180 results found
Miller DM, Findlay HE, Ces O, et al., 2016, Light-activated control of protein channel assembly mediated by membrane mechanics, Nanotechnology, Vol: 27, Pages: 1-10, ISSN: 1361-6528
Photochemical processes provide versatile triggers of chemical reactions. Here, we use a photoactivated lipid switch to modulate the folding and assembly of a protein channel within a model biological membrane. In contrast to the information rich field of water-soluble protein folding, there is only a limited understanding of the assembly of proteins that are integral to biological membranes. It is however possible to exploit the foreboding hydrophobic lipid environment and control membrane protein folding via lipid bilayer mechanics. Mechanical properties such as lipid chain lateral pressure influence the insertion and folding of proteins in membranes, with different stages of folding having contrasting sensitivities to the bilayer properties. Studies to date have relied on altering bilayer properties through lipid compositional changes made at equilibrium, and thus can only be made before or after folding. We show that light-activation of photoisomerisable di-(5-[[4-(4-butylphenyl)azo]phenoxy]pentyl)phosphate (4-Azo-5P) lipids influences the folding and assembly of the pentameric bacterial mechanosensitive channel MscL. The use of a photochemical reaction enables the bilayer properties to be altered during folding, which is unprecedented. This mechanical manipulation during folding, allows for optimisation of different stages of the component insertion, folding and assembly steps within the same lipid system. The photochemical approach offers the potential to control channel assembly when generating synthetic devices that exploit the mechanosensitive protein as a nanovalve.
Furse S, Brooks NJ, Woscholski R, et al., 2016, Pressure-dependent inverse bicontinuous cubic phase formation in a phosphatidylinositol 4-phosphate/phosphatidylcholine system, Chemical Data Collections, Vol: 3-4, Pages: 15-20, ISSN: 2405-8300
In this paper, we report the inositide-driven formation of an inverse bicontinuous cubic phase with space group Ia3d (QIIG, gyroid phase). The system under study consisted of distearoylphosphatidylinositol 4-phosphate (DSPIP) and dioleoylphosphatidylcholine at a molar ratio of 1:49, with a physiological concentration of magnesium ions at pH 7·4. The behaviour of the system was monitored as a function of temperature and pressure. The formation of the phase with Ia3d geometry was recorded repeatably at high pressure, and occurred more readily at higher temperatures. We conclude that the Ia3d phase formed is a thermodynamically stable structure, and that DSPIP is a potent source of membrane curvature that can drive the formation of mesophases with both 2- and 3D geometry.
Seddon JM, Brooks NJ, Ces O, et al., 2015, Lipid bicontinuous cubic phases: effects of chain-branching and hydrostatic pressure, 10th European-Biophysical-Societies-Association (EBSA) European Biophysics Congress, Publisher: SPRINGER, Pages: S187-S187, ISSN: 0175-7571
Barriga HMG, Bazin R, Templer RH, et al., 2015, Buffer-Induced Swelling and Vesicle Budding in Binary Lipid Mixtures of Dioleoylphosphatidylcholine:Dioleoylphosphatidylethanolamine and Dioleoylphosphatidylcholine:Lysophosphatidylcholine Using Small-Angle X-ray Scattering and P-31 Static NMR, LANGMUIR, Vol: 31, Pages: 2979-2987, ISSN: 0743-7463
Tang T-YD, Brooks NJ, Ces O, et al., 2015, Structural studies of the lamellar to bicontinuous gyroid cubic (Q(II)(G)) phase transitions under limited hydration conditions, SOFT MATTER, Vol: 11, Pages: 1991-1997, ISSN: 1744-683X
Furse S, Mak L, Tate EW, et al., 2015, Synthesis of unsaturated phosphatidylinositol 4-phosphates and the effects of substrate unsaturation on SopB phosphatase activity, ORGANIC & BIOMOLECULAR CHEMISTRY, Vol: 13, Pages: 2001-2011, ISSN: 1477-0520
Barriga HMG, Booth P, Haylock S, et al., 2014, Droplet interface bilayer reconstitution and activity measurement of the mechanosensitive channel of large conductance from Escherichia coli, Journal of the Royal Society Interface, Vol: 11, ISSN: 1742-5662
Droplet interface bilayers (DIBs) provide an exciting new platform for the study of membrane proteins in stable bilayers of controlled composition. To date, the successful reconstitution and activity measurement of membrane proteins in DIBs has relied on the use of the synthetic lipid 1,2-diphytanoyl-sn-glycero-3-phosphocholine (DPhPC). We report the functional reconstitution of the mechanosensitive channel of large conductance (MscL) into DIBs composed of 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC), a lipid of significantly greater biological relevance than DPhPC. MscL functionality has been demonstrated using a fluorescence-based assay, showing that dye flow occurs across the DIB when MscL is gated by the cysteine reactive chemical 2-(trimethylammonium)ethyl methane thiosulfonate bromide (MTSET). MscL has already been the subject of a number of studies investigating its interaction with the membrane. We propose that this method will pave the way for future MscL studies looking in detail at the effects of controlled composition or membrane asymmetry on MscL activity using biologically relevant lipids and will also be applicable to other lipid–protein systems, paving the way for the study of membrane proteins in DIBs with biologically relevant lipids.
