-tag assays are designed for quantitative measurement of GST activity under native conditions. GST fusion proteins accumulated in inclusion bodies are considered to be undetectable by such assays. In this work, solubilization of recombinantly produced proteins was performed in 4 M urea. The activity of rGST was assayed in 2 M urea and it was shown that rGST preserves 85% of its activity under such denaturing conditions. A colorimetric GST activity assay with 1-chloro-2, 4-dinitrobenzene (CDNB) was examined for use in rapid detection of expression targeted to inclusion bodies and for the identification of inclusion body proteins which can be solubilized in low concentrations of chaotropic agents. Applicability of the assay was evaluated by tracking protein expression of two GST-fused allergens of biopharmaceutical value in E. coli, GST-Der p 2 and GST-Mus a 5, both targeted to inclusion bodies