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Research Publications (Applied Sciences)

Permanent URI for this collectionhttp://ir-dev.dut.ac.za/handle/10321/213

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    Design, synthesis, anticancer, antimicrobial activities and molecular docking studies of novel quinoline bearing dihydropyridines
    (Elsevier, 2016) Nkosi, S'busiso Mfan'vele; Anand, Krishnan; Anandakumar, S.; Singh, Sanil; Chuturgoon, Anil A.; Gengan, Robert Moonsamy
    A new series of eight quinoline bearing dihydropyridine derivatives (A1–A8) were synthesized in high yield and in short reaction time by a four component reaction of 2-chloro-3-fomyl quinoline, malononitrile, arylamines and dimethyl acetylenedicarboxylate in the presence of a catalytic amount of triethylamine. The compounds were fully characterized by IR, NMR and GC–MS. These compounds were screened for potential biological activity in an A549 lung cancer cell line and were also evaluated for their antibacterial activities against Pseudomonas aeruginosa ATCC 27853, Escherichia coli ATCC 25922 and Staphylococcus aureus ATCC 29213 whilst their molecular docking properties in an enzymatic system were also determined. Compounds A2, A3, A4 and A8 showed anti-proliferative activity; with A4 having the highest toxicity at 250 μg/mL and A8 has high toxicity at 125, 250 and 500 μg/mL, respectively. Antibacterial results indicated that A4 have significant activity against tested microorganisms at the minimum inhibitory concentration (MIC) values of 32 μg/mL against Pseudomonas aeruginosa and Escherichia coli,and 16μg/mL against Staphylococcus aureus. Docking of A1 with human mdm2 indicated the lowest binding energy (−6.111 Kcal/mol) thereby showing strong affinity of the ligand molecule with the receptor which has been stabilized by strong hydrogen bond interactions in the binding pocket. This confirms that A1 is a better inhibitor for E3 ubiquitin-protein ligase mdm2.
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    Molecular dynamics simulation of chitinase I from Thermomyces lanuginosus SSBP to ensure optimal activity
    (Taylor and Fancis Online, 2016-09-22) Khan, Faez Iqbal; Bisetty, Krishna; Gu, Ke-Ren; Singh, Suren; Permaul, Kugen; Hassan, Md. Imtaiyaz; Wei, Dong-Qing
    The fungal chitinase I obtained from Thermomyces lanuginosus SSBP, a thermophilic deuteromycete, has an optimum growth temperature and pH of 323.15 K and 6.5, respectively. This enzyme plays an important task in the defence mechanism of organisms against chitin-containing parasites by hydrolysing β-1, 4-linkages in chitin. It acts as both anti-fungal and biofouling agents, with some being thermostable and suitable for the industrial applications. Three-dimensional model of chitinase I enzyme was predicted and analysed using various bioinformatics tools. The structure of chitinase I exhibited a well-defined TIM barrel topology with an eight-stranded α/β domain. Structural analysis and folding studies at temperatures ranging from 300 to 375 K using 10 ns molecular dynamics simulations clearly showed the stability of the protein was evenly distributed even at higher temperatures, in accordance with the experimental results. We also carried out a number of 20 ns constant pH molecular dynamics simulations of chitinase I at a pH range 2–6 in a solvent. This work was aimed at establishing the optimum activity and stability profiles of chitinase I. We observed a strong conformational pH dependence of chitinase I and the enzyme retained their characteristic TIM barrel topology at low pH.
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    Thermostable chitinase II from Thermomyces lanuginosus SSBP: Cloning, structure prediction and molecular dynamics simulations
    (Elsevier, 2015) Khan, Faez Iqbal; Govender, Algasan; Permaul, Kugen; Singh, Suren; Bisetty, Krishna
    Thermomyces lanuginosus is a thermophilic fungus that produces large number of industrially-significant enzymes owing to their inherent stability at high temperatures and wide range of pH optima, including thermostable chitinases that have not been fully characterized. Here, we report cloning, characterization and structure prediction of a gene encoding thermostable chitinase II. Sequence analysis revealed that chitinase II gene encodes a 343 amino acid protein of molecular weight 36.65 kDa. Our study reports thatchitinase II exhibits a well-defined TIM-barrel topology with an eight-stranded α/β domain. Structural analysis and molecular docking studies suggested that Glu176 is essential for enzyme activity. Folding studies of chitinase II using molecular dynamics simulations clearly demonstrated that the stability of the protein was evenly distributed at 350 K.
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    Thermostable chitinase II from Thermomyces lanuginosus SSBP : Cloning, structure prediction and molecular dynamics simulations
    (Elsevier, 2015-04-08) Khan, Faez Iqbal; Govender, Algasan; Permaul, Kugen; Singh, Suren; Bisetty, Krishna
    Thermomyces lanuginosus is a thermophilic fungus that produces large number of industrially-significant enzymes owing to their inherent stability at high temperatures and wide range of pH optima, including thermostable chitinases that have not been fully characterized. Here, we report cloning, characterization and structure prediction of a gene encoding thermostable chitinase II. Sequence analysis revealed that chitinase II gene encodes a 343 amino acid protein of molecular weight 36.65 kDa. Our study reports that chitinase II exhibits a well-defined TIM-barrel topology with an eight-stranded α/β domain. Structural analysis and molecular docking studies suggested that Glu176 is essential for enzyme activity. Folding studies of chitinase II using molecular dynamics simulations clearly demonstrated that the stability of the protein was evenly distributed at 350 K.