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1.
Contemp Clin Trials Commun ; 39: 101301, 2024 Jun.
Article in English | MEDLINE | ID: mdl-38711836

ABSTRACT

Cystic fibrosis (CF) is a multisystem, genetic disease with a significantly reduced life expectancy. Despite substantial progress in therapies in the last 10-15 years, there is still no cure. There are dozens of drugs in the development pipeline and multiple clinical trials are being conducted across the globe. The UK Cystic Fibrosis Trust's (CFT) Clinical Trials Accelerator Platform (CTAP) is a national initiative bringing together 25 UK based CF centres to support the CF community in accessing and participating in CF clinical trials. CTAP enables more CF centres to run a broader portfolio of trials and increases the range of CF studies available for UK patients. There are four large specialist CF centres based in London, all within a small geographical region as well as two smaller centres which deliver CF care. At the launch of CTAP, these centres formed a sub-network in a consortium-style collaboration. The purpose of the network was to ensure equity of access to trials for patients across the UK's capital, and to share experience and knowledge. Four years into the programme we have reviewed our practices through working group meetings and an online survey. We sought to identify strengths and areas for improvement. We share our findings here, as we believe they are relevant to others delivering research in regions outside of London and in other chronic diseases.

2.
Int J Gynecol Cancer ; 33(10): 1612-1620, 2023 10 02.
Article in English | MEDLINE | ID: mdl-37591611

ABSTRACT

OBJECTIVE: Although global disparities in survival rates for patients with ovarian cancer have been described, variation in care has not been assessed globally. This study aimed to evaluate global ovarian cancer care and barriers to care. METHODS: A survey was developed by international ovarian cancer specialists and was distributed through networks and organizational partners of the International Gynecologic Cancer Society, the Society of Gynecologic Oncology, and the European Society of Gynecological Oncology. Respondents received questions about care organization. Outcomes were stratified by World Bank Income category and analyzed using descriptive statistics and logistic regressions. RESULTS: A total of 1059 responses were received from 115 countries. Respondents were gynecological cancer surgeons (83%, n=887), obstetricians/gynecologists (8%, n=80), and other specialists (9%, n=92). Income category breakdown was as follows: high-income countries (46%), upper-middle-income countries (29%), and lower-middle/low-income countries (25%). Variation in care organization was observed across income categories. Respondents from lower-middle/low-income countries reported significantly less frequently that extensive resections were routinely performed during cytoreductive surgery. Furthermore, these countries had significantly fewer regional networks, cancer registries, quality registries, and patient advocacy groups. However, there is also scope for improvement in these components in upper-middle/high-income countries. The main barriers to optimal care for the entire group were patient co-morbidities, advanced presentation, and social factors (travel distance, support systems). High-income respondents stated that the main barriers were lack of surgical time/staff and patient preferences. Middle/low-income respondents additionally experienced treatment costs and lack of access to radiology/pathology/genetic services as main barriers. Lack of access to systemic agents was reported by one-third of lower-middle/low-income respondents. CONCLUSIONS: The current survey report highlights global disparities in the organization of ovarian cancer care. The main barriers to optimal care are experienced across all income categories, while additional barriers are specific to income levels. Taking action is crucial to improve global care and strive towards diminishing survival disparities and closing the care gap.


Subject(s)
Genital Neoplasms, Female , Gynecology , Ovarian Neoplasms , Surgeons , Humans , Female , Ovarian Neoplasms/surgery , Surveys and Questionnaires
3.
Thorax ; 78(8): 840-843, 2023 08.
Article in English | MEDLINE | ID: mdl-37286236

ABSTRACT

In 2018 we published the James Lind Alliance (JLA) top 10 priorities for clinical research in cystic fibrosis (CF), chosen jointly by the patient and clinical communities. These priorities have led to new research funding. To establish whether priorities have changed with novel modulator therapies, we undertook an online international update through a series of surveys and a workshop. Patients and clinicians (n=1417) chose the refreshed top 10 from 971 new research questions (suggested by patients and clinicians) and 15 questions from 2018. We are working with the international community to promote research based on these refreshed top 10 priorities.


