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Williamson PTF, Zandomeneghi G, Barrantes FJ, Watts A, Meier BH. Structural and dynamic studies of the γ-M4 trans-membrane domain of the nicotinic acetylcholine receptor. Mol Membr Biol 2009; 22:485-96. [PMID: 16373320 DOI: 10.1080/09687860500370653] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
A structural characterization of a synthetic peptide corresponding to the fourth transmembrane domain (M4-TMD) of the gamma-subunit of the nicotinic acetylcholine receptor from Torpedo californica has been undertaken. Solid-state NMR and CD spectroscopy studies indicate that upon reconstitution into lipid vesicles or magnetically aligned lipid bilayers, the synthetic M4-TMD adopts a linear alpha-helical conformation with the helix aligned within 15 degrees of the membrane normal. Furthermore, analysis of the motional averaging of anisotropic interactions present in the solid-state NMR spectra of the reconstituted peptide, indicate that the dynamics of the peptide within the bilayer are highly sensitive to the phase adopted by the lipid bilayer, providing an insight into how the interaction of lipids with this domain may play a important role in the modulation of this receptor by its lipid environment.
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Åberg G, Aigbirhio FI, Alexakis E, Al-Maharik N, Almi M, Ambacher Y, Andersson S, Athlan A, Badman G, Baldwin SA, Baumann M, Baxendale IR, Botting NP, Bragg RA, Brown JA, Burton A, Bushby N, Cable K, Campbell G, Carr R, Carroll M, Chen L, Christlieb M, Davies P, Ellames GJ, Ellis W, Elmore C, Fryatt T, Geach N, Harding JR, Hartmann S, Harwood S, Hayward JJ, Henderson PJF, Herbert RB, Heys JR, Hölzl S, Hopkin MD, Horn P, Ilyas T, Irvine S, Jackson SD, Jin J, Keats A, Kennedy AR, Kerr WJ, Kitching MO, Landreau C, Lanners S, Lawrence R, Lawrie KWM, Ley SV, Little G, Lockley WJS, Maier D, Manning C, McNeill A, Middleton DA, Montgomery S, Morrison JJ, Mrzljak L, Newman J, Newsome J, Nikbin-Roudsari N, Nilsson GN, Oldfield MF, Patching SG, Procter DJ, Randall G, Robertson AA, Rummel CS, Rustidge D, Sherhod R, Shipley N, Smith CD, Smith CJ, Smith DI, Song C, Tamborini L, Waterhouse I, Watts A, Werkheiser JL, Williams G, Willis CL, Woodward P, Yan R, Young G, Zhang Q. 16th International Isotope Society (UK group) Symposium. J Labelled Comp Radiopharm 2008. [DOI: 10.1002/jlcr.1513] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Mehnert T, Routh A, Judge PJ, Lam YH, Fischer D, Watts A, Fischer WB. Biophysical characterization of Vpu from HIV-1 suggests a channel-pore dualism. Proteins 2008; 70:1488-97. [PMID: 17910056 PMCID: PMC7167847 DOI: 10.1002/prot.21642] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Vpu from HIV‐1 is an 81 amino acid type I integral membrane protein which consists of a cytoplasmic and a transmembrane (TM) domain. The TM domain is known to alter membrane permeability for ions and substrates when inserted into artificial membranes. Peptides corresponding to the TM domain of Vpu (Vpu1‐32) and mutant peptides (Vpu1‐32‐W23L, Vpu1‐32‐R31V, Vpu1‐32‐S24L) have been synthesized and reconstituted into artificial lipid bilayers. All peptides show channel activity with a main conductance level of around 20 pS. Vpu1‐32‐W23L has a considerable flickering pattern in the recordings and longer open times than Vpu1‐32. Whilst recordings for Vpu1‐32‐R31V are almost indistinguishable from those of the WT peptide, recordings for Vpu1‐32‐S24L do not exhibit any noticeable channel activity. Recordings of WT peptide and Vpu1‐32‐W23L indicate Michaelis–Menten behavior when the salt concentration is increased. Both peptide channels follow the Eisenman series I, indicative for a weak ion channel with almost pore like characteristics. Proteins 2008. © 2007 Wiley‐Liss, Inc.
