Fibroblast-expressed LRRC15 is a receptor for SARS-CoV-2 spike and controls antiviral and antifibrotic transcriptional programs.

Although ACE2 is the primary receptor for Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) infection, a systematic assessment of host factors that regulate binding to SARS-CoV-2 spike protein has not been described. Here, we use whole-genome CRISPR activation to identify host factors controlling cellular interactions with SARS-CoV-2. Our top hit was a TLR-related cell surface receptor called leucine-rich repeat-containing protein 15 (LRRC15). LRRC15 expression was sufficient to promote SARS-CoV-2 spike binding where they form a cell surface complex. LRRC15 mRNA is expressed in human collagen-producing lung myofibroblasts and LRRC15 protein is induced in severe Coronavirus Disease 2019 (COVID-19) infection where it can be found lining the airways. Mechanistically, LRRC15 does not itself support SARS-CoV-2 infection, but fibroblasts expressing LRRC15 can suppress both pseudotyped and authentic SARS-CoV-2 infection in trans. Moreover, LRRC15 expression in fibroblasts suppresses collagen production and promotes expression of IFIT, OAS, and MX-family antiviral factors. Overall, LRRC15 is a novel SARS-CoV-2 spike-binding receptor that can help control viral load and regulate antiviral and antifibrotic transcriptional programs in the context of COVID-19 infection.

Pressure pushes tRNALys3 into excited conformational states.

Conformational dynamics play essential roles in RNA function. However, detailed structural characterization of excited states of RNA remains challenging. Here, we apply high hydrostatic pressure (HP) to populate excited conformational states of tRNALys3, and structurally characterize them using a combination of HP 2D-NMR, HP-SAXS (HP-small-angle X-ray scattering), and computational modeling. HP-NMR revealed that pressure disrupts the interactions of the imino protons of the uridine and guanosine U-A and G-C base pairs of tRNALys3. HP-SAXS profiles showed a change in shape, but no change in overall extension of the transfer RNA (tRNA) at HP. Configurations extracted from computational ensemble modeling of HP-SAXS profiles were consistent with the NMR results, exhibiting significant disruptions to the acceptor stem, the anticodon stem, and the D-stem regions at HP. We propose that initiation of reverse transcription of HIV RNA could make use of one or more of these excited states.

mRNA display reveals a class of high-affinity bromodomain-binding motifs that are not found in the human proteome.

Bromodomains (BDs) regulate gene expression by recognizing protein motifs containing acetyllysine. Although originally characterized as histone-binding proteins, it has since become clear that these domains interact with other acetylated proteins, perhaps most prominently transcription factors. The likely transient nature and low stoichiometry of such modifications, however, has made it challenging to fully define the interactome of any given BD. To begin to address this knowledge gap in an unbiased manner, we carried out mRNA display screens against a BD-the N-terminal BD of BRD3-using peptide libraries that contained either one or two acetyllysine residues. We discovered peptides with very strong consensus sequences and with affinities that are significantly higher than typical BD-peptide interactions. X-ray crystal structures also revealed modes of binding that have not been seen with natural ligands. Intriguingly, however, our sequences are not found in the human proteome, perhaps suggesting that strong binders to BDs might have been selected against during evolution.

Structural characterization of the ANTAR antiterminator domain bound to RNA.

Regulated transcription termination provides an efficient and responsive means to control gene expression. In bacteria, rho-independent termination occurs through the formation of an intrinsic RNA terminator loop, which disrupts the RNA polymerase elongation complex, resulting in its dissociation from the DNA template. Bacteria have a number of pathways for overriding termination, one of which is the formation of mutually exclusive RNA motifs. ANTAR domains are a class of antiterminator that bind and stabilize dual hexaloop RNA motifs within the nascent RNA chain to prevent terminator loop formation. We have determined the structures of the dimeric ANTAR domain protein EutV, from Enterococcus faecialis, in the absence of and in complex with the dual hexaloop RNA target. The structures illustrate conformational changes that occur upon RNA binding and reveal that the molecular interactions between the ANTAR domains and RNA are restricted to a single hexaloop of the motif. An ANTAR domain dimer must contact each hexaloop of the dual hexaloop motif individually to prevent termination in eubacteria. Our findings thereby redefine the minimal ANTAR domain binding motif to a single hexaloop and revise the current model for ANTAR-mediated antitermination. These insights will inform and facilitate the discovery of novel ANTAR domain RNA targets.

Cyclic peptides can engage a single binding pocket through highly divergent modes.