Subject(s)
Biomedical Research , Cystic Fibrosis , Humans , Cystic Fibrosis/therapy , Health Priorities , Surveys and Questionnaires , Polyvinyl Alcohol , Povidone
4.
Sci Rep ; 13(1): 8954, 2023 06 02.
Article in English | MEDLINE | ID: mdl-37268661

ABSTRACT

The Y chromosome carries information about the demography of paternal lineages, and thus, can prove invaluable for retracing both the evolutionary trajectory of wild animals and the breeding history of domesticates. In horses, the Y chromosome shows a limited, but highly informative, sequence diversity, supporting the increasing breeding influence of Oriental lineages during the last 1500 years. Here, we augment the primary horse Y-phylogeny, which is currently mainly based on modern horse breeds of economic interest, with haplotypes (HT) segregating in remote horse populations around the world. We analyze target enriched sequencing data of 5 Mb of the Y chromosome from 76 domestic males, together with 89 whole genome sequenced domestic males and five Przewalski's horses from previous studies. The resulting phylogeny comprises 153 HTs defined by 2966 variants and offers unprecedented resolution into the history of horse paternal lineages. It reveals the presence of a remarkable number of previously unknown haplogroups in Mongolian horses and insular populations. Phylogenetic placement of HTs retrieved from 163 archaeological specimens further indicates that most of the present-day Y-chromosomal variation evolved after the domestication process that started around 4200 years ago in the Western Eurasian steppes. Our comprehensive phylogeny significantly reduces ascertainment bias and constitutes a robust evolutionary framework for analyzing horse population dynamics and diversity.


Subject(s)
Animals, Wild , Biological Evolution , Male , Animals , Horses/genetics , Phylogeny , Animals, Wild/genetics , Y Chromosome/genetics , Genome , Haplotypes , Genetic Variation , DNA, Mitochondrial/genetics
5.
Nat Commun ; 14(1): 693, 2023 02 08.
Article in English | MEDLINE | ID: mdl-36755044

ABSTRACT

We are currently witnessing transformative change for people with cystic fibrosis with the introduction of small molecule, mutation-specific drugs capable of restoring function of the defective protein, cystic fibrosis transmembrane conductance regulator (CFTR). However, despite being a single gene disorder, there are multiple cystic fibrosis-causing genetic variants; mutation-specific drugs are not suitable for all genetic variants and also do not correct all the multisystem clinical manifestations of the disease. For many, there will remain a need for improved treatments. Those patients with gene variants responsive to CFTR modulators may have found these therapies to be transformational; research is now focusing on safely reducing the burden of symptom-directed treatment. However, modulators are not available in all parts of the globe, an issue which is further widening existing health inequalities. For patients who are not suitable for- or do not have access to- modulator drugs, alternative approaches are progressing through the trials pipeline. There will be challenges encountered in design and implementation of these trials, for which the established global CF infrastructure is a major advantage. Here, the Cystic Fibrosis National Research Strategy Group of the UK NIHR Respiratory Translational Research Collaboration looks to the future of cystic fibrosis therapies and consider priorities for future research and development.


Subject(s)
Cystic Fibrosis , Humans , Cystic Fibrosis/drug therapy , Cystic Fibrosis/genetics , Cystic Fibrosis Transmembrane Conductance Regulator/genetics , Cystic Fibrosis Transmembrane Conductance Regulator/metabolism , Mutation , Genetic Therapy
6.
Commun Biol ; 5(1): 1320, 2022 12 13.
Article in English | MEDLINE | ID: mdl-36513809

ABSTRACT

Selection for system-wide morphological, physiological, and metabolic adaptations has led to extreme athletic phenotypes among geographically diverse horse breeds. Here, we identify genes contributing to exercise adaptation in racehorses by applying genomics approaches for racing performance, an end-point athletic phenotype. Using an integrative genomics strategy to first combine population genomics results with skeletal muscle exercise and training transcriptomic data, followed by whole-genome resequencing of Asian horses, we identify protein-coding variants in genes of interest in galloping racehorse breeds (Arabian, Mongolian and Thoroughbred). A core set of genes, G6PC2, HDAC9, KTN1, MYLK2, NTM, SLC16A1 and SYNDIG1, with central roles in muscle, metabolism, and neurobiology, are key drivers of the racing phenotype. Although racing potential is a multifactorial trait, the genomic architecture shaping the common athletic phenotype in horse populations bred for racing provides evidence for the influence of protein-coding variants in fundamental exercise-relevant genes. Variation in these genes may therefore be exploited for genetic improvement of horse populations towards specific types of racing.


