Pharmacological analysis and structure determination of 7-methylcyanopindolol–bound b1-adrenergic receptor

Comparisons between structures of the b1-adrenergic receptor (AR) bound to either agonists, partial agonists, or weak partial agonists led to the proposal that rotamer changes of Ser5.46, coupled to a contraction of the binding pocket, are sufficient to increase the probability of receptor activation. (RS)-4-[3 (tertbutylamino)-2-hydroxypropoxy]-1H-indole-2 carbonitrile (cyanopindolol) is a weak partial agonist of b1AR and, based on the hypothesis above, we predicted that the addition of a methyl group to form 4-[(2S)-3 (tert-butylamino)-2-hydroxypropoxy]-7-methyl-1H-indole-2 carbonitrile (7-methylcyanopindolol) would dramatically reduce its efficacy. An eight-step synthesis of 7- methylcyanopindolol was developed and its pharmacology was analyzed. 7-Methylcyanopindolol bound with similar affinity to cyanopindolol to both b1AR and b2AR. As predicted, the efficacy of 7-methylcyanopindolol was reduced significantly compared with cyanopindolol, acting as a very weak partial agonist of turkey b1AR and an inverse agonist of human b2AR. The structure of 7-methylcyanopindolol–bound b1AR was determined to 2.4-Å resolution and found to be virtually identical to the structure of cyanopindolol-bound b1AR. The major differences in the orthosteric binding pocket are that it has expanded by 0.3 Å in 7-methylcyanopindolol–bound b1AR and the hydroxyl group of Ser5.46 is positioned 0.8 Å further from the ligand, with respect to the position of the Ser5.46 side chain in cyanopindololbound b1AR. Thus, the molecular basis for the reduction in efficacy of 7 methylcyanopindolol compared with cyanopindolol may be regarded as the opposite of the mechanism proposed for the increase in efficacy of agonists compared with antagonists

Pi sampling: a methodical and flexible approach to initial macromolecular crystallization screening

Pi sampling, derived from the incomplete factorial approach, is an effort to maximize the diversity of macromolecular crystallization conditions and to facilitate the preparation of 96-condition initial screens

Insight into partial agonism by observing multiple equilibria for ligand-bound and Gs-mimetic nanobody-bound β1-adrenergic receptor.

A complex conformational energy landscape determines G-protein-coupled receptor (GPCR) signalling via intracellular binding partners (IBPs), e.g., Gs and β-arrestin. Using 13C methyl methionine NMR for the β1-adrenergic receptor, we identify ligand efficacy-dependent equilibria between an inactive and pre-active state and, in complex with Gs-mimetic nanobody, between more and less active ternary complexes. Formation of a basal activity complex through ligand-free nanobody-receptor interaction reveals structural differences on the cytoplasmic receptor side compared to the full agonist-bound nanobody-coupled form, suggesting that ligand-induced variations in G-protein interaction underpin partial agonism. Significant differences in receptor dynamics are observed ranging from rigid nanobody-coupled states to extensive μs-to-ms timescale dynamics when bound to a full agonist. We suggest that the mobility of the full agonist-bound form primes the GPCR to couple to IBPs. On formation of the ternary complex, ligand efficacy determines the quality of the interaction between the rigidified receptor and an IBP and consequently the signalling level

Towards an uncertain politics of professionalism: teacher and nurse identities in flux

This paper is about the nature of contemporary professional identity. It looks at the ways in which 'discursive dynamics' come to re-write the professional teacher and nurse as split, plural and conflictual selves, as they seek to come to terms with a political impetus written through what the authors term an 'economy of performance' in uncertain conflict with various 'ecologies of practice'. The teacher and nurse are thus located in a complicated nexus between policy, ideology and practice. Epistemologically, the paper offers a deconstruction of professional identities, and criticizes the reductive typologies and characterizations of current professionalism. Politically, it reaches towards a more nuanced account of professional identities, stressing the local, situated and indeterminable nature of professional practice, and the inescapable dimensions of trust, diversity and creativity

Complete Reversible Refolding of a G-Protein Coupled Receptor on a Solid Support

The factors defining the correct folding and stability of integral membrane proteins are poorly understood. Folding of only a few select membrane proteins has been scrutinised, leaving considerable deficiencies in knowledge for large protein families, such as G protein coupled receptors (GPCRs). Complete reversible folding, which is problematic for any membrane protein, has eluded this dominant receptor family. Moreover, attempts to recover receptors from denatured states are inefficient, yielding at best 40-70% functional protein. We present a method for the reversible unfolding of an archetypal family member, the β1-adrenergic receptor, and attain 100% recovery of the folded, functional state, in terms of ligand binding, compared to receptor which has not been subject to any unfolding and retains its original, folded structure. We exploit refolding on a solid support, which could avoid unwanted interactions and aggregation that occur in bulk solution. We determine the changes in structure and function upon unfolding and refolding. Additionally, we employ a method that is relatively new to membrane protein folding; pulse proteolysis. Complete refolding of β1-adrenergic receptor occurs in n-decyl-β-D-maltoside (DM) micelles from a urea-denatured state, as shown by regain of its original helical structure, ligand binding and protein fluorescence. The successful refolding strategy on a solid support offers a defined method for the controlled refolding and recovery of functional GPCRs and other membrane proteins that suffer from instability and irreversible denaturation once isolated from their native membranes

