Deubiquitylases (DUBs) are key regulators of the ubiquitin system which cleave ubiquitin moieties from proteins and polyubiquitin chains. Several DUBs have been implicated in various diseases and are ...attractive drug targets. We have developed a sensitive and fast assay to quantify in vitro DUB enzyme activity using matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry. Unlike other current assays, this method uses unmodified substrates, such as diubiquitin topoisomers. By analysing 42 human DUBs against all diubiquitin topoisomers we provide an extensive characterization of DUB activity and specificity. Our results confirm the high specificity of many members of the OTU and JAB/MPN/Mov34 metalloenzyme DUB families and highlight that all USPs tested display low linkage selectivity. We also demonstrate that this assay can be deployed to assess the potency and specificity of DUB inhibitors by profiling 11 compounds against a panel of 32 DUBs.
The recently identified plant photoreceptor UVR8 (UV RESISTANCE LOCUS 8) triggers regulatory changes in gene expression in response to ultraviolet-B (UV-B) light through an unknown mechanism. Here, ...cristallographie and solution structures of the UVR8 homodimer, together with mutagenesis and far-UV circular dichroism spectroscopy, reveal its mechanisms for UV-B perception and signal transduction. ß-propeller subunits form a remarkable, tryptophan-dominated, dimer interface stitched together by a complex salt-bridge network. Salt-bridging arginines flank the excitonically coupled cross-dimer tryptophan "pyramid" responsible for UV-B sensing. Photoreception reversibly disrupts salt bridges, triggering dimer dissociation and signal initiation. Mutation of a single tryptophan to phenylalanine retunes the photoreceptor to detect UV-C wavelengths. Our analyses establish how UVR8 functions as a photoreceptor without a prosthetic chromophore to promote plant development and survival in sunlight.
We report a new approach for creating chiral plasmonic nanomaterials. A previously unconsidered, far-field mechanism is utilized which enables chirality to be conveyed from a surrounding chiral ...molecular material to a plasmonic resonance of an achiral metallic nanostructure. Our observations break a currently held preconception that optical properties of plasmonic particles can most effectively be manipulated by molecular materials through near-field effects. We show that far-field electromagnetic coupling between a localized plasmon of a nonchiral nanostructure and a surrounding chiral molecular layer can induce plasmonic chirality much more effectively (by a factor of 103) than previously reported near-field phenomena. We gain insight into the mechanism by comparing our experimental results to a simple electromagnetic model which incorporates a plasmonic object coupled with a chiral molecular medium. Our work offers a new direction for the creation of hybrid molecular plasmonic nanomaterials that display significant chiroptical properties in the visible spectral region.
Escherichia coli possesses a number of specific K+ influx and efflux systems that maintain an appropriate intracellular K+ concentration. Although regulatory mechanisms have been identified for a ...number of these transport systems, the exact mechanism through which K+ concentration is sensed in the cell remains unknown. In this work we show that Kbp (K+ binding protein, formerly YgaU), a soluble 16-kDa cytoplasmic protein from Escherichia coli, is a highly specific K+ binding protein and is required for normal growth in the presence of high levels of external K+. Kbp binds a single potassium ion with high specificity over Na+ and other metal ions found in biological systems, although, in common with K+ transporters, it also binds Rb+ and Cs+. Dissection of the K+ binding determinants of Kbp suggests a mechanism through which Kbp is able to sense changes in K+ concentration over the relevant range of intracellular K+ concentrations.
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•E. coli Kbp is a highly specific cytoplasmic potassium binding protein•Kbp is required for normal growth of E. coli at high K+ concentrations•Both the BON and LysM domains of Kbp are required for full K+ binding•Structural analysis indicates global conformational changes on K+ binding
Ashraf et al. describe the discovery and structural analysis of a highly specific potassium binding protein, Kbp, from E. coli. Kbp is required for normal growth of E. coli at high K+ concentrations. Structural analysis shows that K+ binding induces a global conformation change in Kbp.
Underdamped terahertz-frequency delocalized phonon-like modes have long been suggested to play a role in the biological function of DNA. Such phonon modes involve the collective motion of many atoms ...and are prerequisite to understanding the molecular nature of macroscopic conformational changes and related biochemical phenomena. Initial predictions were based on simple theoretical models of DNA. However, such models do not take into account strong interactions with the surrounding water, which is likely to cause phonon modes to be heavily damped and localized. Here we apply state-of-the-art femtosecond optical Kerr effect spectroscopy, which is currently the only technique capable of taking low-frequency (GHz to THz) vibrational spectra in solution. We are able to demonstrate that phonon modes involving the hydrogen bond network between the strands exist in DNA at physiologically relevant conditions. In addition, the dynamics of the solvating water molecules is slowed down by about a factor of 20 compared with the bulk.
Hepatitis C in Black Individuals in the US: A Review Falade-Nwulia, Oluwaseun; Kelly, Sharon M; Amanor-Boadu, Sasraku ...