Subject(s)
Genome-Wide Association Study , Genome , Horses/genetics , Animals , Phenotype , Genomics , Sequence Analysis, DNA
7.
Medicine (Baltimore) ; 97(49): e13238, 2018 Dec.
Article in English | MEDLINE | ID: mdl-30544383

ABSTRACT

Controversy exists regarding the best diagnostic and screening tool for sepsis outside the intensive care unit (ICU). Sequential organ failure assessment (SOFA) score has been shown to be superior to systemic inflammatory response syndrome (SIRS) criteria, however, the performance of "Red Flag sepsis criteria" has not been tested formally.The aim of the study was to investigate the ability of Red Flag sepsis criteria to identify the patients at high risk of sepsis-related death in comparison to SOFA based sepsis criteria. We also investigated the comparison of Red Flag sepsis to quick SOFA (qSOFA), SIRS, and national early warning score (NEWS) scores and factors influencing patient mortality.Patients were recruited into a 24-hour point-prevalence study on the general wards and emergency departments across all Welsh acute hospitals. Inclusion criteria were: clinical suspicion of infection and NEWS 3 or above in-line with established escalation criteria in Wales. Data on Red Flag sepsis and SOFA criteria was collected together with qSOFA and SIRS scores and 90-day mortality.459 patients were recruited over a 24-hour period. 246 were positive for Red Flag sepsis, mortality 33.7% (83/246); 241 for SOFA based sepsis criteria, mortality 39.4% (95/241); 54 for qSOFA, mortality 57.4% (31/54), and 268 for SIRS, mortality 33.6% (90/268). 55 patients were not picked up by any criteria. We found that older age was associated with death with OR (95% CI) of 1.03 (1.02-1.04); higher frailty score 1.24 (1.11-1.40); DNA-CPR order 1.74 (1.14-2.65); ceiling of care 1.55 (1.02-2.33); and SOFA score of 2 and above 1.69 (1.16-2.47).The different clinical tools captured different subsets of the at-risk population, with similar sensitivity. SOFA score 2 or above was independently associated with increased risk of death at 90 days. The sequalae of infection-related organ dysfunction cannot be reliably captured based on routine clinical and physiological parameters alone.


Subject(s)
Hospitalization , Organ Dysfunction Scores , Sepsis/diagnosis , Sepsis/mortality , Adolescent , Adult , Aged , Aged, 80 and over , Emergency Service, Hospital , Female , Humans , Male , Middle Aged , Prevalence , Risk Factors , Sepsis/therapy , Young Adult
8.
BMC Res Notes ; 11(1): 720, 2018 Oct 11.
Article in English | MEDLINE | ID: mdl-30309393

ABSTRACT

OBJECTIVE: Sepsis mortality is reported to be high worldwide, however recently the attributable fraction of mortality due to sepsis (AFsepsis) has been questioned. If improvements in treatment options are to be evaluated, it is important to know what proportion of deaths are potentially preventable or modifiable after a sepsis episode. The aim of the study was to establish the fraction of deaths directly related to the sepsis episode on the general wards and emergency departments. RESULTS: 839 patients were recruited over the two 24-h periods in 2016 and 2017. 521 patients fulfilled SEPSIS-3 criteria. 166 patients (32.4%) with sepsis and 56 patients (17.6%) without sepsis died within 90 days. Out of the 166 sepsis deaths 12 (7.2%) could have been directly related to sepsis, 28 (16.9%) possibly related and 96 (57.8%) were not related to sepsis. Overall AFsepsis was 24.1%. Upon analysis of the 40 deaths likely to be attributable to sepsis, we found that 31 patients (77.5%) had the Clinical Frailty Score ≥ 6, 28 (70%) had existing DNA-CPR order and 17 had limitations of care orders (42.5%).


Subject(s)
Cause of Death/trends , Emergency Service, Hospital/statistics & numerical data , Hospital Mortality/trends , Patients' Rooms/statistics & numerical data , Sepsis/mortality , Adolescent , Adult , Aged , Aged, 80 and over , Cross-Sectional Studies , Female , Hospitals/statistics & numerical data , Humans , Male , Middle Aged , Organ Dysfunction Scores , Prevalence , Risk Factors , Sepsis/epidemiology , Sepsis/pathology , United Kingdom/epidemiology
9.
Article in English | MEDLINE | ID: mdl-29547510

ABSTRACT

Although some countries have reduced asbestos consumption and instituted bans, other countries continue to produce and consume asbestos even as asbestos-related deaths mount and the associated societal costs are high. Asbestos production and consumption has declined globally; the number of bans has increased; and the speed at which countries have tapered off consumption has increased. Using country-level data, we study the economic impact of historical changes in the production and use of asbestos. We compare changes in gross domestic product (GDP) following the enactment of asbestos bans. We do not find any significant effect on GDP following an asbestos ban. In a regional case study, we compare changes in GDP and employment with changes in asbestos production. Regional-level data revealed a temporary employment decline at the local level that was then reversed.


