Characterization of differentially regulated carboxypeptidase (metallopeptidase M32) protein in Miltefosine resistant Leishmania donovani parasites.

Introduction: Carboxypeptidase, a member of the metallopeptidase M32 family, catalyses the C-terminal hydrolysis of a variety of peptides and proteins in the presence of metal ions.

Objective: To characterize Leishmania donovani carboxypeptidase (LdCP) in miltefosine (MIL) drug-resistant parasites.

Methods: We performed the MTT assay and cell cycle analysis to confirm the MIL resistance of clinical isolates.

Structure and Characterization of Catanionic Complexes and Biocompatible Vesicles of -Acyltaurine and Sarcosine Alkyl Ester: Encapsulation and Release Studies with 5-Fluorouracil.

Hydrated dispersions containing equimolar mixtures of cationic and anionic amphiphiles, referred to as catanionic systems, exhibit synergistic physicochemical properties, and mixing single-chain cationic and anionic lipids can lead to the spontaneous formation of vesicles as well as other phase structures. In the present work, we have characterized two catanionic systems prepared by mixing -acyltaurines (NATs) and sarcosine alkyl esters (SAEs) bearing 11 and 12 C atoms in the acyl/alkyl chains. Turbidimetric and isothermal titration calorimetric studies revealed that both NATs form equimolar complexes with SAEs having matching acyl/alkyl chains.

Galactose Glycopolymer- Silica Nanoparticles: Synthesis and Binding Studies with Lectin.

Weak binding of carbohydrates with protein receptors possesses serious drawbacks in the advancement of therapeutics; however, the development of strategies for multipoint interactions between carbohydrates and protein can overcome these challenges. One such method is developed in this work where glycopolymer- silica nanoparticles with a large number of carbohydrate units are prepared for the interactions with multiple binding sites of the protein. First, a glycomonomer, β-d-galactose-hydroxyethyl methacrylate (β-GEMA), was synthesized in a two-step process by coupling β-d-galactose pentaacetate and hydroxyethyl methacrylate (HEMA), followed by deacetylation for the preparation of poly(β-GEMA) glycopolymers (GPs).

Inhibition of human DNA alkylation damage repair enzyme ALKBH2 by HIV protease inhibitor ritonavir.

The human DNA repair enzyme AlkB homologue-2 (ALKBH2) repairs methyl adducts from genomic DNA and is overexpressed in several cancers. However, there are no known inhibitors available for this crucial DNA repair enzyme. The aim of this study was to examine whether the first-generation HIV protease inhibitors having strong anti-cancer activity can be repurposed as inhibitors of ALKBH2.

Structure, Self-Assembly, and Phase Behavior of Neuroactive -Acyl GABAs: Doxorubicin Encapsulation in NPGABA/DPPC Liposomes and Release Studies.

N-Acylated amino acids and neurotransmitters in mammals exert significant biological effects on the nervous system, immune responses, and vasculature. -Acyl derivatives of γ-aminobutyric acid (-acyl GABA), which belong to both classes mentioned above, are prominent among them. In this work, a homologous series of -acyl GABAs bearing saturated -acyl chains (C8-C18) have been synthesized and characterized with respect to self-assembly, thermotropic phase behavior, and supramolecular organization.

Effect of temperature and pH on the structure and stability of tumor-specific lectin jacalin and insights into the location of its tryptophan residues: CD, DSC and fluorescence studies.

Jacalin, the jackfruit seed lectin, exhibits high specificity for the tumor-specific T-antigen and is used in various biomedical and biotechnological applications. Here, we report biophysical studies on the thermal unfolding of jacalin and the effect of pH and temperature on its secondary structure. Differential scanning calorimetric (DSC) studies revealed that native jacalin unfolds at ∼60 °C and that carbohydrate binding stabilizes the protein structure.

Contrasting effects of molecular crowding on the membrane-perturbing and chaperone-like activities of major bovine seminal plasma protein, PDC-109.

Crowded environments inside cells and biological fluids greatly affect protein stability and activity. PDC-109, a polydisperse oligomeric protein of the bovine seminal plasma selectively binds choline phospholipids on the sperm cell surface and causes membrane destabilization and lipid efflux, leading to acrosome reaction. PDC-109 also exhibits chaperone-like activity (CLA) and protects client proteins against various kinds of stress, such as high temperature and low pH.

Primary structure determination and physicochemical characterization of DSP-3, a phosphatidylcholine binding glycoprotein of donkey seminal plasma.

Major proteins of the seminal plasma in a variety of mammals such as bovine PDC-109, equine HSP-1/2, and donkey DSP-1 contain fibronectin type-II (FnII) domains and are referred to as FnII family proteins. To further our understanding on these proteins, we carried out detailed studies on DSP-3, another FnII protein of donkey seminal plasma. High-resolution mass-spectrometric studies revealed that DSP-3 contains 106 amino acid residues and is heterogeneously glycosylated with multiple acetylations on the glycans.