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Varga K, Aslimovska L, Parrot I, Dauvergne MT, Haertlein M, Forsyth VT, Watts A. NMR crystallography: the effect of deuteration on high resolution 13C solid state NMR spectra of a 7-TM protein. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2007; 1768:3029-35. [PMID: 18001693 DOI: 10.1016/j.bbamem.2007.09.023] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/20/2007] [Revised: 09/24/2007] [Accepted: 09/27/2007] [Indexed: 11/24/2022]
Abstract
The effect of deuteration on the 13C linewidths of U-13C, 15N 2D crystalline bacteriorhodopsin (bR) from Halobacterium salinarium, a 248-amino acid protein with seven-transmembrane (7TM) spanning regions, has been studied in purple membranes as a prelude to potential structural studies. Spectral doubling of resonances was observed for receptor expressed in 2H medium (for both 50:50% 1H:2H, and a more highly deuterated form) with the resonances being of similar intensities and separated by <0.3 ppm in the methyl spectral regions in which they were readily distinguished. Line-widths of the methyl side chains were not significantly altered when the protein was expressed in highly deuterated medium compared to growth in fully protonated medium (spectral line widths were about 0.5 ppm on average for receptor expressed both in the fully protonated and highly deuterated media from the C delta, C gamma 1, and C gamma 2 Ile 13C signals observed in the direct, 21-39 ppm, and indirect, 9-17 ppm, dimensions). The measured 13C NMR line-widths observed for both protonated and deuterated form of the receptor are sufficiently narrow, indicating that this crystalline protein morphology is suitable for structural studies. 1) decoupling comparison of the protonated and deuterated bR imply that deuteration may be advantageous for samples in which low power 1H decoupling is required.
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Harding PJ, Attrill H, Ross S, Koeppe JR, Kapanidis AN, Watts A. Neurotensin receptor type 1: Escherichia coli expression, purification, characterization and biophysical study. Biochem Soc Trans 2007; 35:760-3. [PMID: 17635142 DOI: 10.1042/bst0350760] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
NT (neurotensin) is an endogenous tridecapeptide neurotransmitter found in the central nervous system and gastrointestinal tract. One receptor for NT, NTS1, belongs to the GPCR (G-protein-coupled receptor) superfamily, has seven putative transmembrane domains, and is being studied by a range of single-molecule, functional and structural approaches. To enable biophysical characterization, sufficient quantities of the receptor need to be expressed and purified in an active form. To this end, rat NTS1 has been expressed in Escherichia coli in an active ligand-binding form at the cell membrane and purified in sufficient amounts for structural biology studies either with or without fluorescent protein [YFP (yellow fluorescent protein) and CFP (cyan fluorescent protein)] fusions. Ligand binding has been demonstrated in a novel SPR (surface plasmon resonance) approach, as well as by conventional radioligand binding measurements. These improvements in production of NTS1 now open up the possibility of direct structural studies, such as solid-state NMR to interrogate the NT-binding site, EM (electron microscopy), and X-ray crystallography and NMR.
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Mehnert T, Lam YH, Judge PJ, Routh A, Fischer D, Watts A, Fischer WB. Towards a Mechanism of Function of the Viral Ion Channel Vpu from HIV-1. J Biomol Struct Dyn 2007; 24:589-96. [PMID: 17508781 DOI: 10.1080/07391102.2007.10507148] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
Vpu, an integral membrane protein encoded in HIV-1, is implicated in the release of new virus particles from infected cells, presumably mediated by ion channel activity of homo-oligomeric Vpu bundles. Reconstitution of both full length Vpu(1-81) and a short, the transmembrane (TM) domain comprising peptide Vpu(1-32) into bilayers under a constant electric field results in an asymmetric orientation of those channels. For both cases, channel activity with similar kinetics is observed. Channels can open and remain open within a broad series of conductance states even if a small or no electric potential is applied. The mean open time for Vpu peptide channels is voltage-independent. The rate of channel opening shows a biphasic voltage activation, implicating that the gating is influenced by the interaction of the dipole moments of the TM helices with an electric field.