Tang T-YD, Seddon AM, Jeworrek C, et al., 2014, The effects of pressure and temperature on the energetics and pivotal surface in a monoacylglycerol/water gyroid inverse bicontinuous cubic phase, SOFT MATTER, Vol: 10, Pages: 3009-3015, ISSN: 1744-683X
Wang L, Sharifzadeh M, Templer R, et al., 2013, Bioethanol production from various waste papers: Economic feasibility and sensitivity analysis, Applied Energy, Vol: 111, Pages: 1172-1182, ISSN: 0306-2619
Miller D, Booth PJ, Seddon JM, et al., 2013, Protocell design through modular compartmentalization, JOURNAL OF THE ROYAL SOCIETY INTERFACE, Vol: 10, ISSN: 1742-5689
Purushothaman S, Gauthe BLLE, Brooks NJ, et al., 2013, Automated laboratory based X-ray beamline with multi-capillary sample chamber, REVIEW OF SCIENTIFIC INSTRUMENTS, Vol: 84, ISSN: 0034-6748
Tyler AII, Shearman GC, Parsons ES, et al., 2013, Tuning curvature in inverse micellar and bicontinuous cubic phases, 9th European-Biophysical-Societies-Association Congress, Publisher: SPRINGER, Pages: S140-S140, ISSN: 0175-7571
Kulkarni CV, Ces O, Templer RH, et al., 2013, Pressure effects on a protein-lipid model membrane, SOFT MATTER, Vol: 9, Pages: 6525-6531, ISSN: 1744-683X
Tang TYD, Brooks NJ, Jeworrek C, et al., 2012, Hydrostatic Pressure Eﬀects on the Lamellar to Gyroid Cubic Phase Transition of Monolinolein at Limited Hydration, Langmuir
Htun N, Jiang Y, Mahajan D, et al., 2012, Preface to Special Topic: Low-Carbon Society for a Green Economy, JOURNAL OF RENEWABLE AND SUSTAINABLE ENERGY, Vol: 4, ISSN: 1941-7012
Charalambous K, Booth PJ, Woscholski R, et al., 2012, Engineering de Novo Membrane-Mediated Protein-Protein Communication Networks, JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, Vol: 134, Pages: 5746-5749, ISSN: 0002-7863
Wang L, Templer R, Murphy RJ, 2012, Environmental sustainability of bioethanol production from waste papers: sensitivity to the system boundary, Energy & Environmental Science, Vol: 5, Pages: 8281-8293, ISSN: 1754-5692
The production of bioethanol from various waste papers (newspaper, office paper, magazine and cardboard) was evaluated from an environmental standpoint. 'Cradle-to-grave' (or 'well-to-wheel') analyses were performed using a Life Cycle Assessment (LCA) approach with the aims of identifying the key drivers of environmental impact in the bioethanol supply chains and of comparing the environmental footprints of various bioethanol supply chains with those of conventional petrol. Base cases (bioethanol production from various waste papers) and two state-of-the-art cases including pre-treatment of office paper by dilute acid (DA) and of newspaper by an oxidative lime (OL) process were constructed using laboratory data, expert consultations, literature values, and simulation in AspenPlus[trade mark sign] software. Contribution analysis showed enzyme production needed for hydrolysis of the papers to be the main contributor to the environmental profiles for bioethanol in the base cases. The production of process heat and hydrochloric acid respectively were the main contributors to the bioethanol environmental profiles for office paper-to-bioethanol with DA pre-treatment and newspaper-to-bioethanol with OL pre-treatment. Overall, bioethanol produced from newspaper, magazine paper and cardboard was found to have a lower environmental impact than the conventional transport fuel petrol. However, this conclusion is significantly affected by the system boundaries used for the analysis. When an expanded system boundary is applied to consider virgin and recycled paper production as the potential consequential effects within the bioethanol and petrol systems respectively, office paper-derived bioethanol systems emerge as the most environmentally favourable over petrol.