Subunit association, and thermal and chemical unfolding of Cucurbitaceae phloem exudate lectins. A review.

Detailed characterization of protein (un)folding intermediates is crucial for understanding the (un)folding pathway, aggregation, stability and their functional properties. In recent years, stress-inducible lectins are being investigated with much interest. In plants phloem proteins PP1 and PP2 are major components of the phloem fluid.

Macromolecular Crowding Significantly Affects the Conformational Features and Carbohydrate Binding Properties of CIA17, a PP2-Type Lectin from .

The effect of macromolecular crowding on the conformational features and carbohydrate binding properties of CIA17, a PP2-type lectin, was investigated employing polymeric dextrans D6, D40, and D70 ( ∼ 6, 40, and 70 kDa, respectively) as crowders. While the secondary structure of CIA17 was significantly affected by D6, with a considerable decrease in the number of β-sheets and β-turns with a corresponding increase in the number of unordered structures, relatively smaller changes were induced by D40 and D70. However, differential scanning calorimetry (DSC) studies revealed that the thermal stability of the protein remains unchanged in the presence of crowders.

Base-triggerable lauryl sarcosinate-dodecyl sulfate catanionic liposomes: structure, biophysical characterization, and drug entrapment/release studies.

Equimolar mixtures of oppositely charged single-chain amphiphiles form a variety of phases, including vesicles. Such catanionic mixed lipid systems show high stability and exhibit versatile physicochemical properties. In the present study we have investigated the aggregation behaviour of lauryl sarcosinate hydrochloride (LS·HCl) in aqueous dispersion as well as its interaction with the anionic surfactant sodium dodecyl sulfate (SDS).

Cucurbitaceae phloem exudate lectins: Purification, molecular characterization and carbohydrate binding characteristics.

Much of the plant lectin research was focused on these proteins from seeds, whereas lectins from other plant tissues have been less investigated. Although presence of lectins in the phloem exudate of Cucurbitaceae species was reported over 40 years ago, only a few proteins from this family have been purified and characterized with respect to ligand binding properties, primary and secondary structures, while no 3D structure of a member of this family is known so far. Unlike lectins from other plant families and sources (e.

Low-pH Molten Globule-Like Form of CIA17, a Chitooligosaccharide-Specific Lectin from the Phloem Exudate of , Retains Carbohydrate-Binding Ability.

pH-induced changes in the conformation, structural dynamics, and carbohydrate-binding activity of agglutinin (CIA17), a PP2-type lectin, were investigated employing biophysical approaches. The secondary structure of CIA17 remains nearly unaltered over a wide pH range (2.0-8.

Deciphering the thermotolerance of chitinase O from Chitiniphilus shinanonensis by in vitro and in silico studies.

Biochemical and biophysical studies revealed that chitinase O from Chitiniphilus shinanonensis (CsChiO) exhibits considerable thermotolerance, possibly due to the formation of a stable structural conformation. CsChiO is an exochitinase with a temperature optimum of 70 °C. The secondary structures of CsChiO and its catalytic domain (Cat-CsChiO) are only marginally affected upon heating up to 90 °C, as revealed by circular dichroism (CD) spectroscopy.

Effect of Sorbitol on Alpha-Crystallin Structure and Function.

Loss of eye lens transparency due to cataract is the leading cause of blindness all over the world. While aggregation of lens crystallins is the most common endpoint in various types of cataracts, chaperone-like activity (CLA) of α-crystallin preventing protein aggregation is considered to be important for maintaining the eye lens transparency. Osmotic stress due to increased accumulation of sorbitol under hyperglycemic conditions is believed to be one of the mechanisms for diabetic cataract.

Purification, molecular characterization and ligand binding properties of the major donkey seminal plasma protein DSP-1.

Fibronectin type-II (FnII) family proteins are the major proteins in many mammalian species including bull, horse and pig. In the present study, a major FnII protein has been identified and isolated from donkey (Equus hemionus) seminal plasma, which we refer to as Donkey Seminal Plasma protein-1 (DSP-1). The amino acid sequence determined by mass spectrometry and computational modeling studies revealed that DSP-1 is homologous to other mammalian seminal plasma proteins, including bovine PDC-109 (also known as BSP-A1/A2) and equine HSP-1/2.

Packing polymorphism, odd-even alternation and thermotropic phase transitions in -,-diacylethanolamines with varying -acyl chains. A combined experimental and computational study.

-,-Diacylethanolamines (DAEs) are derived by simple esterification of bioactive -acylethanolamines, which are present in plant and animal tissues. In this study, two homologous series of DAEs, namely -acyl ( = 8-15), -palmitoylethanolamines (N-O16s) and -acyl ( = 8-14), -pentadecanoylethanolamines (N-O15s) were synthesized and characterized with respect to thermotropic phase transitions, crystal structures and intermolecular interactions. In addition, computational studies were performed to get a molecular level insight into the role of different factors in selective polymorphism in N-O16s and N-O15s.

