1
|
Iovinella M, Palmieri M, Papa S, Auciello C, Ventura R, Lombardo F, Race M, Lubritto C, di Cicco MR, Davis SJ, Trifuoggi M, Marano A, Ciniglia C. Biosorption of rare earth elements from luminophores by G. sulphuraria (Cyanidiophytina, Rhodophyta). Environ Res 2023; 239:117281. [PMID: 37827370 DOI: 10.1016/j.envres.2023.117281] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2023] [Revised: 09/28/2023] [Accepted: 09/29/2023] [Indexed: 10/14/2023]
Abstract
Lanthanides are indispensable constituents of modern technologies and are often challenging to acquire from natural resources. The demand for REEs is so high that there is a clear need to develop efficient and eco-friendly recycling methods. In the present study, freeze-dried biomass of the polyextremophile Galdieria sulphuraria was employed to recover REEs from spent fluorescent lamps (FL) luminophores by pretreating the freeze-dried biomass with an acid solution to favour ion exchange and enhance the binding sites on the cell surface available for the metal ions. Lanthanides were extracted from the luminophores using sulfuric acid solutions according to standardised procedures, and the effect of biosorbent dosage (0.5-5 mg/ml) and biosorption time (5-60 min) were evaluated. The content of individual REEs in the luminophores and the resulting algal biomass were determined using inductively coupled plasma mass spectrometry (ICP-MS). The most abundant REE in the luminophores was yttrium (287.42 mg/g dm, 91.60% of all REEs), followed by europium (20.98 mg/g, 6.69%); cerium, gadolinium, terbium and lanthanum was in trace. The best biosorption performances were achieved after 5 min and at the lowest biosorbent dosage (0.5 mg/mL). The highest total metal amount corresponded to 41.61 mg/g dried mass, and yttrium was the most adsorbed metal (34.59 mg/g dm, 82.88%), followed by cerium (4.01 mg/g); all other metals were less than 2 mg/g. The rapidity of the biosorption process and the low biosorbent dosage required confirmed this microalga as a promising material for creating an eco-sustainable protocol for recycling REEs.
Collapse
Affiliation(s)
- M Iovinella
- Department of Environmental, Biological and Pharmaceutical Sciences and Technologies, University of Campania "Luigi Vanvitelli", Via Vivaldi 43, 81100, Caserta, Italy; Department of Biology, University of York, Wentworth Way, YO10 5DD York, UK
| | - M Palmieri
- Department of Environmental, Biological and Pharmaceutical Sciences and Technologies, University of Campania "Luigi Vanvitelli", Via Vivaldi 43, 81100, Caserta, Italy
| | - S Papa
- Department of Environmental, Biological and Pharmaceutical Sciences and Technologies, University of Campania "Luigi Vanvitelli", Via Vivaldi 43, 81100, Caserta, Italy
| | - C Auciello
- Department of Environmental, Biological and Pharmaceutical Sciences and Technologies, University of Campania "Luigi Vanvitelli", Via Vivaldi 43, 81100, Caserta, Italy
| | - R Ventura
- Department of Environmental, Biological and Pharmaceutical Sciences and Technologies, University of Campania "Luigi Vanvitelli", Via Vivaldi 43, 81100, Caserta, Italy
| | - F Lombardo
- Department of Chemical Sciences, University of Naples Federico II, Via Cinthia, I-80126, Naples, Italy
| | - M Race
- Department of Civil and Mechanical Engineering, University of Cassino and Southern Lazio, Via Di Biasio, 43, 03043, Cassino, Italy
| | - C Lubritto
- Department of Environmental, Biological and Pharmaceutical Sciences and Technologies, University of Campania "Luigi Vanvitelli", Via Vivaldi 43, 81100, Caserta, Italy
| | - M R di Cicco
- Department of Environmental, Biological and Pharmaceutical Sciences and Technologies, University of Campania "Luigi Vanvitelli", Via Vivaldi 43, 81100, Caserta, Italy
| | - S J Davis
- Department of Biology, University of York, Wentworth Way, YO10 5DD York, UK
| | - M Trifuoggi
- Department of Chemical Sciences, University of Naples Federico II, Via Cinthia, I-80126, Naples, Italy
| | - A Marano
- Department of Chemical Sciences, University of Naples Federico II, Via Cinthia, I-80126, Naples, Italy
| | - C Ciniglia
- Department of Environmental, Biological and Pharmaceutical Sciences and Technologies, University of Campania "Luigi Vanvitelli", Via Vivaldi 43, 81100, Caserta, Italy; Department of Biology, University of York, Wentworth Way, YO10 5DD York, UK.
| |
Collapse
|
2
|
Davis SJ, Zhao Y, Yu TC, Maytin EV, Anand S, Hasan T, Pogue BW. Singlet Molecular Oxygen: from COIL Lasers to Photodynamic Cancer Therapy. J Phys Chem B 2023; 127:2289-2301. [PMID: 36893448 DOI: 10.1021/acs.jpcb.2c07330] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/11/2023]
Abstract
Translation of experimental techniques from one scientific discipline to another is often difficult but rewarding. Knowledge gained from the new area can lead to long lasting and fruitful collaborations with concomitant development of new ideas and studies. In this Review Article, we describe how early work on the chemically pumped atomic iodine laser (COIL) led to the development of a key diagnostic for a promising cancer treatment known as photodynamic therapy (PDT). The highly metastable excited state of molecular oxygen, a1Δg, also known as singlet oxygen, is the link between these disparate fields. It powers the COIL laser and is the active species that kills cancer cells during PDT. We describe the fundamentals of both COIL and PDT and trace the development path of an ultrasensitive dosimeter for singlet oxygen. The path from COIL lasers to cancer research was relatively long and required medical and engineering expertise from numerous collaborations. As we show below, the knowledge gained in the COIL research, combined with these extensive collaborations, has resulted in our being able to show a strong correlation between cancer cell death and the singlet oxygen measured during PDT treatments of mice. This progress is a key step in the eventual development of a singlet oxygen dosimeter that could be used to guide PDT treatments and improve outcomes.
Collapse
Affiliation(s)
- S J Davis
- Physical Sciences Inc., 20 New England Business Center, Andover, Massachusetts 01810, United States
| | - Y Zhao
- Physical Sciences Inc., 20 New England Business Center, Andover, Massachusetts 01810, United States
| | - T C Yu
- Physical Sciences Inc., 20 New England Business Center, Andover, Massachusetts 01810, United States
| | - E V Maytin
- Departments of Biomedical Engineering and Dermatology, Cleveland Clinic, 9500 Euclid Avenue, Cleveland, Ohio 44195, United States
| | - S Anand
- Departments of Biomedical Engineering and Dermatology, Cleveland Clinic, 9500 Euclid Avenue, Cleveland, Ohio 44195, United States
| | - T Hasan
- Wellman Center for Photomedicine, 40 Blossom Street, BAR 314A, Boston, Massachusetts 02114, United States
| | - B W Pogue
- Department of Medical Physics, Wisconsin Institutes for Medical Research, 1111 Highland Avenue, Madison, Wisconsin 53705, United States
| |
Collapse
|
3
|
Manfredi C, Amoruso AJ, Ciniglia C, Iovinella M, Palmieri M, Lubritto C, El Hassanin A, Davis SJ, Trifuoggi M. Selective biosorption of lanthanides onto Galdieria sulphuraria. Chemosphere 2023; 317:137818. [PMID: 36640971 DOI: 10.1016/j.chemosphere.2023.137818] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/13/2022] [Revised: 01/07/2023] [Accepted: 01/10/2023] [Indexed: 06/17/2023]
Abstract
The recovering of trivalent Lanthanides from aqueous solutions, by biosorption process onto Galdieria sulphuraria lifeless cells, was investigated. Potentiometry, UV-Vis, FTIR-ATR spectroscopy and SEM-EDS analysis were used. All the experiments were performed at 25 °C, in 0.5 M NaCl. Ln3+ biosorption is greater in the 5-6 pH range with values ranging from 80 μmol/g to 130 μmol/g (dry weight). The adsorbed Ln3+ ions can be recovered at higher acidity (pH<1) and the biosorbent can be reused. Specific molecular interactions between Ln3+ ions and the functional groups on G. sulphuraria surface were highlighted. Particularly, proteins are involved if Ln3+=Pr3+, Sm3+, Eu3+, Tb3+, Dy3+, Tm3+, while Ce3+, Ho3+, Er3+ form bonds with carbohydrates. Finally, both proteins and carbohydrates are involved if Gd3+ and Yb3+. A Surface Complexation approach, with a good graphical fitting to potentiometric experimental collected data, was used to describe the biosorption mechanism. This study could be of great applicative utility for removing of trivalent actinides, from waste aqueous solutions, by biosorption. As well known the lanthanides were used as model to simulate the chemical behaviour of actinides in the same oxidation state.