Subject(s)
Asbestos , Environmental Exposure/prevention & control , Asbestos/economics , Asbestos/toxicity , Gross Domestic Product , Humans
10.
Int J Lang Commun Disord ; 53(4): 748-760, 2018 07.
Article in English | MEDLINE | ID: mdl-29500847

ABSTRACT

BACKGROUND: This study explores the psychometric properties of The Scenario Test UK, a culturally adapted version of the Dutch original (The Scenario Test) developed by van der Meulen et al. in 2010, which evaluates functional, daily-life communication in aphasia. The Scenario Test assesses communication in an interactive context with a supportive communication partner. AIMS: To evaluate the reliability (internal consistency, interrater and test-retest reliability) and construct validity (convergent, discriminant and known-groups validity) of The Scenario Test UK. METHODS & PROCEDURES: The Scenario Test UK and other language, cognition and praxis assessments were administered to persons with aphasia after stroke (3+ months post-stroke) and to non-aphasic controls. Participants were recruited primarily through community stroke groups. Measures were completed in an interview format. Standard psychometric criteria were used to evaluate reliability and construct validity. OUTCOMES & RESULTS: A total of 74 participants with aphasia and 20 participants without aphasia took part in The Scenario Test UK. The test showed high levels of reliability. Internal consistency (Cronbach's α = 0.92), interrater reliability (ICC = 0.95) and test-retest reliability (ICC = 0.96) were excellent. Interrater agreement in scores on the individual items ranged from good to excellent (κ = 0.41-1.00) for all but two items (item 4c κ = 0.38, item 6c κ = 0.36). The test demonstrated good levels of convergent (ρ = 0.37-0.75) and discriminant validity (ρ = -0.04 to 0.23). There was strong evidence for known groups validity (U = 132.50, p < .001), with those with aphasia scoring significantly lower [median (interquartile range-IQR) = 47 (39.8-51.0)] than those without aphasia [53 (52-54)]. CONCLUSIONS & IMPLICATIONS: The data support the reliability and validity of the Scenario Test UK as an assessment of functional, daily-life communication for persons with aphasia. Further testing is needed in independent samples on the measure's psychometric properties, including its sensitivity to change. Pending this testing, The test can be used as an assessment tool to evaluate communication skills with people with aphasia, to guide goal setting for therapy and to measure outcomes in response to therapy.


Subject(s)
Activities of Daily Living , Aphasia/diagnosis , Communication , Adult , Aged , Aged, 80 and over , Aphasia/psychology , Cross-Sectional Studies , Culture , Female , Humans , Interviews as Topic , Male , Middle Aged , Observer Variation , Psychometrics , Reproducibility of Results , United Kingdom , Young Adult
11.
Копенгаген; Всемирная организация здравоохранения. Европейское региональное бюро; 2017.
in Russian | WHO IRIS | ID: who-344115

ABSTRACT

В глобальном масштабе асбестовая индустрия сокращается, по мере того как страны вводят запрет на асбест и освобождаются от асбестовой зависимости. В настоящей публикации анализируются экономические последствия снижения производства и потребления асбеста, а также введения запрета на его применение. По данным на уровне стран, негативных экономических последствий не отмечается. Поскольку значение асбеста для экономики стран, производящих/потребляющих его в настоящее время, примерно такое же, как и там, где асбест запрещен, по результатам анализа можно предполагать, что внутренний валовой продукт этих стран также заметно не пострадает от запрета или сокращения потребления/производства асбеста. Кроме того, продолжение применения асбеста влечет за собой значительные затраты на медицинскую помощь, проведение очистных работ, покрытие судебных издержек и компенсационные выплаты.


