AMBER force field parameters for the Zn (II) ions of the tunneling-fold enzymes GTP cyclohydrolase I and 6-pyruvoyl tetrahydropterin synthase:
- Authors: Khairallah, Afrah , Tastan Bishop, Özlem , Moses, Vuyani
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/163068 , vital:41009 , DOI: 10.1080/07391102.2020.1796800
- Description: The folate biosynthesis pathway is an essential pathway for cell growth and survival. Folate derivatives serve as a source of the one-carbon units in several intracellular metabolic reactions. Rapidly dividing cells rely heavily on the availability of folate derivatives for their proliferation. As a result, drugs targeting this pathway have shown to be effective against tumor cells and pathogens, but drug resistance against the available antifolate drugs emerged quickly. Therefore, there is a need to develop new treatment strategies and identify alternative metabolic targets. The two de novo folate biosynthesis pathway enzymes, GTP cyclohydrolase I (GCH1) and 6-pyruvoyl tetrahydropterin synthase (PTPS), can provide an alternative strategy to overcome the drug resistance that emerged in the two primary targeted enzymes dihydrofolate reductase and dihydropteroate synthase.
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- Date Issued: 2020
Anti-HIV-1 integrase potency of methylgallate from Alchornea cordifolia using in vitro and in silico approaches:
- Authors: Noundou, Xavier S , Musyoka, Thommas M , Moses, Vuyani , Ndinteh, Derek T , Mnkandhla, Dumisani , Hoppe, Heinrich C , Tastan Bishop, Özlem , Krause, Rui W M
- Date: 2019
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/162975 , vital:41001 , https://0-doi.org.wam.seals.ac.za/10.1038/s41598-019-41403-x
- Description: According to the 2018 report of the United Nations Programme on HIV/AIDS (UNAIDS), acquired immune deficiency syndrome (AIDS), a disease caused by the human immunodeficiency virus (HIV), remains a significant public health problem. The non-existence of a cure or effective vaccine for the disease and the associated emergence of resistant viral strains imply an urgent need for the discovery of novel anti-HIV drug candidates. The current study aimed to identify potential anti-retroviral compounds from Alchornea cordifolia.
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- Date Issued: 2019
The determination of CHARMM force field parameters for the Mg2+ containing HIV-1 integrase:
- Authors: Musyoka, Thommas M , Tastan Bishop, Özlem , Lobb, Kevin A , Moses, Vuyani
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/148139 , vital:38713 , DOI: 10.1016/j.cplett.2018.09.019
- Description: The HIV integrase enzyme is a validated drug target. However, its potential has remained largely unexploited until recently due to lack of structural and mechanistic information. Its catalytic core domain (CCD) is crucial for the viral-human DNA integration making integrase an ideal target for inhibitor design. However, in order to do so, force field parameters for the integrase magnesium ion need to be established. Quantum mechanical calculations were used to derive force field parameters which were validated through molecular dynamics studies. Our results show that the parameters determined accurately maintain the integrity of the metal pocket of the integrase CCD.
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- Date Issued: 2018
The evaluation and validation of copper (II) force field parameters of the Auxiliary Activity family 9 enzymes:
- Authors: Moses, Vuyani , Tastan Bishop, Özlem , Lobb, Kevin A
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/148206 , vital:38719 , DOI: 10.1016/j.cplett.2017.04.022
- Description: The Auxiliary Activity family 9 (AA9) proteins are Cu2+ coordinating enzymes which are crucial for the early stages of cellulose degradation. In this study, the force field parameters for copper-containing bonds in the Type 1 AA9 protein active site were established and used in a molecular dynamics simulation on a solvated, neutralized system containing an AA9 protein, Cu2+ and a β-cellulose surface. The copper to cellulose interaction was evident during the dynamics, which could also be accelerated by the use of high Cu O van der Waals parameters. The interaction of AA9, Cu2+ and cellulose is described in detail.
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- Date Issued: 2017
Bioinformatic characterization of type-specific sequence and structural features in auxiliary activity family 9 proteins:
- Authors: Moses, Vuyani , Hatherley, Rowan , Tastan Bishop, Özlem
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/148358 , vital:38732 , DOI: 10.1186/s13068-016-0655-2
- Description: Due to the impending depletion of fossil fuels, it has become important to identify alternative energy sources. The biofuel industry has proven to be a promising alternative. However, owing to the complex nature of plant biomass, hence the degradation, biofuel production remains a challenge. The copper-dependent Auxiliary Activity family 9 (AA9) proteins have been found to act synergistically with other cellulose-degrading enzymes resulting in an increased rate of cellulose breakdown. AA9 proteins are lytic polysaccharide monooxygenase (LPMO) enzymes, otherwise known as polysaccharide monooxygenases (PMOs). They are further classified as Type 1, 2 or 3 PMOs, depending on the different cleavage products formed. As AA9 proteins are known to exhibit low sequence conservation, the analysis of unique features of AA9 domains of these enzymes should provide insights for the better understanding of how different AA9 PMO types function.
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- Date Issued: 2016