Collapse
Affiliation(s)
- C Manfredi
- Department of Chemical Sciences, University of Naples Federico II, Via Cintia, I-80126, Naples, Italy.
| | - A J Amoruso
- Department of Chemical Sciences, University of Naples Federico II, Via Cintia, I-80126, Naples, Italy
| | - C Ciniglia
- Department of Environmental, Biological and Pharmaceutical Sciences and Technologies, University of Caserta "L.Vanvitelli", Via Vivaldi 43, 81100, Caserta, Italy
| | - M Iovinella
- Department of Environmental, Biological and Pharmaceutical Sciences and Technologies, University of Caserta "L.Vanvitelli", Via Vivaldi 43, 81100, Caserta, Italy; Department of Biology, University of York, Wentworth Way, York, YO10 5DD, UK
| | - M Palmieri
- Department of Environmental, Biological and Pharmaceutical Sciences and Technologies, University of Caserta "L.Vanvitelli", Via Vivaldi 43, 81100, Caserta, Italy
| | - C Lubritto
- Department of Environmental, Biological and Pharmaceutical Sciences and Technologies, University of Caserta "L.Vanvitelli", Via Vivaldi 43, 81100, Caserta, Italy
| | - A El Hassanin
- Department of Chemical, Materials and Industrial Production Engineering, University of Naples Federico II, Italy
| | - S J Davis
- Department of Biology, University of York, Wentworth Way, York, YO10 5DD, UK; State Key Laboratory of Crop Stress Biology, School of Life Sciences, Henan University, Kaifeng, 475004, China
| | - M Trifuoggi
- Department of Chemical Sciences, University of Naples Federico II, Via Cintia, I-80126, Naples, Italy
| |
Collapse
|
4
|
Davis SJ, Scott LL, Ordemann G, Philpo A, Cohn J, Pierce-Shimomura JT. Putative calcium-binding domains of the Caenorhabditis elegans BK channel are dispensable for intoxication and ethanol activation. Genes Brain Behav 2016; 14:454-65. [PMID: 26113050 DOI: 10.1111/gbb.12229] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/17/2014] [Revised: 06/16/2015] [Accepted: 06/22/2015] [Indexed: 01/17/2023]
Abstract
Alcohol modulates the highly conserved, voltage- and calcium-activated potassium (BK) channel, which contributes to alcohol-mediated behaviors in species from worms to humans. Previous studies have shown that the calcium-sensitive domains, RCK1 and the Ca(2+) bowl, are required for ethanol activation of the mammalian BK channel in vitro. In the nematode Caenorhabditis elegans, ethanol activates the BK channel in vivo, and deletion of the worm BK channel, SLO-1, confers strong resistance to intoxication. To determine if the conserved RCK1 and calcium bowl domains were also critical for intoxication and basal BK channel-dependent behaviors in C. elegans, we generated transgenic worms that express mutated SLO-1 channels predicted to have the RCK1, Ca(2+) bowl or both domains rendered insensitive to calcium. As expected, mutating these domains inhibited basal function of SLO-1 in vivo as neck and body curvature of these mutants mimicked that of the BK null mutant. Unexpectedly, however, mutating these domains singly or together in SLO-1 had no effect on intoxication in C. elegans. Consistent with these behavioral results, we found that ethanol activated the SLO-1 channel in vitro with or without these domains. By contrast, in agreement with previous in vitro findings, C. elegans harboring a human BK channel with mutated calcium-sensing domains displayed resistance to intoxication. Thus, for the worm SLO-1 channel, the putative calcium-sensitive domains are critical for basal in vivo function but unnecessary for in vivo ethanol action.
Collapse
Affiliation(s)
- S J Davis
- Waggoner Center for Alcohol and Addiction Research, Institute for Neuroscience, Center for Learning and Memory, Center for Brain, Behavior and Evolution, and Department of Neuroscience, The University of Texas at Austin, Austin, TX, USA
| | - L L Scott
- Waggoner Center for Alcohol and Addiction Research, Institute for Neuroscience, Center for Learning and Memory, Center for Brain, Behavior and Evolution, and Department of Neuroscience, The University of Texas at Austin, Austin, TX, USA
| | - G Ordemann
- Waggoner Center for Alcohol and Addiction Research, Institute for Neuroscience, Center for Learning and Memory, Center for Brain, Behavior and Evolution, and Department of Neuroscience, The University of Texas at Austin, Austin, TX, USA
| | - A Philpo
- Waggoner Center for Alcohol and Addiction Research, Institute for Neuroscience, Center for Learning and Memory, Center for Brain, Behavior and Evolution, and Department of Neuroscience, The University of Texas at Austin, Austin, TX, USA
| | - J Cohn
- Waggoner Center for Alcohol and Addiction Research, Institute for Neuroscience, Center for Learning and Memory, Center for Brain, Behavior and Evolution, and Department of Neuroscience, The University of Texas at Austin, Austin, TX, USA
| | - J T Pierce-Shimomura
- Waggoner Center for Alcohol and Addiction Research, Institute for Neuroscience, Center for Learning and Memory, Center for Brain, Behavior and Evolution, and Department of Neuroscience, The University of Texas at Austin, Austin, TX, USA
| |
Collapse
|
5
|
Abstract
Group 1 salts were compared with quaternary ammonium chlorides for their ability to form deep eutectic solvents and it was found that while some formed liquids the sodium ions caused the liquids to become structured and increased their viscosity.
Collapse
Affiliation(s)
- A. P. Abbott
- Department of Chemistry
- University of Leicester
- Leicester LE1 7RH
- UK
| | - C. D'Agostino
- Department of Chemical Engineering and Biotechnology
- University of Cambridge
- UK
| | - S. J. Davis
- Department of Chemistry
- University of Leicester
- Leicester LE1 7RH
- UK
| | - L. F. Gladden
- Department of Chemical Engineering and Biotechnology
- University of Cambridge
- UK
| | - M. D. Mantle
- Department of Chemical Engineering and Biotechnology
- University of Cambridge
- UK
| |
Collapse
|
6
|
Rawlins WT, Galbally-Kinney KL, Davis SJ, Hoskinson AR, Hopwood JA, Heaven MC. Optically pumped microplasma rare gas laser. Opt Express 2015; 23:4804-4813. [PMID: 25836515 DOI: 10.1364/oe.23.004804] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The optically pumped rare-gas metastable laser is a chemically inert analogue to three-state optically pumped alkali laser systems. The concept requires efficient generation of electronically excited metastable atoms in a continuous-wave (CW) electric discharge in flowing gas mixtures near atmospheric pressure. We have observed CW optical gain and laser oscillation at 912.3 nm using a linear micro-discharge array to generate metastable Ar(4s, 1s(5)) atoms at atmospheric pressure. We observed the optical excitation of the 1s(5) → 2p(9) transition at 811.5 nm and the corresponding fluorescence, optical gain and laser oscillation on the 2p(10) ↔ 1s(5) transition at 912.3 nm, following 2p(9)→2p(10) collisional energy transfer. A steady-state kinetics model indicates efficient collisional coupling within the Ar(4s) manifold.
Collapse
|
7
|
Abstract
Age-related macular degeneration (AMD) can have devastating effects on vision, especially in its neovascular form. In the last decade, the use of intravitreal pharmacotherapy targeted to vascular endothelial growth factor (VEGF) has significantly improved the visual outcomes in patients with neovascular AMD. Although we have become accustomed to these unprecedented improvement outcomes, maintaining good visual results with anti-VEGF therapy requires tremendous effort, time and cost, typically involving monthly clinic visits and intravitreal injections. The introduction of aflibercept, an anti-VEGF drug that targets all isoforms of VEGF as well as placenta growth factor, has shown promise throughout recent clinical trials as an equally effective treatment for neovascular AMD that requires less frequent dosing than either ranibizumab or bevacizumab. Based on clinical trial results, the U.S. Food and Drug Administration approved aflibercept in November 2011 for use in neovascular AMD, giving patients the hope of alleviating some of the burden associated with treatment.
Collapse
Affiliation(s)
- E A Verner-Cole
- Oregon Health and Science University, Department of Ophthalmology, Portland, OR, USA
| | | | | |
Collapse
|
8
|
Davis SJ, Simpson KJ, Campbell IG, Gorringe KL. Integrated genomic analysis and functional characterisation of novel oncogenes in ovarian cancer. Hered Cancer Clin Pract 2012. [PMCID: PMC3327270 DOI: 10.1186/1897-4287-10-s2-a81] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022] Open
|
9
|
Readle JD, Verdeyen JT, Eden JG, Davis SJ, Gabally-Kinney KL, Rawlins WT, Kessler WJ. Cs 894.3 nm laser pumped by photoassociation of Cs-Kr pairs: excitation of the Cs D(2) blue and red satellites. Opt Lett 2009; 34:3638-3640. [PMID: 19953146 DOI: 10.1364/ol.34.003638] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Lasing on the D(1) transition (6P1/22-->6S1/22) of Cs has been observed by photoassociating Cs-Kr atomic pairs with a tunable, pulsed dye laser. Pumping of the blue or red satellites of the Cs D(2) line (62P3/2<==>62S1/2), peaking at approximately 841.1 nm and approximately 853 nm (respectively) in Cs/Kr/C(2)H(6) gas mixtures, provides a photodissociation laser in which the CsKr excimer parent molecule is not, at any point in the pumping process, in a bound electronic state. Relative to the absorbed pump pulse energy, laser slope efficiencies greater than or approximately 5% have been measured when the Cs number density is in the range of 5x10(14)-1.5x10(15) cm(-3) and the pump wavelength is 841.1 nm. Direct photoexcitation of the Cs 6P3/22 state at 852.1 nm under these conditions is a less efficient pathway for pumping the 894.3 nm laser, presumably as a result of competing nonlinear optical processes such as 1+2 resonantly enhanced multiphoton ionization of the alkali atom.