Subject(s)
Asbestos , Environmental Exposure
12.
Copenhagen; World Health Organization. Regional Office for Europe; 2017.
in English | WHO IRIS | ID: who-344114

ABSTRACT

The global asbestos industry is shrinking as countries have increasingly banned and moved away from reliance on asbestos. This publication assesses the economic impact of declines in asbestos production and consumption and banning of asbestos use. According to country-level data, no negative economic impact is observed. Since the importance of asbestos to the economies of current producer/consumer countries is similar to that of other countries that have already banned its use, this analysis suggests that countries currently consuming/producing asbestos would not experience an observable effect on gross domestic product from a ban on or a decline in asbestos consumption/production. In addition, the continued use of asbestos carries substantial costs related to health, remediation and litigation.


Subject(s)
Asbestos , Environmental Exposure
13.
Chem Commun (Camb) ; 52(35): 5993-6, 2016 May 01.
Article in English | MEDLINE | ID: mdl-27063185

ABSTRACT

The reaction of the amido-stannate LiSn(NMe2)3 with the phosphine-borane (t)Bu2PHBH3 gives the Sn(II) hydride [(Me2NH)2Li{BH3P((t)Bu)2}2Sn(H)]; the first example of a hydridic stannate(ii) that is not supported by transition metal or ligand bonding.

14.
Chem Commun (Camb) ; 52(18): 3650-2, 2016 Mar 04.
Article in English | MEDLINE | ID: mdl-26853317

ABSTRACT

The presence of 18-crown-6 in the Lewis acid-promoted dehydrocoupling reaction of ammonia borane permits isolation of [(THF)BH2NH3](+) and [BH2(NH3)2](+) cations. [(THF)BH2NH3](+) reacts with Lewis bases to give either boron adducts or by deprotonation at nitrogen to give borazine and ammonia-borane.

15.
Dalton Trans ; 44(27): 12112-8, 2015 Jul 21.
Article in English | MEDLINE | ID: mdl-25790240

ABSTRACT

The aluminium amide Al(NMe2)3 acts as a stoichiometric or catalytic reagent in dehydrogenic Si-N bond formation using amines and silanes. Although of limited substrate scope, this represents the first p-block metal catalytic system for N-H/Si-H dehydrocoupling. The observed catalytic rate law for the formation of aminosilane products in a model study of one of the catalytic reactions suggests a mechanism involving the silane component in the deprotonation of the amine (possibly in the form of a hypervalent silicon hydride).

16.
Dalton Trans ; 44(9): 4141-7, 2015 Mar 07.
Article in English | MEDLINE | ID: mdl-25623046

ABSTRACT

Reaction of LiAlH4 with 1,2-phenylenediamine (1H4) in THF results in formation of the metallocyclic amido-/imido complex [{Al(1H2)}2{Al(1H)2}2][Li(THF)2]4 (3), while in the presence of various Lewis base ligands 1,8-diaminonaphthalene (2H4) gives the amido-('ate') complexes [Al(2H2)2](-)[Li(LL')](+) [L = THF, L' = PMDETA (N,N,N',N',N''-pentamethyldiethylenetriamine) (4); L = L' = TMEDA (N,N,N',N'-tetramethylethylenediamine) (5)]. The latter complexes provide evidence of intermediates in the proposed reaction pathway for formation of the cyclic framework of the tetraanion [{Al(1H2)}2{Al(1H)2}2](4-) of 3.

17.
Chem Commun (Camb) ; 50(23): 3007-9, 2014 Mar 21.
Article in English | MEDLINE | ID: mdl-24513788

ABSTRACT

The reaction of As(NMe2)3 with Mes*PHLi provides a direct source of the 1,3-diphosphaarsa-2-allyl anion, [(Mes*P)2As](-) (isoelectronic with the allyl anion). The equilibrium between the E,E and E,Z isomers of this anion depends on the extent of Li(+) ion-pairing.