Cyclic peptide library screening technologies show immense promise for identifying drug leads and chemical probes for challenging targets. However, the structural and functional diversity encoded within such libraries is largely undefined. We have systematically profiled the affinity, selectivity, and structural features of library-derived cyclic peptides selected to recognize three closely related targets: the acetyllysine-binding bromodomain proteins BRD2, -3, and -4. We report affinities as low as 100 pM and specificities of up to 106-fold. Crystal structures of 13 peptide-bromodomain complexes reveal remarkable diversity in both structure and binding mode, including both α-helical and ß-sheet structures as well as bivalent binding modes. The peptides can also exhibit a high degree of structural preorganization. Our data demonstrate the enormous potential within these libraries to provide diverse binding modes against a single target, which underpins their capacity to yield highly potent and selective ligands.

Echocardiographic changes and impact on clinical management in pregnant women with heart disease.

BACKGROUND: While guidelines recommend echocardiography for pregnant women with heart disease, there are limited data on its effect on clinical practice. In this study, we investigated pregnancy-associated echocardiographic changes and their impact on management. METHODS: This was a retrospective study of pregnant women with heart disease followed at an academic medical centre from 2016 to 2020. Data on maternal intrapartum and postpartum echocardiograms were collected and the impact on management analysed. RESULTS: 421 echocardiograms in 232 pregnancies were included in the study. The most common cardiac diagnosis was CHD (60.8% of pregnancies), followed by cardiomyopathy (9.9%). The frequency of baseline echocardiographic abnormalities varied by diagnosis, with abnormal right ventricular systolic pressure being the most common (15.0% of pregnancies in CHD and 23.1% of pregnancies with cardiomyopathy). 39.2% of the 189 follow-up echocardiograms had a significant change from the prior study, with the most common changes being declines in right ventricular function (4.2%) or left ventricular function (3.7%), and increases in right ventricular systolic pressure (5.3%) and aortic size (21.2%). 17.8% of echocardiograms resulted in a clinical management change, with the most common change being shorter interval follow-up. CONCLUSIONS: Echocardiographic changes in pregnant women with heart disease are common, in particular increases in aortic size. Echocardiography results in changes in management in a small but significant proportion of patients. Further studies are needed to determine how other factors, including patient access and resource allocation, factor into the use of echocardiography during pregnancy.

Evaluation and Management of Infertility for Patients Without Insurance Coverage.

Infertility is a common condition which causes substantial patient distress and prompts patients to seek care in outpatient gynecologic offices. The evaluation and treatment of infertility can be costly and insurance coverage for these services varies widely. Obstetrician-gynecologists and other women's health care professionals often struggle with the approach for patients without insurance coverage for infertility care. This article reviews the status of insurance coverage for infertility services, reviews options for both the evaluation and management of infertility for patients who do not have infertility insurance coverage, and provides resources for ongoing advocacy and support for these patients.

Hybrid governance and disaster management in Freetown, Sierra Leone, Monrovia, Liberia, and Dar es Salaam, Tanzania.

This paper introduces a hybrid governance-referring to situations where state and non-state actors collectively provide key services-perspective to disaster management. It contends that hybridity is often the norm rather than the exception in disaster management, particularly in developing countries where the state is frequently weak and may be unable or unwilling to supply essential services. In these instances, risks are addressed by state and non-state entities, ranging from citizens and non-governmental organisations to customary authorities. Given their important role in risk reduction, the disruption of hybrid processes by attempting to bring them within the remit of the state may create rather than diminish risk. To make this argument, the paper first outlines the key tenants of hybridity and their applicability to disasters before illustrating hybridity through three case studies of hybrid risk management in three cities in Africa: Freetown, Sierra Leone; Monrovia, Liberia; and Dar es Salaam, Tanzania.

BET-Family Bromodomains Can Recognize Diacetylated Sequences from Transcription Factors Using a Conserved Mechanism.

