53 research outputs found
Structural And Functional Prediction Of Hypothetical Proteins From Klebsiella Pneumoniae MGH78578: Molecular Modelling Studies
Twenty percent of the genes from Klebsiella pneumonaie MGH78578 coded for hypothetical protein. Two particular hypothetical proteins KPN00728 and KPN00729 were identified using bioinformatics approaches. Both open reading frames showed high sequence homology to succinate dehydrogenase Chain C (SdhC) and D (SdhD) from Escherichia coli KPN00729 was annotated as SdhD in May 2008. Thus, investigation on KPN00728 remained as no annotation for SdhC gene in the complete genome sequence of Klebsiella pneumoniae MGH78578. In this study, KPN00728 has a missing region with conserved residues which is important for
ubiquinone (UQ) and heme group binding. Structure and function prediction of KPN00728 coupled with secondary structure analysis and transmembrane topology showed KPN00728 adopts SDH-(subunit C)-like structure
Structural Modeling and Biochemical Characterization of Recombinant KPN_02809, a Zinc-Dependent Metalloprotease from Klebsiella pneumoniae MGH 78578
Klebsiella pneumoniae is a Gram-negative, cylindrical rod shaped opportunistic pathogen that is found in the environment as well as existing as a normal flora in mammalian mucosal surfaces such as the mouth, skin, and intestines. Clinically it is the most important member of the family of Enterobacteriaceae that causes neonatal sepsis and nosocomial infections. In this work, a combination of protein sequence analysis, structural modeling and molecular docking simulation approaches were employed to provide an understanding of the possible functions and characteristics of a hypothetical protein (KPN_02809) from K. pneumoniae MGH 78578. The computational analyses showed that this protein was a metalloprotease with zinc binding motif, HEXXH. To verify this result, a ypfJ gene which encodes for this hypothetical protein was cloned from K. pneumoniae MGH 78578 and the protein was overexpressed in Escherichia coli BL21 (DE3). The purified protein was about 32 kDa and showed maximum protease activity at 30 °C and pH 8.0. The enzyme activity was inhibited by metalloprotease inhibitors such as EDTA, 1,10-phenanthroline and reducing agent, 1,4-dithiothreitol (DTT). Each molecule of KPN_02809 protein was also shown to bind one zinc ion. Hence, for the first time, we experimentally confirmed that KPN_02809 is an active enzyme with zinc metalloprotease activity
Thioguanine-based DENV-2 NS2B/NS3 protease inhibitors: Virtual screening, synthesis, biological evaluation and molecular modelling
Dengue virus Type 2 (DENV-2) is predominant serotype causing major dengue epidemics. There are a number of studies carried out to find its effective antiviral, however to date, there is still no molecule either from peptide or small molecules released as a drug. The present study aims to identify small molecules inhibitor from National Cancer Institute database through virtual screening. One of the hits, D0713 (IC50 = 62 μM) bearing thioguanine scaffold was derivatised into 21 compounds and evaluated for DENV-2 NS2B/NS3 protease inhibitory activity. Compounds 18 and 21 demonstrated the most potent activity with IC50 of 0.38 μM and 16 μM, respectively. Molecular dynamics and MM/PBSA free energy of binding calculation were conducted to study the interaction mechanism of these compounds with the protease. The free energy of binding of 18 calculated by MM/PBSA is -16.10 kcal/mol compared to the known inhibitor, panduratin A (-11.27 kcal/mol), which corroborates well with the experimental observation. Results from molecular dynamics simulations also showed that both 18 and 21 bind in the active site and stabilised by the formation of hydrogen bonds with Asn174
Antioxidant, Wound Healing Potential and In Silico Assessment of Naringin, Eicosane and Octacosane
1. Diabetic chronic wounds, mainly foot ulcers, constitute one of the most common complications of poorly managed diabetes mellitus. The most typical reasons are insufficient
glycemic management, latent neuropathy, peripheral vascular disease, and neglected foot care. In addition, it is a common cause of foot osteomyelitis and amputation of the lower extremities. Patients are admitted in larger numbers attributable to chronic wounds compared to any other diabetic disease. In the United States, diabetes is currently the most common cause of non-traumatic amputations. Approximately five percent of diabetics develop foot ulcers, and one percent require amputation. Therefore, it is necessary to identify sources of lead with
wound-healing properties. Redox imbalance due to excessive oxidative stress is one of the causes for the development of diabetic wounds. Antioxidants have been shown to decrease the progression of diabetic neuropathy by scavenging ROS, regenerating endogenous and exogenous antioxidants, and reversing redox imbalance. Matrix metalloproteinases (MMPs) play vital roles in numerous phases of the wound healing process. Antioxidant and fibroblast cell migration
activity of Marantodes pumilum (MP) crude extract has previously been reported. Through their antioxidant, epithelialization, collagen synthesis, and fibroblast migration activities, the authors hypothesise that naringin, eicosane and octacosane identified in the MP extract may have wound-healing properties. 2. The present study aims to identify the bioactive components present in the dichloromethane (DCM) extract of M. pumilum and evaluate their antioxidant and wound healing activity. Bioactive components were identified using LCMS, HPTLC and GCMS. Excision wound on STZ-induced diabetic rat model, human dermal fibroblast (HDF) cell line and colorimetric antioxidant assays were used to evaluate wound healing and antioxidant activities, respectively. Molecular docking and pkCMS software would be utilised to predict binding energy and affinity, as well as ADME parameters. 3. Naringin (NAR), eicosane (EIC), and octacosane (OCT) present in MP displayed antioxidant action and wound excision closure.