18.
J Nucl Med ; 52(3): 424-30, 2011 Mar.
Article in English | MEDLINE | ID: mdl-21321268

ABSTRACT

UNLABELLED: Arginine-glycine-aspartate (RGD)-binding α(V)ß(3)-integrin and α(V)ß(5)-integrin play key roles in tumor angiogenesis. We examined an (18)F-labeled small peptide (fluciclatide [United States Adopted Name (ASAN)-approved, International Nonproprietary Name (INN)-proposed name], previously referred to as AH111585) containing an RGD sequence. Fluciclatide binds with a high (nM) affinity to α(V)ß(3)-integrin and α(V)ß(5)-integrin, which are highly expressed on tumors and the tumor neovasculature. In this study, (18)F-fluciclatide was used to examine the response of human glioblastoma xenografts to treatment with the antiangiogenic agent sunitinib. METHODS: U87-MG tumor uptake of (18)F-fluciclatide was determined by small-animal PET after longitudinal administration of the antiangiogenic agent sunitinib (a 2-wk dosing regimen). Tumor sizes were measured throughout the study, and tumor volumes were calculated. Tumor microvessel density (MVD) after therapy was also analyzed. RESULTS: Dynamic small-animal PET of (18)F-fluciclatide uptake after administration of the clinically relevant antiangiogenic agent sunitinib revealed a reduction in the tumor uptake of (18)F-fluciclatide compared with that in vehicle-treated controls over the 2-wk dosing regimen. Skeletal muscle, used as a reference tissue, showed equivalent (18)F-fluciclatide uptake in both therapy and control groups. A reduction in tumor MVD was also observed after treatment with the antiangiogenic agent. No significant changes in tumor volume were observed in the 2 groups. CONCLUSION: The data demonstrated that (18)F-fluciclatide detected changes in tumor uptake after acute antiangiogenic therapy markedly earlier than any significant volumetric changes were observable. These results suggest that this imaging agent may provide clinically important information for guiding patient care and monitoring the response to antiangiogenic therapy.


Subject(s)
Glioblastoma/drug therapy , Glioblastoma/metabolism , Indoles/therapeutic use , Integrin alphaVbeta3/metabolism , Peptides/pharmacokinetics , Polyethylene Glycols/pharmacokinetics , Pyrroles/therapeutic use , Receptors, Vitronectin/metabolism , Angiogenesis Inhibitors/therapeutic use , Animals , Cell Line, Tumor , Glioblastoma/diagnostic imaging , Humans , Male , Mice , Mice, Nude , Radionuclide Imaging , Radiopharmaceuticals/pharmacokinetics , Reproducibility of Results , Sensitivity and Specificity , Sunitinib
19.
J Phys Condens Matter ; 22(23): 235103, 2010 Jun 16.
Article in English | MEDLINE | ID: mdl-21393762

ABSTRACT

Fluorescence resonance energy transfer is a powerful technique which is often used to probe the properties of proteins and complex macromolecules. The technique relies on relatively large fluorescent dyes which are engineered into the molecule of interest. In the case of small proteins, these dyes may affect the stability of the protein, and modify the folding kinetics and the folding mechanisms which are being probed. Here we use atomistic simulation to investigate the effect that commonly used fluorescent dyes have on the folding of a four-helix bundle protein. We show that, depending on where the dyes are attached, their effect on the kinetic and thermodynamic properties of the protein may be significant. We find that, while the overall folding mechanism is not affected by the dyes, they can destabilize, or even stabilize, intermediate states.


Subject(s)
Biophysics/methods , Fluorescence Resonance Energy Transfer/methods , Fluorescent Dyes/pharmacology , Protein Folding , Proteins/chemistry , Computer Simulation , Fluorescent Dyes/chemistry , Kinetics , Models, Molecular , Models, Theoretical , Molecular Conformation , Peptides/chemistry , Thermodynamics
20.
J Chem Phys ; 131(6): 065101, 2009 Aug 14.
Article in English | MEDLINE | ID: mdl-19691411

ABSTRACT

Förster resonance energy transfer is an increasingly popular method for studying protein folding at single molecule resolution. By attaching dye molecules to particular residues in a protein molecule and measuring the energy transfer to the acceptor dye on excitation of the donor dye, information about the separation of the dyes can be obtained. Here we use an atomistic coarse-grained molecular model of the protein and dyes to look at the assumption that the dyes rotate freely during the donor decay time. We find that although complete orientational averaging does not always occur, the consequences of this are not extreme. Even in the native state, the errors in efficiency, which result from incorrectly assuming kappa2=2/3, are smaller than the typical experimental error of an efficiency measurement. The orientational freedom of the dyes originates both from the dynamics of the linker and dye molecules and also from the movements of the protein chain itself. In the unfolded state, the movements of the protein chain are sufficient to provide complete, or almost complete, orientational averaging within the donor lifetime. Increasing the rigidity of the dyes therefore has only a very small effect on the measured efficiencies in the unfolded state. In the native state the contribution of the linker and dye dynamics to orientational averaging is larger; nevertheless increasing the rigidity still has only a small effect on the measured efficiency.


Subject(s)
Coloring Agents/chemistry , Fluorescence Resonance Energy Transfer/methods , Proteins/chemistry , Models, Molecular
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