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Warren-Forward H, Arthur L, Hobson L, Skinner R, Watts A, Clapham K, Lou D, Cook A. An assessment of exposure indices in computed radiography for the posterior–anterior chest and the lateral lumbar spine. Br J Radiol 2007; 80:26-31. [PMID: 16916804 DOI: 10.1259/bjr/59538862] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
Studies have indicated that computed radiography (CR) can increase radiation dose to the patient, leading to potential biological effects. Although manufacturers have set parameters to safeguard against overexposure, it is unclear whether these are being used by radiographers or if their recommended values are consistent with the ALARA principle. The research aims are to investigate (i) whether radiographers are producing images with exposure indices within the manufacturers recommended range (MRR); (ii) the phenomenon of exposure creep, and (iii) the relationship between exposure indices (EIs) and radiation dose. A retrospective analysis of exposure indices over an 18-month period for the posteroanterior (PA) chest and lateral (LAT) lumbar spine at two centres using Kodak 800 and 850 CR systems was conducted. A phantom study was performed to assess the relationship between EI and entrance surface dose (ESD) for fixed and varying tube potentials. Kodak recommends that images have EIs between 1700 and 1900. Thirty percent of LAT lumbar spine examinations at hospital B and 38% of PA chest examinations at hospital A were produced with EIs below 1700. In the phantom study, when using a varied tube potential (70-125 kVp) and maintaining a constant EI of 1550, ESD was reduced by 56%. All clinical and phantom images were assessed to be of a diagnostic quality. The retrospective results indicate that there is a potential to reduce the MRR and optimize patient dose. There is also evidence to suggest that EI is not a reliable indicator of patient dose. The authors recommend that staff training is essential on these newer systems.
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Kim CG, Lemaitre V, Watts A, Fischer WB. Drug–protein interaction with Vpu from HIV-1: proposing binding sites for amiloride and one of its derivatives. Anal Bioanal Chem 2006; 386:2213-7. [PMID: 17082882 DOI: 10.1007/s00216-006-0832-4] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2006] [Revised: 09/01/2006] [Accepted: 09/05/2006] [Indexed: 10/24/2022]
Abstract
Vpu is an 81-amino-acid auxiliary protein of the genome of HIV-1. It is proposed that one of its roles is to enhance particle release by self-assembling to form water-filled channels enabling the flux of ions at the site of the plasma membrane of the infected cell. Hexamethylene amiloride has been shown to block Vpu channel activity when the protein is reconstituted into lipid bilayers. In a docking approach with monomeric, pentameric and hexameric bundle models of Vpu corresponding to the transmembrane part of the protein, a putative binding site of hexamethylene amiloride is proposed and is compared with the site for the nonpotent amiloride. The binding mode for both ligands is achieved by optimizing hydrogen bond interactions with serines. Binding energies and binding constants are the lowest for protonated hexamethylene amiloride in the pentameric bundle.
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de Planque MRR, de Planque MRR, Mendes GP, Zagnoni M, Sandison ME, Fisher KH, Berry RM, Watts A, Morgan H. Controlled delivery of membrane proteins to artificial lipid bilayers by nystatin-ergosterol modulated vesicle fusion. ACTA ACUST UNITED AC 2006; 153:21-30. [PMID: 16671820 DOI: 10.1049/ip-nbt:20050039] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The study of ion channels and other membrane proteins and their potential use as biosensors and drug screening targets require their reconstitution in an artificial membrane. These applications would greatly benefit from microfabricated devices in which stable artificial lipid bilayers can be rapidly and reliably formed. However, the amount of protein delivered to the bilayer must be carefully controlled. A vesicle fusion technique is investigated where composite ion channels of the polyene antibiotic nystatin and the sterol ergosterol are employed to render protein-carrying vesicles fusogenic. After fusion with an ergosterol-free artificial bilayer, the nystatin-ergosterol channels do not dissociate immediately and thus cause a transient current signal that marks the vesicle fusion event. Experimental pitfalls of this method were identified, the influence of the nystatin and ergosterol concentration on the fusion rate and the shape of the fusion event marker was explored, and the number of different lipid species was reduced. Under these conditions, the -amyloid peptide could be delivered in a controlled manner to a standard planar bilayer. Additionally, electrical recordings were obtained of vesicles fusing with a planar lipid bilayer in a microfabricated device, demonstrating the suitability of nystatin-ergosterol modulated vesicle fusion for protein delivery within microsystems.