Collapse
Affiliation(s)
- J D Readle
- Laboratory for Optical Physics and Engineering, Department of Electrical and Computer Engineering, University of Illinois, Urbana, Illinois 61801, USA.
| | | | | | | | | | | | | |
Collapse
|
10
|
Robertson SL, Davis SJ, Sneed Z, Koch DS, Boston Q. Competency Issues for Alcohol/Other Drug Abuse Counselors. Alcoholism Treatment Quarterly 2009. [DOI: 10.1080/07347320903014347] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
|
11
|
Abstract
A recent study shows that a small GTPase, LIF1, helps to coordinate the plant circadian clock with the daily light-dark cycle.
Collapse
Affiliation(s)
- E Kolmos
- Max Planck Institute for Plant Breeding Research, Carl-von-Linné-Weg 10, D-50829 Cologne, Germany
| | | |
Collapse
|
12
|
Rawlins WT, Oakes DB, Davis SJ. Hyperspectral Infrared Imaging of HF( v, J) Chemiluminescence and Gain in Chemically Reacting Flowfields. J Phys Chem A 2007; 111:6860-9. [PMID: 17518458 DOI: 10.1021/jp071786r] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
This paper presents results from investigations of chemically reacting flowfields and optical gain profiles in HF chemical laser media by infrared hyperspectral imaging. Subsonic and supersonic chemiluminescent F+H2 reacting flowfields, produced in high-fluence microwave-driven reactors, were imaged at a series of wavelengths, 2.6-3.1 microm, by a low-order, spectrally scanning Fabry-Perot interferometer mated to an infrared camera. The resulting hyperspectral data cubes define the spectral and spatial distributions of the emission. Spectrally resolved images at high spatial resolution were processed to determine spatial distributions of the excited-state concentrations of the product HF(v, J) molecules, as well as spatial distributions of small-signal gain on specific laser transitions. Additional high-resolution Fourier transform spectroscopy and spectral fitting analysis determined detailed excited-state distributions in the reacting flowfields. The measurements showed that energetic HF(v, J) state distributions were generated by both the supersonic and fast-flow subsonic mixing schemes. In particular, the subsonic reactor produced a spatially distributed field of inverted, near-nascent state populations, with small-signal gains near 2-3%/cm.
Collapse
Affiliation(s)
- W T Rawlins
- Physical Sciences Inc., 20 New England Business Center, Andover, Massachusetts 01810, USA.
| | | | | |
Collapse
|
13
|
Abstract
AbstractWe report a case of Miller Fisher syndrome presenting in an ENT setting. The referral was made on the basis of worsening nasal regurgitation following Campylobacter jejuni enteritis. The aim of this report is not to add to the recorded instances of Miller Fisher syndrome, but to help raise the level of its awareness amongst otolaryngologists. Emphasis is placed on the mode of presentation and management issues, as early diagnosis is crucial and confers a favourable prognosis. In that respect, we consider this case noteworthy and instructive.
Collapse
Affiliation(s)
- S J Davis
- Department of Otorhinolaryngology, Queen Alexandra Hospital, Portsmouth, UK.
| | | | | | | |
Collapse
|
14
|
Aricescu AR, Assenberg R, Bill RM, Busso D, Chang VT, Davis SJ, Dubrovsky A, Gustafsson L, Hedfalk K, Heinemann U, Jones IM, Ksiazek D, Lang C, Maskos K, Messerschmidt A, Macieira S, Peleg Y, Perrakis A, Poterszman A, Schneider G, Sixma TK, Sussman JL, Sutton G, Tarboureich N, Zeev-Ben-Mordehai T, Jones EY. Eukaryotic expression: developments for structural proteomics. Acta Crystallogr D Biol Crystallogr 2006; 62:1114-24. [PMID: 17001089 PMCID: PMC7161643 DOI: 10.1107/s0907444906029805] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 03/24/2006] [Accepted: 07/31/2006] [Indexed: 12/02/2022]
Abstract
The production of sufficient quantities of protein is an essential prelude to a structure determination, but for many viral and human proteins this cannot be achieved using prokaryotic expression systems. Groups in the Structural Proteomics In Europe (SPINE) consortium have developed and implemented high‐throughput (HTP) methodologies for cloning, expression screening and protein production in eukaryotic systems. Studies focused on three systems: yeast (Pichia pastoris and Saccharomyces cerevisiae), baculovirus‐infected insect cells and transient expression in mammalian cells. Suitable vectors for HTP cloning are described and results from their use in expression screening and protein‐production pipelines are reported. Strategies for co‐expression, selenomethionine labelling (in all three eukaryotic systems) and control of glycosylation (for secreted proteins in mammalian cells) are assessed.
Collapse
Affiliation(s)
- A R Aricescu
- Division of Structural Biology and Oxford Protein Production Facility, Wellcome Trust Centre for Human Genetics, Oxford, England
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
15
|
Abstract
Background: The implementation of the European working time directive has led to an increase in cross-speciality out-of-hours cover. This survey illustrates ENT out-of-hours cover arrangements and assesses the implications for senior house officers (SHOs) responsible for managing emergencies.Methods: A telephone survey of 100 ENT departments was conducted, asking the on-call SHO about departmental structure, on-call rota design, their previous ENT experience, access to SHO training and their confidence in managing emergencies.Results: 44 per cent of departments used only ENT SHOs on the on-call rota. 73 per cent always had an ENT middle grade on call. In 60 per cent of hospitals, the ENT consultant was sometimes on call with only a non-ENT SHO. At the time of the study, 5 per cent of SHOs had no ENT experience, no access to training, were not confident in managing simple emergencies and were on-call without middle-grade cover.Conclusion: The current junior on-call structure for ENT has implications for patient management.
Collapse
Affiliation(s)
- S J Davis
- ENT Department, Queen Alexandra Hospital, Portsmouth, UK.
| | | |
Collapse
|
16
|
James ES, Harney S, Wordsworth BP, Cookson WOCM, Davis SJ, Moffatt MF. PDCD1: a tissue-specific susceptibility locus for inherited inflammatory disorders. Genes Immun 2005; 6:430-7. [PMID: 15959535 DOI: 10.1038/sj.gene.6364223] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Variation in genes encoding costimulatory molecules expressed on lymphocytes has been expected to contribute to the genetic component of inflammatory disease, but only the gene encoding the inhibitory protein, CTLA-4, seems consistently to confer disease susceptibility. Studies in murine models implicate the inhibitory product of the pd1 gene, programmed death-1, in the maintenance of peripheral tolerance to self-antigens. We identify 22 single-nucleotide polymorphisms (SNPs) in the equivalent human gene, PDCD1, a number of which show significant associations with the specific immunoglobulin E response to grass allergens in atopic individuals. Stepwise analyses indicate that four of the disease-associated SNPs have independent effects. The two most common haplotypes show positive and negative associations but rarer haplotypes are also likely to be of influence. In a case-control study, multiple regression analysis of genotypic data implies that PDCD1 also confers susceptibility to rheumatoid arthritis. Along with work linking PDCD1 with susceptibility to another autoimmune condition, systemic lupus erythematosus, our data identify PDCD1 as a second immunomodulatory gene with pleiotropic effects in human disease. Genes encoding negative regulators may generally confer a significant fraction of the genetic risk associated with inherited inflammatory disorders.
Collapse
Affiliation(s)
- E S James
- Nuffield Department of Clinical Medicine, The University of Oxford, John Radcliffe Hospital, Headington, Oxford, UK
| | | | | | | | | | | |
Collapse
|
17
|
Brown J, Walter TS, Carter L, Abrescia NGA, Aricescu AR, Batuwangala TD, Bird LE, Brown N, Chamberlain PP, Davis SJ, Dubinina E, Endicott J, Fennelly JA, Gilbert RJC, Harkiolaki M, Hon WC, Kimberley F, Love CA, Mancini EJ, Manso-Sancho R, Nichols CE, Robinson RA, Sutton GC, Schueller N, Sleeman MC, Stewart-Jones GB, Vuong M, Welburn J, Zhang Z, Stammers DK, Owens RJ, Jones EY, Harlos K, Stuart DI. A procedure for setting up high-throughput nanolitre crystallization experiments. II. Crystallization results. J Appl Crystallogr 2003. [DOI: 10.1107/s0021889803002012] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
An initial tranche of results from day-to-day use of a robotic system for setting up 100 nl-scale vapour-diffusion sitting-drop protein crystallizations has been surveyed. The database of over 50 unrelated samples represents a snapshot of projects currently at the stage of crystallization trials in Oxford research groups and as such encompasses a broad range of proteins. The results indicate that the nanolitre-scale methodology consistently identifies more crystallization conditions than traditional hand-pipetting-style methods; however, in a number of cases successful scale-up is then problematic. Crystals grown in the initial 100 nl-scale drops have in the majority of cases allowed useful characterization of X-ray diffraction, either in-house or at synchrotron beamlines. For a significant number of projects, full X-ray diffraction data sets have been collected to 3 Å resolution or better (either in-house or at the synchrotron) from crystals grown at the 100 nl scale. To date, five structures have been determined by molecular replacement directly from such data and a further three from scale-up of conditions established at the nanolitre scale.