Almost all eukaryotic proteins receive diverse post-translational modifications (PTMs) that modulate protein activity. Many histone PTMs are well characterized, heavily influence gene regulation, and are often predictors of distinct transcriptional programs. Although our understanding of the histone PTM network has matured, much is yet to be understood about the roles of transcription factor (TF) PTMs, which might well represent a similarly complex and dynamic network of functional regulation. Members of the bromodomain and extra-terminal domain (BET) family of proteins recognize acetyllysine residues and relay the signals encoded by these modifications. Here, we have investigated the acetylation dependence of several functionally relevant BET-TF interactions in vitro using surface plasmon resonance, nuclear magnetic resonance, and X-ray crystallography. We show that motifs known to be acetylated in TFs E2F1 and MyoD1 can interact with all bromodomains of BRD2, BRD3, and BRD4. The interactions are dependent on diacetylation of the motifs and show a preference for the first BET bromodomain. Structural mapping of the interactions confirms a conserved mode of binding for the two TFs to the acetyllysine binding pocket of the BET bromodomains, mimicking that of other already established functionally important histone- and TF-BET interactions. We also examined a motif from the TF RelA that is known to be acetylated but were unable to observe any interaction, regardless of the acetylation state of the sequence. Our findings overall advance our understanding of BET-TF interactions and suggest a physical link between the important diacetylated motifs found in E2F1 and MyoD1 and the BET-family proteins.

Mechanism of powellite crystallite expansion within nano-phase separated amorphous matrices under Au-irradiation.

A fundamental approach was taken to understand the implications of increased nuclear waste loading in the search for new materials for long-term radioisotope encapsulation. This study focused on the formation and radiation tolerance of glass ceramics with selectively induced CaMoO4 as a form to trap the problematic fission product molybdenum. Several samples were synthesised with up to 10 mol% MoO3 within a soda lime borosilicate matrix, exhibiting phase separation on the nano scale according to thermal analysis, which detected two glass transition temperatures. It is predicted that these two phases are a result of spinodal decomposition with Si-O-Ca-O-Si and Si-O-Ca-O-B units, with the latter phase acting as a carrier for MoO3. The solubility limit of molybdenum within this matrix was 1 mol%, after which crystallisation of CaMoO4 occurred, with crystallite size (CS) increasing and cell parameters decreasing as a function of [MoO3]. These materials were then subjected to irradiation with 7 MeV Au3+ ions to replicate the nuclear interactions resulting from α-decay. A dose of 3 × 1014 ions per cm2 was achieved, resulting in 1 dpa of damage within a depth of ∼1.5 µm, according to TRIM calculations. Glasses and glass ceramics were then analysed using BSE imaging, XRD refinement, and Raman spectroscopy to monitor changes induced by accumulated damage. Irradiation was not observed to cause any significant changes to the residual amorphous network, nor did it cause amorphisation of CaMoO4 based on the relative changes to particle size and density. Furthermore, the substitution of Ca2+ to form water-soluble Na2/NaGd-MoO4 assemblages did not occur, indicating that CaMoO4 is resilient to chemical modification following ion interactions. Au-irradiation did however cause CaMoO4 lattice parameter expansion, concurrent to growth in CS. This is predicted to be a dual parameter mechanism of alteration based on thermal expansion from electronic coupling, and the accumulation of defects arising from atomic displacements.

A Novel Purification Procedure for Active Recombinant Human DPP4 and the Inability of DPP4 to Bind SARS-CoV-2.

Proteases catalyse irreversible posttranslational modifications that often alter a biological function of the substrate. The protease dipeptidyl peptidase 4 (DPP4) is a pharmacological target in type 2 diabetes therapy primarily because it inactivates glucagon-like protein-1. DPP4 also has roles in steatosis, insulin resistance, cancers and inflammatory and fibrotic diseases. In addition, DPP4 binds to the spike protein of the MERS virus, causing it to be the human cell surface receptor for that virus. DPP4 has been identified as a potential binding target of SARS-CoV-2 spike protein, so this question requires experimental investigation. Understanding protein structure and function requires reliable protocols for production and purification. We developed such strategies for baculovirus generated soluble recombinant human DPP4 (residues 29-766) produced in insect cells. Purification used differential ammonium sulphate precipitation, hydrophobic interaction chromatography, dye affinity chromatography in series with immobilised metal affinity chromatography, and ion-exchange chromatography. The binding affinities of DPP4 to the SARS-CoV-2 full-length spike protein and its receptor-binding domain (RBD) were measured using surface plasmon resonance and ELISA. This optimised DPP4 purification procedure yielded 1 to 1.8 mg of pure fully active soluble DPP4 protein per litre of insect cell culture with specific activity >30 U/mg, indicative of high purity. No specific binding between DPP4 and CoV-2 spike protein was detected by surface plasmon resonance or ELISA. In summary, a procedure for high purity high yield soluble human DPP4 was achieved and used to show that, unlike MERS, SARS-CoV-2 does not bind human DPP4.