Disorders of sex development : insights from targeted gene sequencing of a large international patient cohort

Background: Disorders of sex development (DSD) are congenital conditions in which chromosomal, gonadal, or phenotypic sex is atypical. Clinical management of DSD is often difficult and currently only 13% of patients receive an accurate clinical genetic diagnosis. To address this we have developed a massively parallel sequencing targeted DSD gene panel which allows us to sequence all 64 known diagnostic DSD genes and candidate genes simultaneously. Results: We analyzed DNA from the largest reported international cohort of patients with DSD (278 patients with 46, XY DSD and 48 with 46, XX DSD). Our targeted gene panel compares favorably with other sequencing platforms. We found a total of 28 diagnostic genes that are implicated in DSD, highlighting the genetic spectrum of this disorder. Sequencing revealed 93 previously unreported DSD gene variants. Overall, we identified a likely genetic diagnosis in 43% of patients with 46, XY DSD. In patients with 46, XY disorders of androgen synthesis and action the genetic diagnosis rate reached 60%. Surprisingly, little difference in diagnostic rate was observed between singletons and trios. In many cases our findings are informative as to the likely cause of the DSD, which will facilitate clinical management. Conclusions: Our massively parallel sequencing targeted DSD gene panel represents an economical means of improving the genetic diagnostic capability for patients affected by DSD. Implementation of this panel in a large cohort of patients has expanded our understanding of the underlying genetic etiology of DSD. The inclusion of research candidate genes also provides an invaluable resource for future identification of novel genes

Evaluating the Effects of SARS-CoV-2 Spike Mutation D614G on Transmissibility and Pathogenicity.

Global dispersal and increasing frequency of the SARS-CoV-2 spike protein variant D614G are suggestive of a selective advantage but may also be due to a random founder effect. We investigate the hypothesis for positive selection of spike D614G in the United Kingdom using more than 25,000 whole genome SARS-CoV-2 sequences. Despite the availability of a large dataset, well represented by both spike 614 variants, not all approaches showed a conclusive signal of positive selection. Population genetic analysis indicates that 614G increases in frequency relative to 614D in a manner consistent with a selective advantage. We do not find any indication that patients infected with the spike 614G variant have higher COVID-19 mortality or clinical severity, but 614G is associated with higher viral load and younger age of patients. Significant differences in growth and size of 614G phylogenetic clusters indicate a need for continued study of this variant

Evaluating the Effects of SARS-CoV-2 Spike Mutation D614G on Transmissibility and Pathogenicity

Global dispersal and increasing frequency of the SARS-CoV-2 spike protein variant D614G are suggestive of a selective advantage but may also be due to a random founder effect. We investigate the hypothesis for positive selection of spike D614G in the United Kingdom using more than 25,000 whole genome SARS-CoV-2 sequences. Despite the availability of a large dataset, well represented by both spike 614 variants, not all approaches showed a conclusive signal of positive selection. Population genetic analysis indicates that 614G increases in frequency relative to 614D in a manner consistent with a selective advantage. We do not find any indication that patients infected with the spike 614G variant have higher COVID-19 mortality or clinical severity, but 614G is associated with higher viral load and younger age of patients. Significant differences in growth and size of 614G phylogenetic clusters indicate a need for continued study of this variant

Mirror, Mirror: Reflections on Developing the Emotionally Intelligent Practitioner

Nurturance, love, compassion, respect, humanity, self awareness, mind emptying and mindfulness are all qualities considered necessary for the development of the therapeutic relationship which is central to holistic care. Likewise raised levels of academia within nurse education have lead to the notion of emotional intelligence where such qualities, often associated with tacit and experiential knowledge, are inextricably bound with theory, practice and research. In an environment where nursing theory and research dominate, we suggest that such qualities are more likely to be attained if those expected to portray them, students, are themselves in receipt of the same or similar qualities from the organisations, namely education and practice. This paper explores the concept of preparedness in terms of developing the above qualities with those we educate and what might be required of educationalists in achieving this goal. Using psychoanalytic concepts of mirroring, holding and containing we explore the role of the educationalist in ‘preparing’ nurses to become emotionally intelligent practitioners. If we are to move from the rhetoric to the reality of an emotionally intelligent practitioner, nurse educators need to ensure that the student experience, in terms of their own learning, becomes the centre of their educational universe. We believe that this is more likely to occur when we as educationalists are able to personalise the educational process through mirroring love, care and nurturance, thus validating the emotional context of the students’ personal experience as a foundation for their learning

Creative approaches to health and social care education : knowing me, understanding you?

"Creative Approaches to Health and Social Care Education is an innovative new resource for lecturers teaching in this area. It inspires course delivery by exploring vibrant and engaging alternatives to traditional approaches, and challenging old techniques. The book is divided into three distinct sections: the first investigating the process of education; the second offering practical guidance for those implementing new ideas; and the third promoting support for lifelong learning."--back cover