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Lemaitre V, Willbold D, Watts A, Fischer WB. Full Length Vpu from HIV-1: Combining Molecular Dynamics Simulations with NMR Spectroscopy. J Biomol Struct Dyn 2006; 23:485-96. [PMID: 16494498 DOI: 10.1080/07391102.2006.10507074] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
Based on structures made available by solution NMR, molecular models of the protein Vpu from HIV-1 were built and refined by 6 ns MD simulations in a fully hydrated lipid bilayer. Vpu is an 81 amino acid type I integral membrane protein encoded by the human immunodeficiency virus type-1 (HIV-1) and closely related simian immunodeficiency viruses (SIVs). Its role is to amplify viral release. Upon phosphorylation, the cytoplasmic domain adopts a more compact shape with helices 2 and 3 becoming almost parallel to each other. A loss of helicity for several residues belonging to the helices adjacent to both ends of the loop region containing serines 53 and 57 is observed. A fourth helix, present in one of the NMR-based structures of the cytoplasmic domain and located near the C-terminus, is lost upon phosphorylation.
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Howes A, Anupõld T, Lemaitre V, Kukol A, Watts A, Samoson A, Smith M, Dupree R. Enhancing resolution and sensitivity of 17O solid-state NMR through combining double rotation, 1H decoupling and satellite modulation for biomolecular applications. Chem Phys Lett 2006. [DOI: 10.1016/j.cplett.2006.01.061] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Bonev B, Grieve S, Herberstein ME, Kishore AI, Watts A, Separovic F. Orientational order of Australian spider silks as determined by solid-state NMR. Biopolymers 2006; 82:134-43. [PMID: 16463360 DOI: 10.1002/bip.20471] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
A simple solid-state NMR method was used to study the structure of (13)C- and (15)N-enriched silk from two Australian orb-web spider species, Nephila edulis and Argiope keyserlingi. Carbon-13 and (15)N spectra from alanine- or glycine-labeled oriented dragline silks were acquired with the fiber axis aligned parallel or perpendicular to the magnetic field. The fraction of oriented component was determined from each amino acid, alanine and glycine, using each nucleus independently, and attributed to the ordered crystalline domains in the silk. The relative fraction of ordered alanine was found to be higher than the fraction of ordered glycine, akin to the observation of alanine-rich domains in silk-worm (Bombyx mori) silk. A higher degree of crystallinity was observed in the dragline silk of N. edulis compared with A. keyserlingi, which correlates with the superior mechanical properties of the former.
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Prydal JI, Jenkins DR, Lovering A, Watts A. The pharmacokinetics of linezolid in the non-inflamed human eye. Br J Ophthalmol 2005; 89:1418-9. [PMID: 16234443 PMCID: PMC1772914 DOI: 10.1136/bjo.2005.073700] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
AIM This study describes the ocular pharmacokinetics of linezolid, an antibiotic with broad spectrum activity against those Gram positive bacteria that are the most frequent cause of postoperative endophthalmitis. METHOD Patients undergoing routine cataract surgery were given a single oral 600 mg dose of linezolid at a variable time before surgery. Aqueous and serum levels of linezolid were assayed by high performance liquid chromatography, and a pharmacokinetic curve constructed from the pooled results. RESULTS Orally administered linezolid rapidly achieves levels in the aqueous of non-inflamed eyes that exceed the concentration required to kill Gram positive bacteria (maximum mean concentration 6.8 (SD 1.2) microg/ml at 2-4 hours post-dose). An effective concentration is maintained for at least 12 hours, the standard interdose interval for this antimicrobial. CONCLUSION Linezolid offers the possibility of a rapid, oral approach to effective treatment of most cases of postoperative endophthalmitis, with the potential of improving visual outcome.
