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1.
Cell ; 186(18): 3921-3944.e25, 2023 08 31.
Artículo en Inglés | MEDLINE | ID: mdl-37582357

RESUMEN

Cancer driver events refer to key genetic aberrations that drive oncogenesis; however, their exact molecular mechanisms remain insufficiently understood. Here, our multi-omics pan-cancer analysis uncovers insights into the impacts of cancer drivers by identifying their significant cis-effects and distal trans-effects quantified at the RNA, protein, and phosphoprotein levels. Salient observations include the association of point mutations and copy-number alterations with the rewiring of protein interaction networks, and notably, most cancer genes converge toward similar molecular states denoted by sequence-based kinase activity profiles. A correlation between predicted neoantigen burden and measured T cell infiltration suggests potential vulnerabilities for immunotherapies. Patterns of cancer hallmarks vary by polygenic protein abundance ranging from uniform to heterogeneous. Overall, our work demonstrates the value of comprehensive proteogenomics in understanding the functional states of oncogenic drivers and their links to cancer development, surpassing the limitations of studying individual cancer types.


Asunto(s)
Neoplasias , Proteogenómica , Humanos , Neoplasias/genética , Oncogenes , Transformación Celular Neoplásica/genética , Variaciones en el Número de Copia de ADN
2.
Cell ; 184(19): 5031-5052.e26, 2021 09 16.
Artículo en Inglés | MEDLINE | ID: mdl-34534465

RESUMEN

Pancreatic ductal adenocarcinoma (PDAC) is a highly aggressive cancer with poor patient survival. Toward understanding the underlying molecular alterations that drive PDAC oncogenesis, we conducted comprehensive proteogenomic analysis of 140 pancreatic cancers, 67 normal adjacent tissues, and 9 normal pancreatic ductal tissues. Proteomic, phosphoproteomic, and glycoproteomic analyses were used to characterize proteins and their modifications. In addition, whole-genome sequencing, whole-exome sequencing, methylation, RNA sequencing (RNA-seq), and microRNA sequencing (miRNA-seq) were performed on the same tissues to facilitate an integrated proteogenomic analysis and determine the impact of genomic alterations on protein expression, signaling pathways, and post-translational modifications. To ensure robust downstream analyses, tumor neoplastic cellularity was assessed via multiple orthogonal strategies using molecular features and verified via pathological estimation of tumor cellularity based on histological review. This integrated proteogenomic characterization of PDAC will serve as a valuable resource for the community, paving the way for early detection and identification of novel therapeutic targets.


Asunto(s)
Adenocarcinoma/genética , Carcinoma Ductal Pancreático/genética , Neoplasias Pancreáticas/genética , Proteogenómica , Adenocarcinoma/diagnóstico , Adulto , Anciano , Anciano de 80 o más Años , Algoritmos , Carcinoma Ductal Pancreático/diagnóstico , Estudios de Cohortes , Células Endoteliales/metabolismo , Epigénesis Genética , Femenino , Dosificación de Gen , Genoma Humano , Glucólisis , Glicoproteínas/biosíntesis , Humanos , Masculino , Persona de Mediana Edad , Terapia Molecular Dirigida , Neoplasias Pancreáticas/diagnóstico , Fenotipo , Fosfoproteínas/metabolismo , Fosforilación , Pronóstico , Proteínas Quinasas/metabolismo , Proteoma/metabolismo , Especificidad por Sustrato , Transcriptoma/genética
3.
Cell ; 180(4): 729-748.e26, 2020 02 20.
Artículo en Inglés | MEDLINE | ID: mdl-32059776

RESUMEN

We undertook a comprehensive proteogenomic characterization of 95 prospectively collected endometrial carcinomas, comprising 83 endometrioid and 12 serous tumors. This analysis revealed possible new consequences of perturbations to the p53 and Wnt/ß-catenin pathways, identified a potential role for circRNAs in the epithelial-mesenchymal transition, and provided new information about proteomic markers of clinical and genomic tumor subgroups, including relationships to known druggable pathways. An extensive genome-wide acetylation survey yielded insights into regulatory mechanisms linking Wnt signaling and histone acetylation. We also characterized aspects of the tumor immune landscape, including immunogenic alterations, neoantigens, common cancer/testis antigens, and the immune microenvironment, all of which can inform immunotherapy decisions. Collectively, our multi-omic analyses provide a valuable resource for researchers and clinicians, identify new molecular associations of potential mechanistic significance in the development of endometrial cancers, and suggest novel approaches for identifying potential therapeutic targets.