Quality by design (QbD) approach to match tablet glossiness.

A quality by design (QbD) approach was used for a polyvinyl alcohol (PVA)-based coating to develop a 'look-alike' placebo tablet, which can match the glossiness (shine) of an innovator tablet. Critical coating parameters such as exhaust temperature, drying capacity, solid concentration in coating dispersion, and plasticizer concentration were studied using a full factorial design of experiment (DoE). Total of 20 experimental coating runs was executed on a pilot scale using a perforated pan coater. Coated tablets were evaluated visually against the innovator product by a panel of 13 volunteers using an individual questionnaire about the tablet appearance. The tablet appearance included factors such as tablet surface shine, surface roughness, and logo bridging. These data were analyzed using JMP software. Solid concentration in coating dispersion and drying capacity were found to be the key contributing parameters for tablet surface shine. Human observations were more discerning in spotting subtle differences in tablet appearance than Munsell evaluation. By the judicious selection of a solid concentration in coating dispersion and drying conditions, a look-alike placebo tablet was successfully developed. Change in tablet shape or size did not affect the tablet shine. However, replacement of PVA-based coating with hydroxypropyl methylcellulose (HPMC)-based coating resulted in reduced shine irrespective of tablet shape and size.

ß-Irradiation Effects on the Formation and Stability of CaMoO4 in a Soda Lime Borosilicate Glass Ceramic for Nuclear Waste Storage.

Molybdenum solubility is a limiting factor to actinide loading in nuclear waste glasses, as it initiates the formation of water-soluble crystalline phases such as alkali molybdates. To increase waste loading efficiency, alternative glass ceramic structures are sought that prove resistant to internal radiation resulting from radioisotope decay. In this study, selective formation of water-durable CaMoO4 in a soda lime borosilicate is achieved by introducing up to 10 mol % MoO3 in a 1:1 ratio to CaO using a sintering process. The resulting homogeneously dispersed spherical CaMoO4 nanocrystallites were analyzed using electron microscopy, X-ray diffraction (XRD), Raman and electron paramagnetic resonance (EPR) spectroscopies prior to and post irradiation, which replicated internal ß-irradiation damage on an accelerated scale. Following 0.77 to 1.34 GGy of 2.5 MeV electron radiation CaMoO4 does not exhibit amorphization or significant transformation. Nor does irradiation induce glass-in-glass phase separation in the surrounding amorphous matrix, or the precipitation of other molybdates, thus proving that excess molybdenum can be successfully incorporated into a structure that it is resistant to ß-irradiation proportional to 1000 years of storage without water-soluble byproducts. The CaMoO4 crystallites do however exhibit a nonlinear Scherrer crystallite size pattern with dose, as determined by a Rietveld refinement of XRD patterns and an alteration in crystal quality as deduced by anisotropic peak changes in both XRD and Raman spectroscopy. Radiation-induced modifications in the CaMoO4 tetragonal unit cell occurred primarily along the c-axis indicating relaxation of stacked calcium polyhedra. Concurrently, a strong reduction of Mo6+ to Mo5+ during irradiation is observed by EPR, which is believed to enhance Ca mobility. These combined results are used to hypothesize a crystallite size alteration model based on a combination of relaxation and diffusion-based processes initiated by added energy from ß-impingement and second-order structural modifications induced by defect accumulation.

The Incidence and Severity of Postoperative Pain following Inpatient Surgery.

OBJECTIVE: In recent years, there has been increased attention to pain management after surgery in the hospital setting along with financial enticement from the US government. The aim of this study is to evaluate the current efficacy of postoperative pain management. METHODS: In a prospective study, patients in an academic private nonprofit medical center were asked the same questions about their postoperative pain as in a previously published 2003 survey. Questionnaires on 1) pain intensity on a verbal categorical scale and 2) patient satisfaction with pain medication were completed in the patient's room before hospital discharge, and followed-up by telephone interviews at 1 and 2 weeks later. Numerical Pain Scale (NRS) pain scores were obtained at the same time points. Hospital Consumer Assessment of Healthcare Providers and Systems (HCAHPS) results for pain management were obtained at bedside interview along with standard mailed HCAHPS survey obtained by Press Ganey. RESULTS: Based on 441 surgical inpatients (Orthopedic, General, Neurosurgery, Gynecological) 12% of patients had "Severe-to-Extreme" pain and 54% had "Moderate-to-Extreme" pain at discharge. During the first 2 weeks after discharge, 13% of patients had "Severe-to-Extreme" pain and 46% had "Moderate-to-Extreme" pain. Pain scores at discharge and after discharge were negatively correlated with patient satisfaction with pain medication (P < 0.0001), indicating that increased pain intensity was associated with decreased patient satisfaction. For the HCAHPS question "how often was your pain well controlled?," 66% answered "Always" in the Press Ganey report versus 51% at bedside (P < 0.0001). CONCLUSIONS: The incidence of severe-to-extreme pain in patients before and after discharge following inpatient surgery is 12-13%, and this is a reduction from 10 years ago.

