| 1. |
- Cleland, Dougal, et al.
(författare)
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Molecular dynamics approaches to the design and synthesis of PCB targeting molecularly imprinted polymers: interference to monomer-template interactions in imprinting of 1,2,3-trichlorobenzene
- 2014
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Ingår i: Organic and biomolecular chemistry. - : Royal Society of Chemistry (RSC). - 1477-0520 .- 1477-0539. ; 12:5, s. 844-853
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Tidskriftsartikel (refereegranskat)abstract
- The interactions between each component of the pre-polymerisation mixtures used in the synthesis of molecularly imprinted polymers (MIP) specific for 1,2,3,4,5-pentachlorobenzene (1) and 1,2,3-trichlorobenzene (2) were examined in four molecular dynamics simulations. These simulations revealed that the relative frequency of functional monomer template (FM T) interactions was consistent with results obtained by the synthesis and evaluation of the actual MIPs. The higher frequency of 1 interaction with tri-methylstyrene (TMS; 54.7%) than 1 interaction with pentafluorostyrene (PFS; 44.7%) correlated with a higher imprinting factor (IF) of 2.1 vs. 1.7 for each functional monomer respectively. The higher frequency of PFS interactions with 2 (29.6%) than TMS interactions with 2 (1.9%) also correlated well with the observed differences in IF (3.7) of 2 MIPs imprinted using PFS as the FM than the IF (2,8) of 2 MIPs imprinted using TMS as the FM. The TMS-1 interaction dominated the molecular simulation due to high interaction energies, but the weaker TMS-2 resulted in low interaction maintenance, and thus lower IF values. Examination of the other pre-polymerisation mixture components revealed that the low levels of TMS-2 interaction was, in part, due to interference caused by the cross linker (CL) ethyleneglycol dimethylacrylate (EGDMA) interactions with TMS. The main reason was, however, attributed to MeOH interactions with TMS in both a hydrogen bond and perpendicular configuration. This positioned a MeOH directly above the it-orbital of all TMS for an average of 63.8% of MD2 creating significant interference to pi-pi stacking interactions between 2 and TMS. These findings are consistent with the deviation from the 'normal' molecularly imprinted polymer synthesis ratio of 1 : 4 : 20 (T : FM : CL) of 20 : 1 : 29 and 15 : 6 : 29 observed with 2 and TMS and PFS respectively. Our molecular dynamics simulations correctly predicted the high level of interference from other MIP synthesis components. The effect on PFS-1 interaction by MeOH was significantly lower and thus this system was not adversely affected.
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| 2. |
- Hill, Timothy A., et al.
(författare)
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Iminochromene Inhibitors of Dynamins I and II GTPase Activity and Endocytosis
- 2010
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Ingår i: Journal of Medicinal Chemistry. - : American Chemical Society (ACS). - 0022-2623 .- 1520-4804. ; 53:10, s. 4094-4102
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Tidskriftsartikel (refereegranskat)abstract
- Herein we report the synthesis of discrete iminochromene (“iminodyn”) libraries (14−38) as potential inhibitors of dynamin GTPase. Thirteen iminodyns were active (IC50 values of 260 nM to 100 μM), with N,N-(ethane-1,2-diyl)bis(7,8-dihydroxy-2-iminochromene-3-carboxamide) (17), N,N-(ethane-1,2-diyl)bis(7,8-dihydroxy-2-iminochromene-3-carboxamide) (22), and N,N-(ethane-1,2-diyl)bis(7,8-dihydroxy-2-iminochromene-3-carboxamide) (23) (IC50 values of 330 ± 70, 450 ± 50, and 260 ± 80 nM, respectively) being the most potent. Five of the most potent iminodyns all inhibited dynamins I and II approximately equally. Iminodyn-22 displayed uncompetitive inhibition with respect to GTP. Selected iminodyns were evaluated for their ability to block receptor mediated endocytosis (RME, mediated by dynamin II) and synaptic vesicle endocytosis (SVE, mediated by dynamin I), with 17 showing no activity while 22 returned RME and SVE IC50 values of 10.7 ± 4.5 and 99.5 ± 1.7 μM, respectively. The iminodyns reported herein represent a new chemical class of the first nanomolar potent dynamin inhibitors that are also effective endocytosis inhibitors.
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| 3. |
- Howes, Mark T, et al.
(författare)
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Clathrin-independent carriers form a high capacity endocytic sorting system at the leading edge of migrating cells
- 2010
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Ingår i: Journal of Cell Biology. - : Rockefeller University Press. - 0021-9525 .- 1540-8140. ; 190:4, s. 675-691
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Tidskriftsartikel (refereegranskat)abstract
- Although the importance of clathrin- and caveolin-independent endocytic pathways has recently emerged, key aspects of these routes remain unknown. Using quantitative ultrastructural approaches, we show that clathrin-independent carriers (CLICs) account for approximately three times the volume internalized by the clathrin-mediated endocytic pathway, forming the major pathway involved in uptake of fluid and bulk membrane in fibroblasts. Electron tomographic analysis of the 3D morphology of the earliest carriers shows that they are multidomain organelles that form a complex sorting station as they mature. Proteomic analysis provides direct links between CLICs, cellular adhesion turnover, and migration. Consistent with this, CLIC-mediated endocytosis of key cargo proteins, CD44 and Thy-1, is polarized at the leading edge of migrating fibroblasts, while transient ablation of CLICs impairs their ability to migrate. These studies provide the first quantitative ultrastructural analysis and molecular characterization of the major endocytic pathway in fibroblasts, a pathway that provides rapid membrane turnover at the leading edge of migrating cells.