Asunto(s)
Carcinoma/genética , Neoplasias Endometriales/genética , Regulación Neoplásica de la Expresión Génica , Proteoma/genética , Transcriptoma , Acetilación , Animales , Antígenos de Neoplasias/genética , Carcinoma/inmunología , Carcinoma/patología , Neoplasias Endometriales/inmunología , Neoplasias Endometriales/patología , Transición Epitelial-Mesenquimal/genética , Retroalimentación Fisiológica , Femenino , Inestabilidad Genómica , Humanos , Ratones , MicroARNs/genética , MicroARNs/metabolismo , Repeticiones de Microsatélite , Fosforilación , Procesamiento Proteico-Postraduccional , Proteoma/metabolismo , Transducción de Señal
4.
Cell ; 173(2): 371-385.e18, 2018 04 05.
Artículo en Inglés | MEDLINE | ID: mdl-29625053

RESUMEN

Identifying molecular cancer drivers is critical for precision oncology. Multiple advanced algorithms to identify drivers now exist, but systematic attempts to combine and optimize them on large datasets are few. We report a PanCancer and PanSoftware analysis spanning 9,423 tumor exomes (comprising all 33 of The Cancer Genome Atlas projects) and using 26 computational tools to catalog driver genes and mutations. We identify 299 driver genes with implications regarding their anatomical sites and cancer/cell types. Sequence- and structure-based analyses identified >3,400 putative missense driver mutations supported by multiple lines of evidence. Experimental validation confirmed 60%-85% of predicted mutations as likely drivers. We found that >300 MSI tumors are associated with high PD-1/PD-L1, and 57% of tumors analyzed harbor putative clinically actionable events. Our study represents the most comprehensive discovery of cancer genes and mutations to date and will serve as a blueprint for future biological and clinical endeavors.


Asunto(s)
Neoplasias/patología , Algoritmos , Antígeno B7-H1/genética , Biología Computacional , Bases de Datos Genéticas , Entropía , Humanos , Inestabilidad de Microsatélites , Mutación , Neoplasias/genética , Neoplasias/inmunología , Análisis de Componente Principal , Receptor de Muerte Celular Programada 1/genética
5.
Cell ; 173(2): 355-370.e14, 2018 04 05.
Artículo en Inglés | MEDLINE | ID: mdl-29625052

RESUMEN

We conducted the largest investigation of predisposition variants in cancer to date, discovering 853 pathogenic or likely pathogenic variants in 8% of 10,389 cases from 33 cancer types. Twenty-one genes showed single or cross-cancer associations, including novel associations of SDHA in melanoma and PALB2 in stomach adenocarcinoma. The 659 predisposition variants and 18 additional large deletions in tumor suppressors, including ATM, BRCA1, and NF1, showed low gene expression and frequent (43%) loss of heterozygosity or biallelic two-hit events. We also discovered 33 such variants in oncogenes, including missenses in MET, RET, and PTPN11 associated with high gene expression. We nominated 47 additional predisposition variants from prioritized VUSs supported by multiple evidences involving case-control frequency, loss of heterozygosity, expression effect, and co-localization with mutations and modified residues. Our integrative approach links rare predisposition variants to functional consequences, informing future guidelines of variant classification and germline genetic testing in cancer.


Asunto(s)
Células Germinativas/metabolismo , Neoplasias/patología , Variaciones en el Número de Copia de ADN , Bases de Datos Genéticas , Eliminación de Gen , Frecuencia de los Genes , Predisposición Genética a la Enfermedad , Genotipo , Células Germinativas/citología , Mutación de Línea Germinal , Humanos , Pérdida de Heterocigocidad/genética , Mutación Missense , Neoplasias/genética , Polimorfismo de Nucleótido Simple , Proteínas Proto-Oncogénicas c-met/genética , Proteínas Proto-Oncogénicas c-ret/genética , Proteínas Supresoras de Tumor/genética
7.
Epilepsia ; 65(6): e87-e96, 2024 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-38625055