Collapse
|
18
|
Affiliation(s)
- Anatoly V. Komissarov
- Department of Chemistry, Emory University, Atlanta, Georgia 30322, Air Force Research Laboratory, Directed Energy Directorate, Kirtland AFB, New Mexico 87118, and Physical Sciences, Inc., 20 New England Business Center, Andover, Massachusetts 01810
| | - Gerald C. Manke
- Department of Chemistry, Emory University, Atlanta, Georgia 30322, Air Force Research Laboratory, Directed Energy Directorate, Kirtland AFB, New Mexico 87118, and Physical Sciences, Inc., 20 New England Business Center, Andover, Massachusetts 01810
| | - S. J. Davis
- Department of Chemistry, Emory University, Atlanta, Georgia 30322, Air Force Research Laboratory, Directed Energy Directorate, Kirtland AFB, New Mexico 87118, and Physical Sciences, Inc., 20 New England Business Center, Andover, Massachusetts 01810
| | - Michael C. Heaven
- Department of Chemistry, Emory University, Atlanta, Georgia 30322, Air Force Research Laboratory, Directed Energy Directorate, Kirtland AFB, New Mexico 87118, and Physical Sciences, Inc., 20 New England Business Center, Andover, Massachusetts 01810
| |
Collapse
|
19
|
Davis SJ, Mulhall PA, Bachman M, Kessler WJ, Keating PB. Measurements of Pressure-Broadening Coefficients for the F‘ = 3 ← F‘ ‘ = 4 Hyperfine Line of the 2P1/2 ← 2P3/2 Transition in Atomic Iodine. J Phys Chem A 2002. [DOI: 10.1021/jp014690k] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
|
20
|
Davis SJ, Woodward AM. Excitation of iodine fluoride(B3.PI.(0+)) by metastable oxygen. 1. Studies involving iodine fluoride (X,v). ACTA ACUST UNITED AC 2002. [DOI: 10.1021/j100165a008] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
|
21
|
Abstract
Phytochromes comprise a principal family of red/far-red light sensors in plants. Although phytochromes were thought originally to be confined to photosynthetic organisms, we have recently detected phytochrome-like proteins in two heterotrophic eubacteria, Deinococcus radiodurans and Pseudomonas aeruginosa. Here we show that these form part of a widespread family of bacteriophytochromes (BphPs) with homology to two-component sensor histidine kinases. Whereas plant phytochromes use phytochromobilin as the chromophore, BphPs assemble with biliverdin, an immediate breakdown product of haem, to generate photochromic kinases that are modulated by red and far-red light. In some cases, a unique haem oxygenase responsible for the synthesis of biliverdin is part of the BphP operon. Co-expression of this oxygenase with a BphP apoprotein and a haem source is sufficient to assemble holo-BphP in vivo. Both their presence in many diverse bacteria and their simplified assembly with biliverdin suggest that BphPs are the progenitors of phytochrome-type photoreceptors.
Collapse
Affiliation(s)
- S H Bhoo
- Cellular and Molecular Biology Program, Department of Horticulture, University of Wisconsin-Madison, 1575 Linden Drive, Madison, Wisconsin 53706, USA
| | | | | | | | | |
Collapse
|
22
|
Abstract
According to the two-signal model of T cell activation, costimulatory molecules augment T cell receptor (TCR) signaling, whereas adhesion molecules enhance TCR-MHC-peptide recognition. The structure and binding properties of CD28 imply that it may perform both functions, blurring the distinction between adhesion and costimulatory molecules. Our results show that CD28 on naïve T cells does not support adhesion and has little or no capacity for directly enhancing TCR-MHC-peptide interactions. Instead of being dependent on costimulatory signaling, we propose that a key function of the immunological synapse is to generate a cellular microenvironment that favors the interactions of potent secondary signaling molecules, such as CD28.
Collapse
Affiliation(s)
- S K Bromley
- Department of Pathology and Immunology, Washington University School of Medicine, 660 S. Euclid Ave, St. Louis MO, USA
| | | | | | | | | | | | | | | |
Collapse
|
23
|
Abstract
The CD2 subset of the immunoglobulin superfamily consists of a rapidly expanding family of leukocyte cell surface receptors, at least five of which (CD2, CD48, CD58, CD150, and CD244) are involved in lymphocyte activation as either receptors or ligands. Completion of the draft sequence of the human genome offers the possibility of systematically identifying the full set of proteins and interactions of this important family. Here we describe the identification and characterization of the first new member of the subset, CD2F-10, found exclusively by genome searching.
Collapse
Affiliation(s)
- J A Fennelly
- Molecular Sciences Division, Nuffield Department of Clinical Medicine, The University of Oxford, Oxford, OX3 9DU, UK
| | | | | | | |
Collapse
|
24
|
Davis SJ, Bhoo SH, Durski AM, Walker JM, Vierstra RD. The heme-oxygenase family required for phytochrome chromophore biosynthesis is necessary for proper photomorphogenesis in higher plants. Plant Physiol 2001; 126:656-69. [PMID: 11402195 PMCID: PMC111157 DOI: 10.1104/pp.126.2.656] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
The committed step in the biosynthesis of the phytochrome chromophore phytochromobilin involves the oxidative cleavage of heme by a heme oxygenase (HO) to form biliverdin IXalpha. Through positional cloning of the photomorphogenic mutant hy1, the Arabidopsis HO (designated AtHO1) responsible for much of phytochromobilin synthesis recently was identified. Using the AtHO1 sequence, we identified families of HO genes in a number of plants that cluster into two subfamilies (HO1- and HO2-like). The tomato (Lycopersicon esculentum) yg-2 and Nicotiana plumbaginifolia pew1 photomorphogenic mutants are defective in specific HO genes. Phenotypic analysis of a T-DNA insertion mutant of Arabidopsis HO2 revealed that the second HO subfamily also contributes to phytochromobilin synthesis. Homozygous ho2-1 plants show decreased chlorophyll accumulation, reduced growth rate, accelerated flowering time, and reduced de-etiolation. A mixture of apo- and holo-phyA was detected in etiolated ho2-1 seedlings, suggesting that phytochromobilin is limiting in this mutant, even in the presence of functional AtHO1. The patterns of Arabidopsis HO1 and HO2 expression suggest that the products of both genes overlap temporally and spatially. Taken together, the family of HOs is important for phytochrome-mediated development in a number of plants and that each family member may uniquely contribute to the phytochromobilin pool needed to assemble holo-phytochromes.
Collapse
Affiliation(s)
- S J Davis
- Laboratory of Genetics, Cellular and Molecular Biology Program, and the Department of Horticulture, University of Wisconsin, 1575 Linden Drive, Madison, Wisconsin 53706, USA
| | | | | | | | | |
Collapse
|
25
|
|
26
|
Davis SJ, Ikemizu S, Collins AV, Fennelly JA, Harlos K, Jones EY, Stuart DI. Crystallization and functional analysis of a soluble deglycosylated form of the human costimulatory molecule B7-1. Acta Crystallogr D Biol Crystallogr 2001; 57:605-8. [PMID: 11264596 DOI: 10.1107/s0907444901001895] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2000] [Accepted: 01/26/2001] [Indexed: 11/10/2022]
Abstract
The interactions of B7-1 with CD28 and CTLA-4 modulate the course of human immune responses, making B7-1 an important target for developing structure-based therapeutics. B7-1 is, however, one of the most heavily glycosylated proteins found at the leukocyte cell surface, complicating the structural analysis of this molecule. Methods for the production, crystallization and selenomethionine labelling of a soluble deglycosylated form of this molecule are described. The protein readily forms both tetragonal plate and bipyramidal crystals belonging to space groups I4(1)22, with unit-cell parameters a = b = 56.9, c = 298.7 A, and P4(1)22 (or P4(3)22), with unit-cell parameters a = b = 89.0, c = 261.9 A, respectively. The I4(1)22 and primitive crystal forms diffract to 2.7 and 3.5 A, respectively. Surface plasmon resonance-based assays indicate that the ligand-binding properties of sB7-1 are unaffected by deglycosylation. Since none of the methods relied on any special structural properties of sB7-1, it is proposed that this novel combination of procedures could in principle be adapted to the systematic analysis of many other glycoproteins of structural or functional interest.