Wang L, Templer R, Murphy RJ, 2012, High-solids loading enzymatic hydrolysis of waste papers for biofuel production, Applied Energy, Vol: 99, Pages: 23 - 31-23 - 31, ISSN: 0306-2619
Wang L, Sharifzadeh M, Templer R, et al., 2012, Technology performance and economic feasibility of bioethanol production from various waste papers, Energy and Environmental Science, Vol: 5, Pages: 5717-5730
Wang L, Sharifzadeh M, Templer R, et al., 2012, Technology performance and economic feasibility of bioethanol production from various waste papers, Energy & Environmental Science, Vol: 5, Pages: 5717-5730, ISSN: 1754-5692
Producing bioethanol from various wastes is a promising strategy to meet part of the transport energy demand and also to contribute to waste management. Waste papers (newspaper, office paper, magazines and cardboard in this work) with their 50% to 70% carbohydrate content are potential raw materials for bioethanol production. From both technical and economic aspects, bioethanol production processes for various waste papers were evaluated in this study. High-solids loading (15% w/w) enzymatic hydrolyses using two enzyme alternatives (Celluclast 1.5 L supplemented with Novozyme 188 and Cellic Ctec 1) achieved glucan conversion efficiencies from waste papers of 50% to 76%. Base case process models developed using these experimental data were then applied to an economic analysis to determine the minimum ethanol selling price (MESP) for bioethanol derived from the waste papers using a discounted cash flow method. The effects of several processing parameters: alternative product recovery processes, enzyme loading, enzymatic hydrolysis residence time and two enzyme alternatives on the MESP are explored. Bioethanol produced from cardboard (using Cellic Ctec 1) resulted in the lowest MESP. Two state-of-the-art technologies, dilute acid pre-treatment on office paper and oxidative lime pre-treatment on newspaper, were also investigated. This study suggests that bioethanol production from waste papers is feasible and profitable from both technical and economic points of view.
Furse S, Brooks NJ, Seddon AM, et al., 2012, Lipid membrane curvature induced by distearoyl phosphatidylinositol 4-phosphate, Soft Matter
Wang L, Templer R, Murphy RJ, 2012, A Life Cycle Assessment (LCA) comparison of three management options for waste papers: Bioethanol production, recycling and incineration with energy recovery, Bioresource Technology, Vol: 120, Pages: 89 - 98-89 - 98, ISSN: 0960-8524
Templer R, van der Wielen L, 2011, Biorenewables, the bio-based economy and sustainability, INTERFACE FOCUS, Vol: 1, Pages: 187-188, ISSN: 2042-8898
Salehi-Reyhani A, Kaplinsky J, Burgin E, et al., 2011, A first step towards practical single cell proteomics: a microfluidic antibodycapture chip with TIRF detection, Lab Chip, Vol: 11, Pages: 1256-1261
We have developed a generic platform to undertake the analysis of protein copy number from singlecells. The approach described here is ‘all-optical’ whereby single cells are manipulated into separate analysis chambers using an optical trap; single cells are lysed by a shock wave caused by laser-induced microcavitation, and the protein released from a single cell is measured by total internal reflection microscopy as it is bound to micro-printed antibody spots within the device. The platform was tested using GFP transfected cells and the relative precision of the measurement method was determined to be 88%. Single cell measurements were also made on a breast cancer cell line to measure the relative levels of unlabelled human tumour suppressor protein p53 using a chip incorporating an antibody sandwich assay format. These results suggest that this is a viable method for measuring relative protein levels in single cells.
Brooks NJ, Ces O, Templer RH, et al., 2011, Pressure effects on lipid membrane structure and dynamics, CHEMISTRY AND PHYSICS OF LIPIDS, Vol: 164, Pages: 89-98, ISSN: 0009-3084
Tyler AII, Shearman GC, Brooks NJ, et al., 2011, Hydrostatic pressure effects on a hydrated lipid inverse micellar Fd3m cubic phase, PHYSICAL CHEMISTRY CHEMICAL PHYSICS, Vol: 13, Pages: 3033-3038, ISSN: 1463-9076
Shearman GC, Brooks NJ, Tiddy GJT, et al., 2011, A lyotropic inverse ribbon phase in a branched-chain polyoxyethylene surfactant: pressure effects, SOFT MATTER, Vol: 7, Pages: 4386-4390, ISSN: 1744-683X
Brooks NJ, Gauthe BLLE, Terrill NJ, et al., 2010, Automated high pressure cell for pressure jump x-ray diffraction, REVIEW OF SCIENTIFIC INSTRUMENTS, Vol: 81, ISSN: 0034-6748
Tyler AII, Shearman GC, Brooks NJ, et al., 2010, High Pressure Static and Time-Resolved X-Ray Studies of Inverse Phases in Cholesterol / Lipid Mixtures, BIOPHYSICAL JOURNAL, Vol: 98, Pages: 231A-231A, ISSN: 0006-3495
Kulkarni CV, Tang T-Y, Seddon AM, et al., 2010, Engineering bicontinuous cubic structures at the nanoscale-the role of chain splay, SOFT MATTER, Vol: 6, Pages: 3191-3194, ISSN: 1744-683X
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