RESUMEN

Febrile infection-related epilepsy syndrome (FIRES) is a subset of new onset refractory status epilepticus (NORSE) that involves a febrile infection prior to the onset of the refractory status epilepticus. It is unclear whether FIRES and non-FIRES NORSE are distinct conditions. Here, we compare 34 patients with FIRES to 30 patients with non-FIRES NORSE for demographics, clinical features, neuroimaging, and outcomes. Because patients with FIRES were younger than patients with non-FIRES NORSE (median = 28 vs. 48 years old, p = .048) and more likely cryptogenic (odds ratio = 6.89), we next ran a regression analysis using age or etiology as a covariate. Respiratory and gastrointestinal prodromes occurred more frequently in FIRES patients, but no difference was found for non-infection-related prodromes. Status epilepticus subtype, cerebrospinal fluid (CSF) and magnetic resonance imaging findings, and outcomes were similar. However, FIRES cases were more frequently cryptogenic; had higher CSF interleukin 6, CSF macrophage inflammatory protein-1 alpha (MIP-1a), and serum chemokine ligand 2 (CCL2) levels; and received more antiseizure medications and immunotherapy. After controlling for age or etiology, no differences were observed in presenting symptoms and signs or inflammatory biomarkers, suggesting that FIRES and non-FIRES NORSE are very similar conditions.


Asunto(s)
Fiebre , Estado Epiléptico , Humanos , Estado Epiléptico/etiología , Masculino , Femenino , Adulto , Persona de Mediana Edad , Fiebre/etiología , Fiebre/complicaciones , Adulto Joven , Adolescente , Epilepsia Refractaria/etiología , Niño , Convulsiones Febriles/etiología , Electroencefalografía , Anciano , Imagen por Resonancia Magnética , Síndromes Epilépticos , Preescolar
8.
Epilepsia ; 65(8): e148-e155, 2024 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-38837761

RESUMEN

In response to the evolving treatment landscape for new-onset refractory status epilepticus (NORSE) and the publication of consensus recommendations in 2022, we conducted a comparative analysis of NORSE management over time. Seventy-seven patients were enrolled by 32 centers, from July 2016 to August 2023, in the NORSE/FIRES biorepository at Yale. Immunotherapy was administered to 88% of patients after a median of 3 days, with 52% receiving second-line immunotherapy after a median of 12 days (anakinra 29%, rituximab 25%, and tocilizumab 19%). There was an increase in the use of second-line immunotherapies (odds ratio [OR] = 1.4, 95% CI = 1.1-1.8) and ketogenic diet (OR = 1.8, 95% CI = 1.3-2.6) over time. Specifically, patients from 2022 to 2023 more frequently received second-line immunotherapy (69% vs 40%; OR = 3.3; 95% CI = 1.3-8.9)-particularly anakinra (50% vs 13%; OR = 6.5; 95% CI = 2.3-21.0), and the ketogenic diet (OR = 6.8; 95% CI = 2.5-20.1)-than those before 2022. Among the 27 patients who received anakinra and/or tocilizumab, earlier administration after status epilepticus onset correlated with a shorter duration of status epilepticus (ρ = .519, p = .005). Our findings indicate an evolution in NORSE management, emphasizing the increasing use of second-line immunotherapies and the ketogenic diet. Future research will clarify the impact of these treatments and their timing on patient outcomes.


Asunto(s)
Dieta Cetogénica , Inmunoterapia , Estado Epiléptico , Humanos , Estado Epiléptico/terapia , Estado Epiléptico/tratamiento farmacológico , Masculino , Femenino , Dieta Cetogénica/métodos , Inmunoterapia/métodos , Inmunoterapia/tendencias , Adolescente , Adulto , Epilepsia Refractaria/terapia , Epilepsia Refractaria/dietoterapia , Niño , Anticuerpos Monoclonales Humanizados/uso terapéutico , Persona de Mediana Edad , Preescolar , Anticonvulsivantes/uso terapéutico , Adulto Joven , Rituximab/uso terapéutico , Manejo de la Enfermedad
9.
Brain Topogr ; 37(1): 116-125, 2024 01.
Artículo en Inglés | MEDLINE | ID: mdl-37966675

RESUMEN

Magnetoencephalography (MEG) is clinically used to localize interictal spikes in discrete brain areas of epilepsy patients through the equivalent current dipole (ECD) method, but does not account for the temporal dynamics of spike activity. Recent studies found that interictal spike propagation beyond the temporal lobe may be associated with worse postsurgical outcomes, but studies using whole-brain data such as in MEG remain limited. In this pilot study, we developed a tool that visualizes the spatiotemporal dynamics of interictal MEG spikes normalized to spike-free sleep activity to assess their onset and propagation patterns in patients with temporal lobe epilepsy (TLE). We extracted interictal source data containing focal epileptiform activity in awake and asleep states from seven patients whose MEG ECD clusters localized to the temporal lobe and normalized the data against spike-free sleep recordings. We calculated the normalized activity over time per cortical label, confirmed maximal activity at onset, and mapped the activity over a 10 ms interval onto each patient's brain using a custom-built Multi-Modal Visualization Tool. The onset of activity in all patients appeared near the clinically determined epileptogenic zone. By 10 ms, four of the patients had propagated source activity restricted to within the temporal lobe, and three had propagated source activity spread to extratemporal regions. Using this tool, we show that noninvasively identifying the onset and propagation of interictal spike activity in MEG can be achieved, which may help provide further insight into epileptic networks and guide surgical planning and interventions in patients with TLE.