Collapse
Affiliation(s)
- S J Davis
- Nuffield Department of Clinical Medicine, The University of Oxford, John Radcliffe Hospital, Headington, Oxford OX3 9DU, England.
| | | | | | | | | | | | | |
Collapse
|
27
|
Stamper CC, Zhang Y, Tobin JF, Erbe DV, Ikemizu S, Davis SJ, Stahl ML, Seehra J, Somers WS, Mosyak L. Crystal structure of the B7-1/CTLA-4 complex that inhibits human immune responses. Nature 2001; 410:608-11. [PMID: 11279502 DOI: 10.1038/35069118] [Citation(s) in RCA: 344] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Optimal immune responses require both an antigen-specific and a co-stimulatory signal. The shared ligands B7-1 and B7-2 on antigen-presenting cells deliver the co-stimulatory signal through CD28 and CTLA-4 on T cells. Signalling through CD28 augments the T-cell response, whereas CTLA-4 signalling attenuates it. Numerous animal studies and recent clinical trials indicate that manipulating these interactions holds considerable promise for immunotherapy. With the consequences of these signals well established, and details of the downstream signalling events emerging, understanding the molecular nature of these extracellular interactions becomes crucial. Here we report the crystal structure of the human CTLA-4/B7-1 co-stimulatory complex at 3.0 A resolution. In contrast to other interacting cell-surface molecules, the relatively small CTLA-4/B7-1 binding interface exhibits an unusually high degree of shape complementarity. CTLA-4 forms homodimers through a newly defined interface of highly conserved residues. In the crystal lattice, CTLA-4 and B7-1 pack in a strikingly periodic arrangement in which bivalent CTLA-4 homodimers bridge bivalent B7-1 homodimers. This zipper-like oligomerization provides the structural basis for forming unusually stable signalling complexes at the T-cell surface, underscoring the importance of potent inhibitory signalling in human immune responses.
Collapse
Affiliation(s)
- C C Stamper
- Departments of Biological Chemistry and Musculoskeletal Sciences, Wyeth Research, 87 Cambridge Park Drive, Cambridge, Massachusetts 02140, USA
| | | | | | | | | | | | | | | | | | | |
Collapse
|
28
|
Pellicci DG, Kortt AA, Sparrow LG, Hudson PJ, Sorensen HV, Davis SJ, Classon BJ. Expression and purification of antigenically active soluble derivatives of the heterodimeric and homodimeric forms of the mouse CD8 lymphocyte membrane glycoprotein. J Immunol Methods 2000; 246:149-63. [PMID: 11121556 DOI: 10.1016/s0022-1759(00)00280-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The T lymphocyte membrane glycoprotein CD8 enhances antigen recognition by class I-restricted T cells. There are two naturally occurring forms of CD8, an alphabeta heterodimer expressed by the majority of CD8(+) T cells, and a less abundant alphaalpha homodimer found on specialised T cell subsets. An expression strategy was developed for production of soluble CD8alphaalpha and CD8alphabeta extracellular domains for use in ligand binding studies. Mouse CD8alpha was expressed autonomously as a homodimer at 10 mg/l in mammalian fibroblasts, but CD8beta was not expressed at significant levels in the absence of CD8alpha. Co-expression with CD8alpha led to significant enhancement in the level of CD8beta expression, which was secreted as a non-covalent heterodimer at 3 mg/l with CD8alpha. Despite the marked increase of CD8beta expression in the presence of CD8alpha, an excess of soluble CD8alphaalpha homodimer was also present in the supernatant of co-expressing cell clones. In order to resolve the CD8alphaalpha homodimer from the CD8alphabeta heterodimer, affinity chromatographic techniques specific for the CD8beta subunit were employed. Purification procedures requiring elution from affinity matrices at low pH led to substantial losses in the total antigenic activity and partial subunit dissociation of the soluble CD8alphabeta heterodimer. The inclusion of a hexahistidine tag at the C-terminus of CD8beta enabled affinity purification of soluble CD8alphabeta (and sCD8alphaalpha) under neutral conditions, yielding recombinant protein with the correct stoichiometry and full antigenic activity. This method may prove useful for production of other soluble recombinant heterodimeric receptor proteins whose antigenicity is affected by denaturation during immunoaffinity purification.
Collapse
Affiliation(s)
- D G Pellicci
- Department of Pathology and Immunology, Monash Medical School, Commercial Road, Vic. 3181, Prahran, Australia
| | | | | | | | | | | | | |
Collapse
|
29
|
Abstract
The recent discovery of phytochrome-like photoreceptors, collectively called bacteriophytochromes, in a number of bacteria has greatly expanded our understanding of the origins and modes of action of phytochromes in higher plants. These primitive receptors contain an N-terminal domain homologous to the chromophore-binding pocket of phytochromes, and like phytochromes, they bind a variety of bilins to generate photochromic holoproteins. Following the chromophore pocket is a domain similar to two-component histidine kinases, suggesting that these bacterial photoreceptors function in phosphorelay cascades that respond to the light environment. Their organization and distribution support the views that higher-plant phytochromes evolved from a cyanobacterial precursor and that they act as light-regulated kinases. With the ability to exploit bacterial genetics, these bacteriophytochromes now offer simple models to help unravel the biochemical and biophysical events that initiate phytochrome signal transmission.
Collapse
Affiliation(s)
- R D Vierstra
- Cellular and Molecular Biology and Genetics Programs and the Department of Horticulture, University of Wisconsin-Madison, 1575 Linden Drive Madison, WI 53706, USA.
| | | |
Collapse
|
30
|
Haas TL, Milkiewicz M, Davis SJ, Zhou AL, Egginton S, Brown MD, Madri JA, Hudlicka O. Matrix metalloproteinase activity is required for activity-induced angiogenesis in rat skeletal muscle. Am J Physiol Heart Circ Physiol 2000; 279:H1540-7. [PMID: 11009439 DOI: 10.1152/ajpheart.2000.279.4.h1540] [Citation(s) in RCA: 138] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Proteolysis of the capillary basement membrane is a hallmark of inflammation-mediated angiogenesis, but it is undetermined whether proteolysis plays a critical role in the process of activity-induced angiogenesis. Matrix metalloproteinases (MMPs) constitute the major class of proteases responsible for degradation of basement membrane proteins. We observed significant elevations of mRNA and protein levels of both MMP-2 and membrane type 1 (MT1)-MMP (2.9 +/- 0.7- and 1.5 +/- 0.1-fold above control, respectively) after 3 days of chronic electrical stimulation of rat skeletal muscle. Inhibition of MMP activity via the inhibitor GM-6001 prevented the growth of new capillaries as assessed by the capillary-to-fiber ratio (1.34 +/- 0.08 in GM-6001-treated muscles compared with 1.69 +/- 0.03 in control 7-day-stimulated muscles). This inhibition correlated with a significant reduction in the number of capillaries with observable breaks in the basement membrane, as assessed by electron microscopy (0.27 +/- 0.27% in GM-6001-treated muscles compared with 3.72 +/- 0.65% in control stimulated muscles). Proliferation of capillary-associated cells was significantly elevated by 2 days and remained elevated throughout 14 days of stimulation. Capillary-associated cell proliferation during muscle stimulation was not affected by MMP inhibition (80.3 +/- 9.3 nuclei in control and 63.5 +/- 8.5 nuclei in GM-6001-treated animals). We conclude that MMP proteolysis of capillary basement membrane proteins is a critical component of physiological angiogenesis, and we postulate that capillary-associated proliferation precedes and occurs independently of endothelial cell sprout formation.
Collapse
Affiliation(s)
- T L Haas
- Department of Pathology, Yale University, New Haven, Connecticut 06515, USA.
| | | | | | | | | | | | | | | |
Collapse
|
31
|
Mavaddat N, Mason DW, Atkinson PD, Evans EJ, Gilbert RJ, Stuart DI, Fennelly JA, Barclay AN, Davis SJ, Brown MH. Signaling lymphocytic activation molecule (CDw150) is homophilic but self-associates with very low affinity. J Biol Chem 2000; 275:28100-9. [PMID: 10831600 DOI: 10.1074/jbc.m004117200] [Citation(s) in RCA: 108] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Signaling lymphocytic activating molecule ((SLAM) CDw150) is a glycoprotein that belongs to the CD2 subset of the immunoglobulin superfamily and is expressed on the surface of activated T- and B-cells. It has been proposed that SLAM is homophilic and required for bidirectional signaling during T- and B-cell activation. Previous work has suggested that the affinity of SLAM self-association might be unusually high, undermining the concept that protein interactions mediating transient cell-cell contacts, such as those involving leukocytes, have to be weak in order that such contacts are readily reversible. Using surface plasmon resonance-based methods and analytical ultracentrifugation (AUC), we confirm that SLAM is homophilic. However, we also establish a new theoretical treatment of surface plasmon resonance-derived homophilic binding data, which indicates that SLAM-SLAM interactions (solution K(d) approximately 200 micrometer) are in fact considerably weaker than most other well characterized protein-protein interactions at the cell surface (solution K(d) approximately 0.4-20 micrometer), a conclusion that is supported by the AUC analysis. Whereas further analysis of the AUC data imply that SLAM could form "head to head" dimers spanning adjacent cells, the very low affinity raises important questions regarding the physiological role and/or properties of such interactions.