JAMA : the journal of the American Medical Association,
12/2023, Letnik:
330, Številka:
22
Journal Article
Recenzirano
IMPORTANCE: In the US, the prevalence of hepatitis C virus (HCV) is 1.8% among people who are Black and 0.8% among people who are not Black. Mortality rates due to HCV are 5.01/100 000 among people ...who are Black and 2.98/100 000 among people who are White. OBSERVATIONS: While people of all races and ethnicities experienced increased rates of incident HCV between 2015 and 2021, Black individuals experienced the largest percentage increase of 0.3 to 1.4/100 000 (367%) compared with 1.8 to 2.7/100 000 among American Indian/Alaska Native (50%), 0.3 to 0.9/100 000 among Hispanic (200%), and 0.9 to 1.6/100 000 among White (78%) populations. Among 47 687 persons diagnosed with HCV in 2019-2020, including 37 877 (79%) covered by Medicaid (7666 Black and 24 374 White individuals), 23.5% of Black people and 23.7% of White people with Medicaid insurance initiated HCV treatment. Strategies to increase HCV screening include electronic health record prompts for universal HCV screening, which increased screening tests from 2052/month to 4169/month in an outpatient setting. Awareness of HCV status can be increased through point-of-care testing in community-based settings, which was associated with increased likelihood of receiving HCV test results compared with referral for testing off-site (69% on-site vs 19% off-site, P < .001). Access to HCV care can be facilitated by patient navigation, in which an individual is assigned to work with a patient to help them access care and treatments; this was associated with greater likelihood of HCV care access (odds ratio, 3.7 95% CI, 2.9-4.8) and treatment initiation within 6 months (odds ratio, 3.2 95% CI, 2.3-4.2) in a public health system providing health care to individuals regardless of their insurance status or ability to pay compared with usual care. Eliminating Medicaid’s HCV treatment restrictions, including removal of a requirement for advanced fibrosis or a specialist prescriber, was associated with increased treatment rates from 2.4 persons per month to 72.3 persons per month in a retrospective study of 10 336 adults with HCV with no significant difference by race (526/1388 37.8% for Black vs 2706/8277 32.6% for White patients; adjusted odds ratio, 1.02 95% CI, 0.8-1.3). CONCLUSIONS AND RELEVANCE: In the US, the prevalence of HCV is higher in people who are Black than in people who are not Black. Point-of-care HCV tests, patient navigation, electronic health record prompts, and unrestricted access to HCV treatment in community-based settings have potential to increase diagnosis and treatment of HCV and improve outcomes in people who are Black.
Purpose of Review
The recent heroin and prescription opioid misuse epidemic has led to a sharp increase in the number of opioid overdose deaths in the USA. Notwithstanding the availability of three ...FDA-approved medications (methadone, buprenorphine, and naltrexone) to treat opioid use disorder, these medications are underutilized. This paper provides an update from the recent peer-reviewed literature on barriers to the use of these medications.
Findings
These barriers are interrelated and can be categorized as financial, regulatory, geographic, attitudinal, and logistic. While financial barriers are common to all three medications, other barriers are medication-specific.
Summary
The adverse impact of the current opioid epidemic on public health can be reduced by increasing access to effective pharmacotherapy for opioid use disorder.
How to study proteins by circular dichroism Kelly, Sharon M.; Jess, Thomas J.; Price, Nicholas C.
Biochimica et biophysica acta,
08/2005, Letnik:
1751, Številka:
2
Journal Article
Recenzirano
Circular dichroism (CD) is being increasingly recognised as a valuable technique for examining the structure of proteins in solution. However, the value of many studies using CD is compromised either ...by inappropriate experimental design or by lack of attention to key aspects of instrument calibration or sample characterisation. In this article, we summarise the basis of the CD approach and its application to the study of proteins, and then present clear guidelines on how reliable data can be obtained and analysed.
The (+) and (−) enantiomers of a new turn-inducing cyclopropyl dipeptide mimic have been synthesized and evaluated. The mimic derives its turn-inducing capabilities solely from the cyclopropyl group ...and without the conformational biasing that would be provided by side-chain substituents. The mimic and peptide-mimic hybrids prepared from it have been studied using a combination of spectroscopic techniques (NMR, IR, and CD). The dipeptide mimic itself displays intramolecular hydrogen bonding in organic solvents, which differs from that observed in natural peptide turns. In contrast, more elaborate peptide-mimic hybrids exhibit hydrogen bonding characteristics that vary with solvent but are consistent with structures found in the tetrapeptide portion (i → i + 3) of a native β-turn.
The National Institute on Alcohol Abuse and Alcoholism developed an alcohol screening instrument for youth based on epidemiologic data. This study examines the concurrent validity of this instrument, ...expanded to include tobacco and drugs, among pediatric patients, as well as the acceptability of its self-administration on an iPad.
Five hundred and twenty-five patients (54.5% female; 92.8% African American) aged 12 to 17 completed the Brief Screener for Tobacco, Alcohol, and other Drugs (BSTAD) via interviewer-administration or self-administration using an iPad. Diagnostic and Statistical Manual, Fifth Edition substance use disorders (SUDs) were identified using a modified Composite International Diagnostic Interview-2 Substance Abuse Module. Receiver operating characteristic curves, sensitivities, and specificities were obtained to determine optimal cut points on the BSTAD in relation to SUDs.
One hundred fifty-nine (30.3%) adolescents reported past-year use of ≥1 substances on the BSTAD: 113 (21.5%) used alcohol, 84 (16.0%) used marijuana, and 50 (9.5%) used tobacco. Optimal cut points for past-year frequency of use items on the BSTAD to identify SUDs were ≥6 days of tobacco use (sensitivity = 0.95; specificity = 0.97); ≥2 days of alcohol use (sensitivity = 0.96; specificity = 0.85); and ≥2 days of marijuana use (sensitivity = 0.80; specificity = 0.93). iPad self-administration was preferred over interviewer administration (z = 5.8; P < .001).
The BSTAD is a promising screening tool for identifying problematic tobacco, alcohol, and marijuana use in pediatric settings. Even low frequency of substance use among adolescents may indicate need for intervention.
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