Asunto(s)
Epilepsia del Lóbulo Temporal , Epilepsia , Humanos , Magnetoencefalografía/métodos , Epilepsia del Lóbulo Temporal/diagnóstico por imagen , Epilepsia del Lóbulo Temporal/cirugía , Proyectos Piloto , Electroencefalografía/métodos , Encéfalo , Epilepsia/cirugía
10.
Epilepsy Behav ; 158: 109928, 2024 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-38959747

RESUMEN

Temporal encephaloceles (TE) are an under-identified, potentially intervenable cause of epilepsy. This systematic review consolidates the current data to identify the major clinical, neuroimaging, and EEG features and surgical outcomes of epilepsy associated with TE. Literature searches were carried out using MEDLINE, Embase, PsycINFO, Scopus, and Cochrane Library databases from inception to December 7, 2023. Studies were included if they described clinical, neuroimaging, EEG, or surgical data in ≥5 patients with TE and epilepsy. Of 562 studies identified in the search, 24 met the eligibility criteria, reporting 423 unique patients with both epilepsy and TE. Compared to epilepsy patients without TE, those with TE had a higher mean age of seizure onset and were less likely to have a history of febrile seizures. Seizure semiologies were variable, but primarily mirrored temporal lobe onset patterns. Epilepsy patients with TE had a higher likelihood of having clinical or radiographic features of idiopathic intracranial hypertension (IIH) than those without. Brain MRI may show ipsilateral mesial temporal sclerosis (16 %). CT scans of the skull base usually revealed bony defects near the TE (90 %). Brain PET scans primarily showed ipsilateral temporal lobe hypometabolism (80 %), mostly in the anterior temporal lobe (67 %). Scalp EEG mostly lateralized ipsilateral to the implicated TE (92 % seizure onset) and localized to the temporal lobe (96 %). Intracranial EEG revealed seizure onset near the TE (11 of 12 cases including TE-adjacent electrodes) with variable timing of spread to the ipsilateral hippocampus. After surgical treatment of the TE, the rate of Engel I or ILAE 1 outcomes at one year was 75 % for lesionectomy, 85 % for anterior temporal lobectomy (ATL), and 80 % for ATL with amygdalohippocampectomy. Further studies are needed to better elucidate the relationship between IIH, TE, and epilepsy, improve the identification of TE, and optimize surgical interventions.


Asunto(s)
Encefalocele , Epilepsia , Humanos , Electroencefalografía , Encefalocele/cirugía , Encefalocele/complicaciones , Epilepsia/diagnóstico , Epilepsia/etiología , Epilepsia/cirugía , Lóbulo Temporal/cirugía , Lóbulo Temporal/diagnóstico por imagen , Resultado del Tratamiento
11.
Brief Bioinform ; 22(5)2021 09 02.
Artículo en Inglés | MEDLINE | ID: mdl-33461213

RESUMEN

MOTIVATION: Microsatellite instability (MSI) is a promising biomarker for cancer prognosis and chemosensitivity. Techniques are rapidly evolving for the detection of MSI from tumor-normal paired or tumor-only sequencing data. However, tumor tissues are often insufficient, unavailable, or otherwise difficult to procure. Increasing clinical evidence indicates the enormous potential of plasma circulating cell-free DNA (cfNDA) technology as a noninvasive MSI detection approach. RESULTS: We developed MSIsensor-ct, a bioinformatics tool based on a machine learning protocol, dedicated to detecting MSI status using cfDNA sequencing data with a potential stable MSIscore threshold of 20%. Evaluation of MSIsensor-ct on independent testing datasets with various levels of circulating tumor DNA (ctDNA) and sequencing depth showed 100% accuracy within the limit of detection (LOD) of 0.05% ctDNA content. MSIsensor-ct requires only BAM files as input, rendering it user-friendly and readily integrated into next generation sequencing (NGS) analysis pipelines. AVAILABILITY: MSIsensor-ct is freely available at https://github.com/niu-lab/MSIsensor-ct. SUPPLEMENTARY INFORMATION: Supplementary data are available at Briefings in Bioinformatics online.