Collapse
Affiliation(s)
- N Mavaddat
- Sir William Dunn School of Pathology, The University of Oxford, Oxford OX1 3RE, United Kingdom
| | | | | | | | | | | | | | | | | | | |
Collapse
|
32
|
Vorup-Jensen T, Petersen SV, Hansen AG, Poulsen K, Schwaeble W, Sim RB, Reid KB, Davis SJ, Thiel S, Jensenius JC. Distinct pathways of mannan-binding lectin (MBL)- and C1-complex autoactivation revealed by reconstitution of MBL with recombinant MBL-associated serine protease-2. J Immunol 2000; 165:2093-100. [PMID: 10925294 DOI: 10.4049/jimmunol.165.4.2093] [Citation(s) in RCA: 147] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Mannan-binding lectin (MBL) plays a pivotal role in innate immunity by activating complement after binding carbohydrate moieties on pathogenic bacteria and viruses. Structural similarities shared by MBL and C1 complexes and by the MBL- and C1q-associated serine proteases, MBL-associated serine protease (MASP)-1 and MASP-2, and C1r and C1s, respectively, have led to the expectation that the pathways of complement activation by MBL and C1 complexes are likely to be very similar. We have expressed rMASP-2 and show that, whereas C1 complex autoactivation proceeds via a two-step mechanism requiring proteolytic activation of both C1r and C1s, reconstitution with MASP-2 alone is sufficient for complement activation by MBL. The results suggest that the catalytic activities of MASP-2 split between the two proteases of the C1 complex during the course of vertebrate complement evolution.
Collapse
Affiliation(s)
- T Vorup-Jensen
- Department of Medical Microbiology and Immunology, University of Aarhus, Aarhus, Denmark.
| | | | | | | | | | | | | | | | | | | |
Collapse
|
33
|
Abstract
In mammals, the classical B7 molecules expressed on antigen-presenting cells, B7-1 (CD80) and B7-2 (CD86), bind the structurally related glycoproteins CD28 and CTLA-4 (CD152), generating costimulatory signals that regulate the activation state of T cells. A recently identified human CD28-like protein, ICOS, also induces costimulatory signals in T cells when crosslinked with antibodies, but it is unclear whether ICOS is part of a B7-mediated regulatory pathway of previously unsuspected complexity, or whether it functions independently and in parallel. Here, we report that, rather than binding B7-1 or B7-2, ICOS binds a new B7-related molecule of previously unknown function that we call LICOS (for ligand of ICOS). At 37 degrees C, LICOS binds only to ICOS but, at lower, non-physiological temperatures, it also binds weakly to CD28 and CTLA-4. Sequence comparisons suggest that LICOS is the homologue of a molecule expressed by avian macrophages and of a murine protein whose expression is induced in non-lymphoid organs by tumour necrosis factor alpha (TNFalpha). Our results define the components of a distinct and novel costimulatory pathway and raise the possibility that LICOS, rather than B7-1 or B7-2, is the contemporary homologue of a primordial vertebrate costimulatory ligand.
Collapse
MESH Headings
- Amino Acid Sequence
- Animals
- Antigens, CD
- Antigens, Differentiation, T-Lymphocyte/genetics
- Antigens, Differentiation, T-Lymphocyte/metabolism
- Base Sequence
- Cell Line, Transformed
- DNA, Complementary
- Humans
- Inducible T-Cell Co-Stimulator Ligand
- Inducible T-Cell Co-Stimulator Protein
- Ligands
- Membrane Glycoproteins/genetics
- Membrane Glycoproteins/metabolism
- Mice
- Molecular Sequence Data
- Proteins/genetics
- Proteins/metabolism
- Receptors, Antigen, T-Cell/genetics
- Receptors, Antigen, T-Cell/metabolism
- Sequence Homology, Amino Acid
- Surface Plasmon Resonance/methods
Collapse
Affiliation(s)
- D Brodie
- Sir William Dunn School of Pathology, The University of Oxford, Oxford, OX1 3RE, UK
| | | | | | | | | | | | | | | |
Collapse
|
34
|
Abstract
Nest building was measured in "active" (housed with access to running wheels) and "sedentary" (without wheel access) mice (Mus domesticus) from four replicate lines selected for 10 generations for high voluntary wheel-running behavior, and from four randombred control lines. Based on previous studies of mice bidirectionally selected for thermoregulatory nest building, it was hypothesized that nest building would show a negative correlated response to selection on wheel-running. Such a response could constrain the evolution of high voluntary activity because nesting has also been shown to be positively genetically correlated with successful production of weaned pups. With wheel access, selected mice of both sexes built significantly smaller nests than did control mice. Without wheel access, selected females also built significantly smaller nests than did control females, but only when body mass was excluded from the statistical model, suggesting that body mass mediated this correlated response to selection. Total distance run and mean running speed on wheels was significantly higher in selected mice than in controls, but no differences in amount of time spent running were measured, indicating a complex cause of the response of nesting to selection for voluntary wheel running.
Collapse
Affiliation(s)
- P A Carter
- Department of Zoology, University of Wisconsin, Madison 53706-1381, USA.
| | | | | | | |
Collapse
|
35
|
Abstract
T cell antigen recognition is accompanied by cytoskeletal polarization towards the APC and large-scale redistribution of cell surface molecules into 'supramolecular activation clusters' (SMACs), forming an organized contact interface termed the 'immunological synapse' (IS). Molecules are arranged in the IS in a micrometer scale bull's eye pattern with a central accumulation of TCR/peptide-MHC (the cSMAC) surrounded by a peripheral ring of adhesion molecules (the pSMAC). We propose that segregation of cell surface molecules on a much smaller scale initiates TCR triggering, which drives the formation of the IS by active transport processes. IS formation may function as a checkpoint for full T cell activation, integrating information on the presence and quality of TCR ligands and the nature and activation state of the APC.
Collapse
|
36
|
Hunter AJ, Morency JR, Senior CL, Davis SJ, Fraser ME. Continuous emissions monitoring using spark-induced breakdown spectroscopy. J Air Waste Manag Assoc 2000; 50:111-117. [PMID: 10680371 DOI: 10.1080/10473289.2000.10463982] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
A new technology for monitoring airborne heavy metals on aerosols and particulates based on spark-induced breakdown spectroscopy (SIBS) was evaluated at a joint U.S. Environmental Protection Agency (EPA)/U.S. Department of Energy test at the rotary kiln incinerator simulator (RKIS) facility at EPA/Research Triangle Park, NC, in September 1997. The instrument was configured to measure lead and chromium in a simulated combustion flue gas in real time and in situ at target levels of 15 and 75 micrograms/dry standard cubic meters. Actual metal concentrations were measured during the tests using EPA Reference Method (RM) 29. The SIBS technology detected both lead and chromium at the low- and high-level concentrations. Additionally, the hardware performed without failure for more than 100 hr of operation and acquired data for 100% of the RM tests. The chromium data were well correlated with concentration increases resulting from duct operations and pressure fluctuations that are known to entrain dust.
Collapse
Affiliation(s)
- A J Hunter
- Physical Sciences Inc., Andover, Massachusetts, USA
| | | | | | | | | |
Collapse
|
37
|
Abstract
B7-1 (CD80) and B7-2 (CD86) are glycoproteins expressed on antigen-presenting cells. The binding of these molecules to the T cell homodimers CD28 and CTLA-4 (CD152) generates costimulatory and inhibitory signals in T cells, respectively. The crystal structure of the extracellular region of B7-1 (sB7-1), solved to 3 A resolution, consists of a novel combination of two Ig-like domains, one characteristic of adhesion molecules and the other previously seen only in antigen receptors. In the crystal lattice, sB7-1 unexpectedly forms parallel, 2-fold rotationally symmetric homodimers. Analytical ultracentrifugation reveals that sB7-1 also dimerizes in solution. The structural data suggest a mechanism whereby the avidity-enhanced binding of B7-1 and CTLA-4 homodimers, along with the relatively high affinity of these interactions, favors the formation of very stable inhibitory signaling complexes.
Collapse
Affiliation(s)
- S Ikemizu
- Division of Structural Biology, Wellcome Trust Centre for Human Genetics, The University of Oxford, United Kingdom
| | | | | | | | | | | | | | | |
Collapse
|
38
|
Abstract
Phytochromes are a family of photoreceptors used by green plants to entrain their development to the light environment. The distribution of these chromoproteins has been expanded beyond photoautotrophs with the discovery of phytochrome-like proteins in the nonphotosynthetic eubacteria Deinococcus radiodurans and Pseudomonas aeruginosa. Like plant phytochromes, the D. radiodurans receptor covalently binds linear tetrapyrroles autocatalytically to generate a photochromic holoprotein. However, the attachment site is distinct, using a histidine to potentially form a Schiff base linkage. Sequence homology and mutational analysis suggest that D. radiodurans bacteriophytochrome functions as a light-regulated histidine kinase, which helps protect the bacterium from visible light.
Collapse
Affiliation(s)
- S J Davis
- Laboratory of Genetics, Cellular and Molecular Biology Program and Department of Horticulture, University of Wisconsin-Madison, 1575 Linden Drive, Madison, WI 53706, USA
| | | | | |
Collapse
|
39
|
Haas TL, Stitelman D, Davis SJ, Apte SS, Madri JA. Egr-1 mediates extracellular matrix-driven transcription of membrane type 1 matrix metalloproteinase in endothelium. J Biol Chem 1999; 274:22679-85. [PMID: 10428849 DOI: 10.1074/jbc.274.32.22679] [Citation(s) in RCA: 135] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Matrix metalloproteinase activity is instrumental in processes of cellular invasion. The interstitial invasion of endothelial cells during angiogenesis is accompanied by up-regulation of several matrix metalloproteinases, including membrane type 1 matrix metalloproteinase (MT1-MMP). In this study, we show that endothelial cells stimulated to undergo angiogenesis by a three-dimensional extracellular matrix environment increase production of the transcription factor Egr-1. Increased binding of Egr-1 to the MT1-MMP promoter correlates with enhanced transcriptional activity, whereas mutations in the Egr-1 binding site abrogate the increased transcription of MT1-MMP in the stimulated cells. These data identify Egr-1-mediated transcription of MT1-MMP as a mechanism by which endothelial cells can initiate an invasive phenotype in response to an alteration in extracellular matrix environment, thus functionally associating MT1-MMP with a growing number of proteins known to be up-regulated by Egr-1 in response to tissue injury or mechanical stress.