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| 4. |
- MacGregor, Kylie A, et al.
(författare)
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Development of quinone analogues as dynamin GTPase inhibitors
- 2014
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Ingår i: European Journal of Medicinal Chemistry. - : Elsevier BV. - 0223-5234 .- 1768-3254. ; 85, s. 191-206
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Tidskriftsartikel (refereegranskat)abstract
- Virtual screening of the ChemDiversity and ChemBridge compound databases against dynamin I (dynI) GTPase activity identified 2,5-bis-(benzylamino)-1,4-benzoquinone 1 as a 273 ± 106 μM inhibitor. In silico lead optimization and focused library-led synthesis resulted in the development of four discrete benzoquinone/naphthoquinone based compound libraries comprising 54 compounds in total. Sixteen analogues were more potent than lead 1, with 2,5-bis-(4-hydroxyanilino)-1,4-benzoquinone (45) and 2,5-bis(4-carboxyanilino)-1,4-benzoquinone (49) the most active with IC50 values of 11.1 ± 3.6 and 10.6 ± 1.6 μM respectively. Molecular modelling suggested a number of hydrogen bonding and hydrophobic interactions were involved in stabilization of 49 within the dynI GTP binding site. Six of the most active inhibitors were evaluated for potential inhibition of clathrin-mediated endocytosis (CME). Quinone 45 was the most effective CME inhibitor with an IC50(CME) of 36 ± 16 μM.
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| 5. |
- McGeachie, Andrew B, et al.
(författare)
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Pyrimidyn Compounds : Dual-Action Small Molecule Pyrimidine-Based Dynamin Inhibitors
- 2013
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Ingår i: ACS Chemical Biology. - : American Chemical Society (ACS). - 1554-8929 .- 1554-8937. ; 8:7, s. 1507-1518
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Tidskriftsartikel (refereegranskat)abstract
- Dynamin is required for clathrin-mediated endocytosis (CME). Its GTPase activity is stimulated by phospholipid binding to its PH domain, which induces helical oligomerization. We have designed a series of novel pyrimidine-based "Pyrimidyn" compounds that inhibit the lipid-stimulated GTPase activity of full length dynamin I and II with similar potency. The most potent analogue, Pyrimidyn 7, has an IC50 of 1.1 μM for dynamin I and 1.8 μM for dynamin II, making it among the most potent dynamin inhibitors identified to date. We investigated the mechanism of action of the Pyrimidyn compounds in detail by examining the kinetics of Pyrimidyn 7 inhibition of dynamin. The compound competitively inhibits both GTP and phospholipid interactions with dynamin I. While both mechanisms of action have been previously observed separately, this is the first inhibitor series to incorporate both and thereby to target two distinct domains of dynamin. Pyrimidyn 6 and 7 reversibly inhibit CME of both transferrin and EGF in a number of non-neuronal cell lines as well as inhibiting synaptic vesicle endocytosis (SVE) in nerve terminals. Therefore, Pyrimidyn compounds block endocytosis by directly competing with GTP and lipid binding to dynamin, limiting both the recruitment of dynamin to membranes and its activation. This dual mode of action provides an important new tool for molecular dissection of dynamin's role in endocytosis.
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| 6. |
- Odell, Luke R, et al.
(författare)
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The Pthaladyns : GTP Competitive Inhibitors of Dynamin I and II GTPase Derived from Virtual Screening
- 2010
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Ingår i: Journal of Medicinal Chemistry. - : American Chemical Society (ACS). - 0022-2623 .- 1520-4804. ; 53:14, s. 5267-5280
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Tidskriftsartikel (refereegranskat)abstract
- We report the development of a homology model for the GTP binding domain of human dynamin I based on the corresponding crystal structure of Dictyostelium discoidum dynamin A. Virtual screening identified 2-[(2-biphenyl-2-yl-1,3-dioxo-2,3-dihydro-1H-isoindole-5-carbonyl)amino]-4-chlorobenzoic acid (1) as a 170 μM potent inhibitor. Homology modeling- and focused library-led synthesis resulted in development of a series of active compounds (the “pthaladyns”) with 4-chloro-2-(2-(4-(hydroxymethyl)phenyl)-1,3-dioxoisoindoline-5-carboxamido)benzoic acid (29), a 4.58 ± 0.06 μM dynamin I GTPase inhibitor. Pthaladyn-29 displays borderline selectivity for dynamin I relative to dynamin II (5−10 fold). Only pthaladyn-23 (dynamin I IC50 17.4 ± 5.8 μM) was an effective inhibitor of dynamin I mediated synaptic vesicle endocytosis in brain synaptosomes with an IC50 of 12.9 ± 5.9 μM. This compound was also competitive with respect to Mg2+·GTP. Thus the pthaladyns are the first GTP competitive inhibitors of dynamin I and II GTPase and may be effective new tools for the study of neuronal endocytosis.
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