Asunto(s)
ADN Tumoral Circulante/genética , Aprendizaje Automático , Inestabilidad de Microsatélites , Neoplasias/genética , Programas Informáticos , ADN Tumoral Circulante/sangre , Biología Computacional/métodos , Secuenciación de Nucleótidos de Alto Rendimiento/estadística & datos numéricos , Humanos , Límite de Detección , Repeticiones de Microsatélite , Neoplasias/sangre , Neoplasias/diagnóstico , Neoplasias/patología , Análisis de Secuencia de ADN
12.
Inorg Chem ; 62(23): 8789-8793, 2023 Jun 12.
Artículo en Inglés | MEDLINE | ID: mdl-37227222

RESUMEN

Here, we investigate the stereoelectronic requirements of a family of Fe/Co6Se8 molecular clusters to achieve a Goldilocks regime of substrate affinity for the catalytic coupling of tosyl azide and tert-butyl isocyanide. The reactivity of a catalytically competent iron-nitrenoid intermediate, observed in situ, is explored toward nitrene transfer and hydrogen-atom abstraction. The dual role of isocyanide, which, on the one hand, prevents catalyst degradation but, in large amounts, slows down reactivity, is exposed. The impact of distal changes (the number of neighboring active sites and the identity of supporting ligands) on the substrate affinity, electronic properties, and catalytic activity is investigated. Overall, the study reveals that the dynamic, push-pull interactions between the substrate (tBuNC), active site (Fe), and support (Co6Se8) create a regime where increased substrate activation occurs with facile dissociation.

13.
Clin Proteomics ; 19(1): 36, 2022 Oct 20.
Artículo en Inglés | MEDLINE | ID: mdl-36266629

RESUMEN

BACKGROUND: The identification of differentially expressed tumor-associated proteins and genomic alterations driving neoplasia is critical in the development of clinical assays to detect cancers and forms the foundation for understanding cancer biology. One of the challenges in the analysis of pancreatic ductal adenocarcinoma (PDAC) is the low neoplastic cellularity and heterogeneous composition of bulk tumors. To enrich neoplastic cells from bulk tumor tissue, coring, and laser microdissection (LMD) sampling techniques have been employed. In this study, we assessed the protein and KRAS mutation changes associated with samples obtained by these enrichment techniques and evaluated the fraction of neoplastic cells in PDAC for proteomic and genomic analyses. METHODS: Three fresh frozen PDAC tumors and their tumor-matched normal adjacent tissues (NATs) were obtained from three sampling techniques using bulk, coring, and LMD; and analyzed by TMT-based quantitative proteomics. The protein profiles and characterizations of differentially expressed proteins in three sampling groups were determined. These three PDACs and samples of five additional PDACs obtained by the same three sampling techniques were also subjected to genomic analysis to characterize KRAS mutations. RESULTS: The neoplastic cellularity of eight PDACs ranged from less than 10% to over 80% based on morphological review. Distinctive proteomic patterns and abundances of certain tumor-associated proteins were revealed when comparing the tumors and NATs by different sampling techniques. Coring and bulk tissues had comparable proteome profiles, while LMD samples had the most distinct proteome composition compared to bulk tissues. Further genomic analysis of bulk, cored, or LMD samples demonstrated that KRAS mutations were significantly enriched in LMD samples while coring was less effective in enriching for KRAS mutations when bulk tissues contained a relatively low neoplastic cellularity. CONCLUSIONS: In addition to bulk tissues, samples from LMD and coring techniques can be used for proteogenomic studies. The greatest enrichment of neoplastic cellularity is obtained with the LMD technique.

14.
Epilepsy Behav ; 131(Pt A): 108693, 2022 06.
Artículo en Inglés | MEDLINE | ID: mdl-35483204

RESUMEN

New-onset movement disorders have been frequently reported in association with the use of antiseizure medications (ASMs). The frequency of specific motor manifestations and the spectrum of their semiology for various ASMs have not been well characterized. We carried out a systematic review of literature and conducted a search on CINAHL, Cochrane Library, EMBASE, MEDLINE, PsycINFO, and Scopus from inception to April 2021. We compiled the data for all currently available ASMs using the conventional terminology of movement disorders. Among 5123 manuscripts identified by the search, 437 met the inclusion criteria. The largest number of reports of abnormal movements were in association with phenobarbital, valproic acid, lacosamide, and perampanel, and predominantly included tremor and ataxia. The majority of attempted interventions for all agents were discontinuation of the offending drug or dose reduction which led to the resolution of symptoms in most patients. Familiarity with the movement disorder phenomenology previously encountered in relation with specific ASMs facilitates early recognition of adverse effects and timely institution of targeted interventions.