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Amin R, Turner C, van Aken S, Bahu TK, Watts A, Lindsell DRM, Dalton RN, Dunger DB. The relationship between microalbuminuria and glomerular filtration rate in young type 1 diabetic subjects: The Oxford Regional Prospective Study. Kidney Int 2005; 68:1740-9. [PMID: 16164650 DOI: 10.1111/j.1523-1755.2005.00590.x] [Citation(s) in RCA: 94] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
BACKGROUND The purpose of this study was to examine the relationship between glomerular filtration rate (GFR) measured at 5 years' diabetes duration and annual urine albumin excretion in a prospective cohort of children with type 1 diabetes (T1DM). METHODS Three hundred and eight children were followed from diagnosis of T1DM [aged 9.8 years (range 0.4-15.9) for a median duration of 10.9 years (6.0-17.8) with annual assessments comprising measurement of HbA1(c) and 3 urine samples for albumin:creatinine ratio (ACR). GFR was measured in all children at 5 years' diabetes duration. RESULTS Two hundred forty-three (78.8%) subjects were normoalbuminuric (MA-) for the duration of the study. At 5 years: 35 (11.4%) subjects had MA (MA+) and 30 (9.7%) subjects were normoalbuminuric but developed MA during subsequent follow-up annual assessments (future MA+). In the future MA+ group compared to the MA+ and MA- groups; GFR was higher (167 vs. 134 vs. 139 mL/min/1.73 m(2), P < 0.002); the prevalence of hyperfiltration (GFR >125 mL/min/1.73 m(2)) was greater (97 vs. 57 vs. 64%, P= 0.006) and HbA1c levels were higher (11.4 vs. 10.8 vs. 9.7%, P < 0.001). The probability (Cox Model) of having hyperfiltration at 5 years' duration was related to puberty (a 1.7-fold increased risk with puberty onset) and poor glycemic control (a 10% increased risk for a 1% increase in HbA1c). Comparing subjects with and without hyperfiltration, prior to the first GFR measurement no difference in ACR levels existed; however, after this time median ACR levels were significantly greater [1.2 (0.1-86.4) vs. 0.9 (0.1-71.6) mg/mmol, P= 0.003], independent of age and HbA1c levels. The probability of developing MA between 5 and 10 years' duration was associated with poor glycemic control (a 30% increased risk for a 1% increase in HbA1c) and higher GFR at 5 years (22% increased risk for a 10 mL/min/1.73 m(2) rise in GFR). CONCLUSION Glomerular hyperfiltration is associated with puberty and increasing ACR levels and is predictive of MA independent of HbA1c. This suggests that factors other than poor glycemic control may be involved in the pathogenesis of early diabetic nephropathy and early intervention with medical therapy to reduce GFR may be beneficial even before onset of MA.
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Watts A, Kehoe S, Luesley D. Community-based post-operative follow-up visit after major surgery for benign gynaecological conditions: a prospective study. J OBSTET GYNAECOL 2005; 17:468-71. [PMID: 15511924 DOI: 10.1080/01443619750112466] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
The time from surgery to discharge after major procedures for benign gynaecological conditions continues to fall. This small prospective study was undertaken to assess the postoperative problems encountered by patients after gynaecological surgery for a variety of benign disorders, and the potential of the 6-week surgical follow-up to be performed by the patient's family doctor rather than the hospital. The patients' and doctors' satisfaction with such care was determined. The study showed that follow-up in the community was acceptable to both patient and doctor. When problems arose after discharge most patients ( 50%) contacted their family doctor. At the 6-week visit few had physical problems, though most (58-100% depending on the Group) felt that a 6-week follow-up was required. Six-week postoperative follow-up by the family doctor is acceptable, and could permit more effective use of hospital specialists, though would increase the workload of family doctors.
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Lemaître V, Smith ME, Watts A. A review of oxygen-17 solid-state NMR of organic materials--towards biological applications. SOLID STATE NUCLEAR MAGNETIC RESONANCE 2004; 26:215-235. [PMID: 15388187 DOI: 10.1016/j.ssnmr.2004.04.004] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/08/2004] [Revised: 03/31/2004] [Indexed: 05/24/2023]
Abstract
17O solid state NMR of organic materials is developing rapidly. This article provides a snapshot of the current state of development of this field. The NMR techniques and enrichment protocols that are driving this progress are outlined. The (17)O parameters derived from solid-state NMR experiments are summarized and the structural sensitivity of the approach to effects such as hydrogen bonding highlighted. The prospects and challenges for (17)O solid-state NMR of biomolecules are discussed.