Collapse
Affiliation(s)
- T L Haas
- Department of Pathology, Yale University Medical School, New Haven, Connecticut 06520, USA
| | | | | | | | | |
Collapse
|
40
|
Butters TD, Sparks LM, Harlos K, Ikemizu S, Stuart DI, Jones EY, Davis SJ. Effects of N-butyldeoxynojirimycin and the Lec3.2.8.1 mutant phenotype on N-glycan processing in Chinese hamster ovary cells: application to glycoprotein crystallization. Protein Sci 1999; 8:1696-701. [PMID: 10452614 PMCID: PMC2144425 DOI: 10.1110/ps.8.8.1696] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
Heterologous gene expression in either (1) the glycosylation-defective, mutant Chinese hamster ovary cell line, Lec3.2.8.1, or (2) the presence of the alpha-glucosidase inhibitor, N-butyldeoxynojirimycin facilitates the trimming of N-linked glycans of glycoproteins to single N-acetylglucosamine (GlcNAc) residues with endoglycosidase H (endo H). Both approaches are somewhat inefficient, however, with as little as 12% of the total protein being rendered fully endo H-sensitive under these conditions. It is shown here that the combined effects of these approaches on the restriction of oligosaccharide processing are essentially additive, thereby allowing the production of glycoproteins that are essentially completely endo H-sensitive. The preparation of a soluble chimeric form of CD58, the ligand of the human T-cell surface recognition molecule CD2, illustrates the usefulness of the combined approach when expression levels are low or the deglycosylated protein is unstable at low pH. The endo H-treated chimera produced crystals of space group P3(1)21 or P3(2)21, and unit cell dimensions a = b = 116.4 A, c = 51.4 A alpha = beta = 90 degrees , gamma = 120 degrees , that diffract to a maximum resolution of 1.8 A.
Collapse
Affiliation(s)
- T D Butters
- Glycobiology Institute, Department of Biochemistry, The University of Oxford, United Kingdom
| | | | | | | | | | | | | |
Collapse
|
41
|
Davis SJ, Kurepa J, Vierstra RD. The Arabidopsis thaliana HY1 locus, required for phytochrome-chromophore biosynthesis, encodes a protein related to heme oxygenases. Proc Natl Acad Sci U S A 1999; 96:6541-6. [PMID: 10339624 PMCID: PMC26918 DOI: 10.1073/pnas.96.11.6541] [Citation(s) in RCA: 195] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/1999] [Accepted: 03/22/1999] [Indexed: 12/21/2022] Open
Abstract
The hy1 mutants of Arabidopsis thaliana fail to make the phytochrome-chromophore phytochromobilin and therefore are deficient in a wide range of phytochrome-mediated responses. Because this defect can be rescued by feeding seedlings biliverdin IXalpha, it is likely that the mutations affect an enzyme that converts heme to this phytochromobilin intermediate. By a combination of positional cloning and candidate-gene isolation, we have identified the HY1 gene and found it to be related to cyanobacterial, algal, and animal heme oxygenases. Three independent alleles of hy1 contain DNA lesions within the HY1 coding region, and a genomic sequence spanning the HY1 locus complements the hy1-1 mutation. HY1 is a member of a gene family and is expressed in a variety of A. thaliana tissues. Based on its homology, we propose that HY1 encodes a higher-plant heme oxygenase, designated AtHO1, responsible for catalyzing the reaction that opens the tetrapyrrole ring of heme to generate biliverdin IXalpha.
Collapse
Affiliation(s)
- S J Davis
- Laboratory of Genetics and the Cellular and Molecular Biology Program, University of Wisconsin, 1575 Linden Drive, Madison, WI 53706, USA
| | | | | |
Collapse
|
42
|
Rudd PM, Wormald MR, Harvey DJ, Devasahayam M, McAlister MS, Brown MH, Davis SJ, Barclay AN, Dwek RA. Oligosaccharide analysis and molecular modeling of soluble forms of glycoproteins belonging to the Ly-6, scavenger receptor, and immunoglobulin superfamilies expressed in Chinese hamster ovary cells. Glycobiology 1999; 9:443-58. [PMID: 10207177 DOI: 10.1093/glycob/9.5.443] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Most cell surface molecules are glycoproteins consisting of linear arrays of globular domains containing stretches of amino acid sequence with similarities to regions in other proteins. These conserved regions form the basis for the classification of proteins into superfamilies. Recombinant soluble forms of six leukocyte antigens belonging to the Ly-6 (CD59), scavenger receptor (CD5), and immunoglobulin (CD2, CD48, CD4, and Thy-1) superfamilies were expressed in the same Chinese hamster ovary cell line, thus providing an opportunity to examine the extent to which N-linked oligosaccharide processing might vary in a superfamily-, domain-, or protein-dependent manner in a given cell. While we found no evidence for superfamily-specific modifications of the glycans, marked differences were seen in the types of oligosaccharides attached to individual proteins within a given superfamily. The relative importance of local protein surface properties versus the overall tertiary structure of the molecules in directing this protein-specific variation was examined in the context of molecular models. These were constructed using the 3D structures of the proteins, glycan data from this study, and an oligosaccharide structural database. The results indicated that both the overall organization of the domains and the local protein structure can have a large bearing on site-specific glycan modification of cells in stasis. This level of control ensures that the surface of a single cell will display a diverse repertoire of glycans and precludes the presentation of multiple copies of a single oligosaccharide on the cell surface. The glycans invariably shield large regions of the protein surfaces although, for the glycoproteins examined here, these did not hinder the known active sites of the molecules. The models also indicated that sugars are likely to play a role in the packing of the native cell surface glycoproteins and to limit nonspecific protein-protein interactions. In addition, glycans located close to the cell membrane are likely to affect crucially the orientation of the glycoproteins to which they are attached.
Collapse
MESH Headings
- Animals
- Antigens, CD/chemistry
- Antigens, Differentiation/chemistry
- Antigens, Differentiation/metabolism
- Antigens, Ly/chemistry
- CD2 Antigens/chemistry
- CD4 Antigens/chemistry
- CD48 Antigen
- CHO Cells
- Carbohydrate Conformation
- Carbohydrate Sequence
- Cricetinae
- Glycoproteins/chemistry
- Glycoproteins/metabolism
- Glycosylation
- Humans
- Membrane Proteins
- Models, Molecular
- Molecular Sequence Data
- Oligosaccharides/analysis
- Protein Conformation
- Protein Processing, Post-Translational
- Protein Structure, Secondary
- Rats
- Receptors, Immunologic/chemistry
- Receptors, Lipoprotein
- Receptors, Scavenger
- Recombinant Proteins/chemistry
- Recombinant Proteins/metabolism
- Scavenger Receptors, Class B
- Thy-1 Antigens/chemistry
Collapse
Affiliation(s)
- P M Rudd
- Glycobiology Institute, Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK
| | | | | | | | | | | | | | | | | |
Collapse
|
43
|
Ikemizu S, Sparks LM, van der Merwe PA, Harlos K, Stuart DI, Jones EY, Davis SJ. Crystal structure of the CD2-binding domain of CD58 (lymphocyte function-associated antigen 3) at 1.8-A resolution. Proc Natl Acad Sci U S A 1999; 96:4289-94. [PMID: 10200255 PMCID: PMC16325 DOI: 10.1073/pnas.96.8.4289] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The binding of the cell surface molecule CD58 (formerly lymphocyte function-associated antigen 3) to its ligand, CD2, significantly increases the sensitivity of antigen recognition by T cells. This was the first heterophilic cell adhesion interaction to be discovered and is now an important paradigm for analyzing the structural basis of cell-cell recognition. The crystal structure of a CD2-binding chimeric form of CD58, solved to 1.8-A resolution, reveals that the ligand binding domain of CD58 has the expected Ig superfamily V-set topology and shares several of the hitherto unique structural features of CD2, consistent with previous speculation that the genes encoding these molecules arose via duplication of a common precursor. Nevertheless, evidence for considerable divergence of CD2 and CD58 is also implicit in the structures. Mutations that disrupt CD2 binding map to the highly acidic surface of the AGFCC'C" beta-sheet of CD58, which, unexpectedly, lacks marked shape complementarity to the equivalent, rather more basic CD58-binding face of human CD2. The specificity of the very weak interactions of proteins mediating cell-cell recognition may often derive largely from electrostatic complementarity, with shape matching at the protein-protein interface being less exact than for interactions that combine specificity with high affinity, such as those involving antibodies.