Histological examination HDF cell line demonstrates epithelialization, collagen production, fibroblast migration, polymorphonuclear leukocyte migration (PNML), and fibroblast movement. The results of molecular docking indicate a substantial attraction and contact between
MMPs. pkCMS prediction indicates inadequate blood-brain barrier permeability, low toxicity, and absence of hepatotoxicity. 4. Wound healing properties of (NEO) naringin, eicosane and octacosane may be the result of their antioxidant properties and possible interactions with MMP
Discovery of Potential M2 Channel Inhibitors Based on the Amantadine Scaffold via Virtual Screening and Pharmacophore Modeling
The M2 channel protein on the influenza A virus membrane has become the main target of the anti-flu drugs amantadine and rimantadine. The structure of the M2 channel proteins of the H3N2 (PDB code 2RLF) and 2009-H1N1 (Genbank accession number GQ385383) viruses may help researchers to solve the drug-resistant problem of these two adamantane-based drugs and develop more powerful new drugs against influenza A virus. In the present study, we searched for new M2 channel inhibitors through a combination of different computational methodologies, including virtual screening with docking and pharmacophore modeling. Virtual screening was performed to calculate the free energies of binding between receptor M2 channel proteins and 200 new designed ligands. After that, pharmacophore analysis was used to identify the important M2 protein-inhibitor interactions and common features of top binding compounds with M2 channel proteins. Finally, the two most potential compounds were determined as novel leads to inhibit M2 channel proteins in both H3N2 and 2009-H1N1 influenza A virus
Active Site Flexibility of Mycobacterium tuberculosis Isocitrate Lyase in Dimer Form
Tuberculosis (TB) still remains a global threat due to the emergence
of a drug-resistant strain. Instead of focusing on the drug target
of active stage TB, we are highlighting the isocitrate lyase (ICL)
at the dormant stage TB. ICL is one of the persistent factors for Mycobacterium tuberculosis (MTB) to survive during
the dormant phase. In addition, the absence of ICL in human has made
ICL a potential drug target for TB therapy. However, the dynamic details
of ICL which could give insights to the ICL–ligand interaction
have yet to be solved. Therefore, a series of ICL dimer dynamics studies
through molecular dynamics simulation were performed in this work.
The ICL active site entrance gate closure is contributed to by hydrogen
bonding and electrostatic interactions with the C-terminal. Analysis
suggested that the open–closed behavior of the ICL active site
entrance depends on the type of ligand present in the active site.
We also observed four residues (Ser91, Asp108, Asp153, and Cys191)
which could possibly be the nucleophiles for nucleophilic attack on
the cleavage of isocitrate at the C<sub>2</sub>–C<sub>3</sub> bond. We hope that the elucidation of ICL dynamics can benefit future
works such as lead identification or antibody design against ICL for
TB therapeutics
Free radical scavenging and cytotoxic properties of acylated and non-acylated kaempferol glycosides from Stenochlaena Palustris: a perspective on their structure – Activity relationships
Flavonoid glycosides that are present in acylated form have good prospect to be developed into therapeutic agents due to their improved biological properties, stability and physico-chemical properties compared to their maternal compounds. The present study aimed to compare the free radical scavenging and cytotoxic activities of a series of acylated and non-acylated kaempferol glycosides isolated from Stenochlaena palustris. The in silico binding interactions of the most cytotoxic glycoside with epidermal growth factor receptor was also evaluated. Results indicated that the free radical scavenging capability and cytotoxicity of kaempferol 3-O-β-D-glucopyranoside were enhanced through acylation with selected hydroxycinnamoyl groups, whereas mono-acylation did not improve both activities. Molecular docking study revealed that di-acylation was essential for the compound to bind to five major active sites of the receptor. Kaempferol 3-O-β-D-glucopyranosides that are di-acylated may be further explored for their chemopreventive and anticancer properties due to their significant antioxidant and cytotoxic properties
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