DSC and FCS Studies Reveal the Mechanism of Thermal and Chemical Unfolding of CIA17, a Polydisperse Oligomeric Protein from .

The mechanism of thermal and chemical unfolding of agglutinin (CIA17), a chitooligosacharide-specific phloem exudate lectin, was investigated by biophysical approaches. DSC studies revealed that the unfolding thermogram of CIA17 consists of three components ( ∼ 98, 106, and 109 °C), which could be attributed to the dissociation of protein oligomers into constituent dimers, dissociation of the dimers into monomers, and unfolding of the monomers. Intrinsic fluorescence studies on the chemical denaturation by guanidinium thiocyanate and guanidinium chloride indicated the presence of two distinct steps in the unfolding pathway, which could be assigned to dissociation of the dimeric protein into monomers and unfolding of the monomers.

Structure, thermotropic phase behavior and membrane interaction of N-acyl-β-alaninols. Homologs of stress-combating N-acylethanolamines.

β-Alaninol and its derivatives were reported to exhibit interesting biological and pharmacological activities and showed potential application in formulating drug delivery vehicles. In the present study, we report the synthesis and characterization of N-acyl-β-alaninols (NABAOHs) bearing saturated acyl chains (n = 8-20) with respect to thermotropic phase behavior, supramolecular organization and interaction with diacylphosphatidylcholine, a major membrane lipid. Results obtained from DSC and powder XRD studies revealed that the transition temperatures (T), transition enthalpies (ΔH), transition entropies (ΔS) and d-spacings of NABAOHs show odd-even alteration.

New Class of Chitosanase from for the Generation of Chitooligosaccharides.

Chitooligosaccharides (COS) generated from either chitin (chitin oligosaccharides) or chitosan (chitosan oligosaccharides) have a wide range of applications in agriculture, medicine, and other fields. Here, we report the characterization of a chitosanase from (Csn) and the importance of a tryptophan (Trp), W204, for Csn activity. Csn hydrolyzed the chitosan polymer by an endo mode.

Purification, biochemical/biophysical characterization and chitooligosaccharide binding to BGL24, a new PP2-type phloem exudate lectin from bottle gourd (Lagenaria siceraria).

Phloem Protein 2 (PP2), highly abundant in the sieve elements of plants, plays a significant role in wound sealing and anti-pathogenic responses. In this study, we report the purification and characterization of a new PP2-type lectin, BGL24 from the phloem exudate of bottle gourd (Lagenaria siceraria). BGL24 is a homodimer with a subunit mass of ~24 kDa and exhibits high specificity for chitooligosaccharides.

Purification and biochemical/biophysical characterization of two hexosaminidases from the fresh water mussel, Lamellidens corrianus.

Two thermostable isoforms of a hexosaminidase were purified to homogeneity from the soluble extract of fresh water mussel Lamellidens corrianus, employing a variety of chromatographic techniques. Hexosaminidase A (HexA) is a heterodimer with subunit masses of ~80 and 55 kDa. Hexosaminidase B (HexB) is a homodimer with a subunit mass of 55-60 kDa.

Conserved core tryptophans of FnII domains are crucial for the membranolytic and chaperone-like activities of bovine seminal plasma protein PDC-109.

The fibronectin type II (FnII) domain, present in diverse vertebrate proteins, plays crucial roles in several fundamental biological processes. PDC-109, the major bovine seminal plasma protein, contains two FnII domains that bind to choline phospholipids on sperm plasma membrane and induce lipid efflux crucial for successful fertilization. PDC-109 also exhibits chaperone-like activity and protects other proteins against various types of stress.

Chitooligosaccharide binding to CIA17 (Coccinia indica agglutinin). Thermodynamic characterization and formation of higher order complexes.

CIA17 is a PP2-like, homodimeric lectin made up of 17 kDa subunits present in the phloem exudate of ivy gourd (Coccinia indica). Isothermal titration calorimetric (ITC) studies on the interaction of chitooligosaccharides [(GlcNAc)] showed that the dimeric protein has two sugar binding sites which recognize chitotriose with ~70-fold higher affinity than chitobiose, indicating that the binding site is extended in nature. ITC, atomic force microscopic and non-denaturing gel electrophoresis studies revealed that the high-affinity interaction of CIA17 with chitohexaose (K = 1.

Thermodynamic Analysis of Protein-Lipid Interactions by Isothermal Titration Calorimetry.

Isothermal titration calorimetry is a highly sensitive and powerful technique for the study of molecular interactions. This method can be applied universally for studying the interaction between moleculeAbstracts, molecular assembles and ions as it measures the heat changes resulting from such interactions and does not need any probe molecule/moiety to be incorporated into the system under investigation. This method has been applied quite extensively to investigate the interaction of proteins with other biomolecules such as small ligands, other proteins, nucleic acids, lipid membranes as well as to study the interaction of antibodies, drugs, metal ions and nanoparticles with target proteins or antigens, nucleic acids, and membranes.