Collapse
Affiliation(s)
- S Ikemizu
- Laboratory of Molecular Biophysics, the Rex Richards Building, South Parks Road, Oxford, OX1 3QU, United Kingdom
| | | | | | | | | | | | | |
Collapse
|
44
|
Abstract
PURPOSE To prospectively evaluate pulmonary magnetic (MR) angiography as a diagnostic examination for acute pulmonary embolism (PE). MATERIALS AND METHODS Thirty-six consecutive patients (19 women, 17 men; age range, 28-84 years) underwent pulmonary digital subtraction angiography (DSA) and pulmonary MR angiography. MR angiograms were obtained during suspended respiration and the pulmonary arterial phase of gadolinium-based contrast medium injection. A steady-state gradient-recalled-echo sequence with free induction decay sampling was used. DSA studies were interpreted for the presence of acute PE by two independent radiologists; an adjudicator made the final decision on discordant interpretations. RESULTS By using DSA, a total of 19 acute pulmonary emboli were depicted in 13 patients. Prospectively, 13 of these emboli were depicted by using MR angiography. MR angiography missed six emboli: Four required the DSA adjudicator to make the decision, and one was in a patient whose MR angiogram was acquired during breathing. Four of these six emboli were small subsegmental emboli, and two were segmental. CONCLUSION Performed without pulmonary arterial catheterization, iodinated contrast media, or ionizing radiation, pulmonary MR angiography had a high accuracy for depicting lobar and segmental emboli, but was unable to depict four of five subsegmental emboli.
Collapse
Affiliation(s)
- A Gupta
- Department of Radiology, Sir Charles Gairdner Hospital, Queen Elizabeth II Medical Centre, Nedlands, Western Australia
| | | | | | | | | | | | | | | | | |
Collapse
|
45
|
Wyer JR, Willcox BE, Gao GF, Gerth UC, Davis SJ, Bell JI, van der Merwe PA, Jakobsen BK. T cell receptor and coreceptor CD8 alphaalpha bind peptide-MHC independently and with distinct kinetics. Immunity 1999; 10:219-25. [PMID: 10072074 DOI: 10.1016/s1074-7613(00)80022-9] [Citation(s) in RCA: 165] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
The T cell surface glycoprotein CD8 enhances T cell antigen recognition by binding to MHC class I molecules. We show that human CD8 alphaalpha binds to the MHC class I molecule HLA-A2 with an extremely low affinity (Kd approximately 0.2 mM at 37 degrees C) and with kinetics that are between 2 and 3 orders of magnitude faster than reported for T cell receptor/peptide-MHC interactions. Furthermore, CD8 alphaalpha had no detectable effect on a T cell receptor (TCR) binding to the same peptide-MHC class I complex. These binding properties provide an explanation as to why the CD8/MHC class I interaction is unable to initiate cell-cell adhesion and how it can enhance TCR recognition without interfering with its specificity.
Collapse
Affiliation(s)
- J R Wyer
- Nuffield Department of Clinical Medicine, Institute of Molecular Medicine, John Radcliffe Hospital, Oxford, United Kingdom
| | | | | | | | | | | | | | | |
Collapse
|
46
|
Abstract
Rapid progress has recently been made in characterising the structures of leukocyte cell-surface molecules. Detailed analyses of the structure and interactions of CD2 were the first involving a molecule that has not been directly linked to antigen recognition in the manner of antigen receptors or co-receptors. It seems highly likely that the properties of ligand binding by CD2 are relevant to the general mechanisms of cell-cell recognition. As an example of biological recognition, the defining characteristic of cell-cell contact is that it involves the simultaneous interaction of hundreds, if not thousands, of molecules. Affinity and kinetic analyses of ligand binding by CD2 indicated that the protein interactions mediating cell-cell contact, whilst highly specific, are much weaker than initially anticipated, probably due to the requirement that such contacts be easily reversible. Simultaneously, in addressing the mechanism of this mode of recognition, structural and mutational studies focussed on the role of charged residues clustered in the ligand-binding face of CD2, yielding the concept that electrostatic complementarity, rather than surface-shape complementarity, is the dominant feature of specific, low-affinity protein recognition at the cell surface by CD2. The crystallographic analysis of the CD2-binding domain of CD58 strongly supports this concept.
Collapse
Affiliation(s)
- S J Davis
- Nuffield Department of Clinical Medicine, John Radcliffe Hospital, Oxford, UK.
| | | | | | | |
Collapse
|
47
|
Davis SJ, Davies EA, Tucknott MG, Jones EY, van der Merwe PA. The role of charged residues mediating low affinity protein-protein recognition at the cell surface by CD2. Proc Natl Acad Sci U S A 1998; 95:5490-4. [PMID: 9576909 PMCID: PMC20404 DOI: 10.1073/pnas.95.10.5490] [Citation(s) in RCA: 62] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Insights into the structural basis of protein-protein recognition have come principally from the analysis of proteins such as antibodies, hormone receptors, and proteases that bind their ligands with relatively high affinity (Ka approximately 10(9) M-1). In contrast, few studies have been done on the very low affinity interactions mediating cell adhesion and cell-cell recognition. As a site of protein-protein recognition, the ligand binding face of the T lymphocyte cell-cell recognition molecule, CD2, which binds its ligands 10(4)- to 10(5)-fold more weakly than do antibodies and proteases, is unusual in being both very flat and highly charged. An analysis of the effect of mutations and ionic strength on CD2 binding to its ligand, CD48, indicates that these charged residues contribute little, if any, binding energy to this interaction. However, the loss of these charged residues is shown to markedly reduce ligand-binding specificity. Thus, the charged residues increase the specificity of CD2 binding without increasing the affinity. This phenomenon is likely to result from a requirement for electrostatic complementarity between charged binding surfaces to compensate for the removal, upon binding, of water interacting with the charged residues. It is proposed that this mode of recognition is highly suited to biological interactions requiring a low affinity because it uncouples increases in specificity from increases in affinity.
Collapse
Affiliation(s)
- S J Davis
- Molecular Sciences Division, Nuffield Department of Clinical Medicine, John Radcliffe Hospital, Oxford, OX3 9DU, United Kingdom.
| | | | | | | | | |
Collapse
|
48
|
Rudd PM, Morgan BP, Wormald MR, Harvey DJ, van den Berg CW, Davis SJ, Ferguson MA, Dwek RA. The glycosylation of the complement regulatory protein, human erythrocyte CD59. Adv Exp Med Biol 1998; 435:153-62. [PMID: 9498074 DOI: 10.1007/978-1-4615-5383-0_15] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Affiliation(s)
- P M Rudd
- Department of Biochemistry, University of Oxford, UK
| | | | | | | | | | | | | | | |
Collapse
|
49
|
Abstract
Thirty patients with 31 shoulders underwent clinical and radiologic evaluation 5 to 6 years after arthroscopic acromioplasty. The mean age was 51 years. The acromioclavicular (AC) joint was assessed for tenderness on palpation and pain on horizontal adduction of the shoulder. All patients underwent a radiologic examination consisting of an anteroposterior view of the AC joint and bilateral stress views. No patient had superior translation or widening of more than 1 mm of the AC joint on stress views on the unoperated side. On the operated side 12 (38%) shoulders showed signs of instability consisting of a superior translation of the clavicle of 2 to 3 mm, distraction on weight bearing view, or both. No severely osteoarthritic AC joint (grade 3 or 4) was unstable. The degree of osteoarthritis did not differ for both shoulders, suggesting that arthroscopic acromioplasty does not accelerate osteoarthritic change in the AC joint but can induce instability. Nine patients had tenderness over the AC joint and instability on stress views. They had a significantly reduced University of California Los Angeles score of 25 +/- 5 compared with the other patients (29.5 +/- 7). We conclude that preservation of the inferior capsule during arthroscopic acromioplasty is important for the integrity of the AC joint in patients without severe osteoarthritic changes.
Collapse
Affiliation(s)
- M S Kuster
- Klinik fur Orthopadische Chirurgie, Kantonsspital, Baden, Switzerland
| | | | | |
Collapse
|
50
|
Abstract
Green fluorescent protein (GFP) from Aequorea victoria has rapidly become a standard reporter in many biological systems. However, the use of GFP in higher plants has been limited by aberrant splicing of the corresponding mRNA and by protein insolubility. It has been shown that GFP can be expressed in Arabidopsis thaliana after altering the codon usage in the region that is incorrectly spliced, but the fluorescence signal is weak, possibly due to aggregation of the encoded protein. Through site-directed mutagenesis, we have generated a more soluble version of the codon-modified GFP called soluble-modified GFP (smGFP). The excitation and emission spectra for this protein are nearly identical to wild-type GFP. When introduced into A. thaliana, greater fluorescence was observed compared to the codon-modified GFP, implying that smGFP is 'brighter' because more of it is present in a soluble and functional form. Using the smGFP template, two spectral variants were created, a soluble-modified red-shifted GFP (smRS-GFP) and a soluble-modified blue-fluorescent protein (smBFP). The increased fluorescence output of smGFP will further the use of this reporter in higher plants. In addition, the distinct spectral characters of smRS-GFP and smBFP should allow for dual monitoring of gene expression, protein localization, and detection of in vivo protein-protein interactions.
Collapse
Affiliation(s)
- S J Davis
- Department of Horticulture, University of Wisconsin-Madison 53706, USA
| | | |
Collapse
|