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Pike KJ, Lemaitre V, Kukol A, Anupõld T, Samoson A, Howes AP, Watts A, Smith ME, Dupree R. Solid-State 17O NMR of Amino Acids. J Phys Chem B 2004. [DOI: 10.1021/jp049958x] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Watts A, Green S. Valuing your skills. Nurs Manag (Harrow) 2004; 11:16-7. [PMID: 15148701] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/29/2023]
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Watts A, Green S. Levelling the playing field. Nurs Manag (Harrow) 2004; 11:12-4. [PMID: 15119084] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/29/2023]
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Watts A, Green S. Levelling the playing field Angela Watts and Simon Green discuss the harmonisation and standardisation of employment terms and conditions under Agenda for Change. Nurs Manag (Harrow) 2004; 11:12-14. [PMID: 27707029 DOI: 10.7748/nm.11.1.12.s11] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
ONE OF the principal changes brought about by introducing Agenda for Change (AfC) is the harmonisation and standardisation of NHS staff employment terms and conditions, such as the amount of annual leave, contracted hours and unsocial hours payments.
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Lemaitre V, Ali R, Kim CG, Watts A, Fischer WB. Interaction of amiloride and one of its derivatives with Vpu from HIV-1: a molecular dynamics simulation. FEBS Lett 2004; 563:75-81. [PMID: 15063726 DOI: 10.1016/s0014-5793(04)00251-0] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2004] [Revised: 02/26/2004] [Accepted: 03/02/2004] [Indexed: 11/24/2022]
Abstract
Vpu is an 81-residue membrane protein, with a single transmembrane segment that is encoded by HIV-1 and is involved in the enhancement of virion release via formation of an ion channel. Cyclohexamethylene amiloride (Hma) has been shown to inhibit ion channel activity. In the present 12-ns simulation study a putative binding site of Hma blockers in a pentameric model bundle built of parallel aligned helices of the first 32 residues of Vpu was found near Ser-23. Hma orientates along the channel axis with its alkyl ring pointing inside the pore, which leads to a blockage of the pore.
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Watts A, Green S. First steps of the journey:job evaluation for agenda for change. Nurs Manag (Harrow) 2004; 10:10-12. [PMID: 27707178 DOI: 10.7748/nm.10.10.10.s11] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
(JE) is probably the first Agenda for Change (AfC) activity that trusts will undertake: the starting point of a long journey to modernise pay and grading locally.
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Watts A, Green S. First steps of the journey: job evaluation for agenda for change. Nurs Manag (Harrow) 2004; 10:10-2. [PMID: 15038299] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/29/2023]
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Williamson PTF, Meier BH, Watts A. Structural and functional studies of the nicotinic acetylcholine receptor by solid-state NMR. EUROPEAN BIOPHYSICS JOURNAL: EBJ 2004; 33:247-54. [PMID: 14740198 DOI: 10.1007/s00249-003-0380-1] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/01/2003] [Revised: 11/17/2003] [Accepted: 11/20/2003] [Indexed: 12/01/2022]
Abstract
Over the last seven years, solid-state NMR has been widely employed to study structural and functional aspects of the nicotinic acetylcholine receptor. These studies have provided detailed structural information relating to both the ligand binding site and the transmembrane domain of the receptor. Studies of the ligand binding domain have elucidated the nature and the orientation of the pharmacophores responsible for the binding of the agonist acetylcholine within the agonist binding site. Analyses of small transmembrane fragments derived from the nicotinic acetylcholine receptor have also revealed the secondary structure and the orientation of these transmembrane domains. These experiments have expanded our understanding of the channel's structural properties and are providing an insight into how they might be modulated by the surrounding lipid environment. In this article we review the advances in solid-state NMR applied to the nicotinic acetylcholine receptor and compare the results with recent electron diffraction and X-ray crystallographic studies.
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