Two successful pregnancies -in patients taking Volanesorsen for familial chylomicronemia syndrome.

Familial chylomicronemia syndrome (FCS) is a rare inherited disorder characterized by severe hypertriglyceridemia, posing a heightened risk of acute pancreatitis. Recently, Volanesorsen, an APOC3 antisense oligonucleotide, gained approval for FCS treatment in the UK. Caution is advised during pregnancy due to limited safety data, although animal studies show no toxicity/teratogenicity. Two case scenarios are presented: In the first case, a patient with FCS continued Volanesorsen injections without having thrombocytopenia during an unplanned pregnancy until third trimester, maintaining triglyceride control. Upon discovering the pregnancy at 38 weeks, Volanesorsen was ceased, and a low-fat diet reinstated. Despite a heightened risk of pancreatitis, no episodes of pancreatitis occurred during the pregnancy. In the second case, stopping Volanesorsen before conception led to elevated triglycerides, and an episode of acute pancreatitis at 22 weeks, despite strict very low-fat diet and fibrate therapy from 14 weeks. At 23 weeks, Volanesorsen was reintroduced concurrently with regular therapeutic plasma exchange. No further episodes of pancreatitis occurred. In both case, fetal health was maintained throughout pregnancy, fetal scans revealed no anomalies, and planned C-sections delivered healthy babies without congenital issues. Both babies are well and developing normally at 24 and 19 months.

Discovery of High Affinity Cyclic Peptide Ligands for Human ACE2 with SARS-CoV-2 Entry Inhibitory Activity.

The development of effective antiviral compounds is essential for mitigating the effects of the COVID-19 pandemic. Entry of SARS-CoV-2 virions into host cells is mediated by the interaction between the viral spike (S) protein and membrane-bound angiotensin-converting enzyme 2 (ACE2) on the surface of epithelial cells. Inhibition of this viral protein-host protein interaction is an attractive avenue for the development of antiviral molecules with numerous spike-binding molecules generated to date. Herein, we describe an alternative approach to inhibit the spike-ACE2 interaction by targeting the spike-binding interface of human ACE2 via mRNA display. Two consecutive display selections were performed to direct cyclic peptide ligand binding toward the spike binding interface of ACE2. Through this process, potent cyclic peptide binders of human ACE2 (with affinities in the picomolar to nanomolar range) were identified, two of which neutralized SARS-CoV-2 entry. This work demonstrates the potential of targeting ACE2 for the generation of anti-SARS-CoV-2 therapeutics as well as broad spectrum antivirals for the treatment of SARS-like betacoronavirus infection.

Breaking it to them gently: fractured clavicle in the newborn.

Birth injuries are frequently seen in newborn infants. Clavicular fractures are the most commonly encountered bony injuries seen in clinical practice. The incidence of clavicle fracture ranges from 0.35 per cent to 2.9 per cent of births and remains undetected at the time of discharge from hospital in up to 40 per cent of cases. Clinical suspicion of fractured clavicle may be raised from history (shoulder dystocia) or clinical examination (spongy feeling or crepitus on palpation). This should be confirmed with imaging studies. Parents should have the diagnosis explained and be reassured that healing without residual deformity will occur without any medical intervention. Careful documentation of any confirmed clavicle fracture is important from medico-legal aspects. We present the case of a newborn clavicular fracture associated with shoulder dystocia, following a vaginal birth,.

Compared with conventional insemination, intracytoplasmic sperm injection provides no benefit in cases of nonmale factor infertility as evidenced by comparable euploidy rate.

OBJECTIVE: To evaluate whether differences in euploidy rates exist between intracytoplasmic sperm injection (ICSI) and conventional insemination (CI) in nonmale factor infertility cases. DESIGN: Retrospective cohort study. SETTING: A single, academically affiliated infertility center in the United States. PATIENTS: A total of 3554 patients who underwent in vitro fertilization cycles from January 2014 to December 2021. All cycles that had preimplantation testing for aneuploidy (PGT-A) performed by trophectoderm biopsy and had a postpreparation sperm concentration >4 million total motile sperm per milliliter were included. MAIN OUTCOME MEASURES: The primary outcome was the embryo euploidy rate per embryo biopsied in the ICSI vs. CI group. Secondary outcomes included the fertilization rate and number of embryos biopsied. Generalized estimating equations with a Poisson distribution were used to estimate the euploid rate ratio (with total embryos biopsied as an offset), while accounting for multiple retrievals per patient. To adjust for confounding, a propensity score model was fit for ICSI using 14 baseline female and male characteristics. RESULTS: Oocytes retrieved and the number of embryos biopsied were similar in both groups, while the fertilization rate per oocyte retrieved was significantly lower with ICSI (0.64 vs. 0.66). The proportion of euploid embryos in the ICSI group was significantly lower when compared with CI (0.47 vs. 0.52), with a euploid rate ratio of 0.89. Interestingly, when accounting for the variation in PGT reference laboratories over the study time period, adjusting for the date of procedure did not change the relationship between ICSI and euploid rate (rate ratio = 0.89); however, after adjusting for the PGT reference laboratory, the relationship between ICSI and euploid rate was no longer significant (rate ratio = 0.97). CONCLUSIONS: In the setting of nonmale factor infertility, ICSI resulted in a lower fertilization rate and an 11% lower embryo euploid rate compared with CI. Although the data are not statistically significant when adjusted for the PGT reference laboratory, we still can conclude that ICSI does not provide any benefit. These data support the recommendation that CI should be the preferred methodology for fertilization in nonmale factor infertility cases.

Factors Associated With Nonattendance at the Adult Congenital Heart Disease Clinic.

Adults with congenital heart disease (CHD) are a complex population for whom adult CHD-specific care results in better outcomes. Our objective was to identify factors associated with no-shows and cancelations in an adult CHD (ACHD) clinic and evaluate the efficacy of a social worker intervention to promote ambulatory follow-up. The medical record identified adults with a scheduled appointment in the adult CHD clinic from January 2017 to March 2021. Social worker intervention was performed between March 2020 and May 2021 and consisted of phone calls to those who did not show up. Logistic regression and descriptive statistics were performed. Of 8,431 scheduled visits, 56.7% were completed, 4.6% were no-shows, and 17.5% were canceled by patients. The factors associated with no-shows were Medicaid (odds ratio [OR] 1.63, 95% confidence interval [CI] 1.26 to 2.12, p <0.001), previous no-show (OR per 1% increase in previous no-show rate 1.13, 95% CI 1.12 to 1.15, p <0.001), satellite clinic location (OR 3.15, 95% CI 2.06 to 4.74, p <0.001), virtual visit (OR 1.97, 95% CI 1.28 to 2.92, p = 0.001), and Hispanic ethnicity (OR 1.48, 95% CI 1.03 to 2.10, p = 0.031). The factors associated with cancelations were female gender (OR 1.45, 95% CI 1.25 to 1.68, p <0.001) and virtual visits (OR 2.24, 95% CI 1.50 to 3.40, p <0.001). Social worker outreach calls did not impact frequency of rescheduling. No patients accepted additional support. In conclusion, Medicaid insurance, previous number of no-shows, and Hispanic ethnicity were found to be associated with a higher risk of no-show, identifying a high-risk population that may benefit from targeted interventions. Social worker outreach did not have an appreciable impact on the rescheduling rates.

Discovery and characterization of cyclic peptides selective for the C-terminal bromodomains of BET family proteins.

DNA-encoded cyclic peptide libraries can yield high-potency, high-specificity ligands against target proteins. We used such a library to seek ligands that could distinguish between paralogous bromodomains from the closely related bromodomain and extra-terminal domain family of epigenetic regulators. Several peptides isolated from a screen against the C-terminal bromodomain of BRD2, together with new peptides discovered in previous screens against the corresponding domain from BRD3 and BRD4, bound their targets with nanomolar and sub-nanomolar affinities. X-ray crystal structures of several of these bromodomain-peptide complexes reveal diverse structures and binding modes, which nevertheless display several conserved features. Some peptides demonstrate significant paralog-level specificity, although the physicochemical explanations for this specificity are often not clear. Our data demonstrate the power of cyclic peptides to discriminate between very similar proteins with high potency and hint that differences in conformational dynamics might modulate the affinity of these domains for particular ligands.