Asunto(s)
Anticonvulsivantes , Trastornos del Movimiento , Anticonvulsivantes/efectos adversos , Humanos , Lacosamida , Trastornos del Movimiento/tratamiento farmacológico , Trastornos del Movimiento/etiología , Fenobarbital , Ácido Valproico
15.
Sensors (Basel) ; 21(10)2021 May 11.
Artículo en Inglés | MEDLINE | ID: mdl-34064694

RESUMEN

Sleep disturbances are common in Alzheimer's disease and other neurodegenerative disorders, and together represent a potential therapeutic target for disease modification. A major barrier for studying sleep in patients with dementia is the requirement for overnight polysomnography (PSG) to achieve formal sleep staging. This is not only costly, but also spending a night in a hospital setting is not always advisable in this patient group. As an alternative to PSG, portable electroencephalography (EEG) headbands (HB) have been developed, which reduce cost, increase patient comfort, and allow sleep recordings in a person's home environment. However, naïve applications of current automated sleep staging systems tend to perform inadequately with HB data, due to their relatively lower quality. Here we present a deep learning (DL) model for automated sleep staging of HB EEG data to overcome these critical limitations. The solution includes a simple band-pass filtering, a data augmentation step, and a model using convolutional (CNN) and long short-term memory (LSTM) layers. With this model, we have achieved 74% (±10%) validation accuracy on low-quality two-channel EEG headband data and 77% (±10%) on gold-standard PSG. Our results suggest that DL approaches achieve robust sleep staging of both portable and in-hospital EEG recordings, and may allow for more widespread use of ambulatory sleep assessments across clinical conditions, including neurodegenerative disorders.


Asunto(s)
Aprendizaje Profundo , Electroencefalografía , Humanos , Polisomnografía , Sueño , Fases del Sueño
16.
J Biol Chem ; 292(52): 21578-21589, 2017 12 29.
Artículo en Inglés | MEDLINE | ID: mdl-29118188

RESUMEN

RhoGC is a fusion protein from the aquatic fungus Blastocladiella emersonii, combining a type I rhodopsin domain with a guanylyl cyclase domain. It has generated excitement as an optogenetics tool for the manipulation of cyclic nucleotide signaling pathways. To investigate the regulation of the cyclase activity, we isolated the guanylyl cyclase domain from Escherichia coli with (GCwCCRho) and without (GCRho) the coiled-coil linker. Both constructs were constitutively active but were monomeric as determined by size-exclusion chromatography and analytical ultracentrifugation, whereas other class III nucleotidyl cyclases are functional dimers. We also observed that crystals of GCRho have only a monomer in an asymmetric unit. Dimers formed when crystals were grown in the presence of the non-cyclizable substrate analog 2',3'-dideoxyguanosine-5'-triphosphate, MnCl2, and tartrate, but their quaternary structure did not conform to the canonical pairing expected for class III enzymes. Moreover, the structure contained a disulfide bond formed with an active-site Cys residue required for activity. We consider it unlikely that the disulfide would form under intracellular reducing conditions, raising the possibility that this unusual dimer might have a biologically relevant role in the regulation of full-length RhoGC. Although we did not observe it with direct methods, a functional dimer was identified as the active state by following the dependence of activity on total enzyme concentration. The low affinity observed for GCRho monomers is unusual for this enzyme class and suggests that dimer formation may contribute to light activation of the full-length protein.


Asunto(s)
Guanilato Ciclasa/metabolismo , Optogenética/métodos , Rodopsina/metabolismo , Secuencia de Aminoácidos , Blastocladiella/metabolismo , Dominio Catalítico , GMP Cíclico/metabolismo , Escherichia coli/metabolismo , Proteínas de Escherichia coli/metabolismo , Nucleótidos Cíclicos/metabolismo , Dominios Proteicos , Transducción de Señal/fisiología
18.
J Hered ; 109(1): 78-89, 2017 12 21.
Artículo en Inglés | MEDLINE | ID: mdl-28992131

RESUMEN

Climate-associated clines in adaptive polymorphisms are commonly cited as evidence of local adaptation within species. However, the contribution of the clinally varying trait to overall fitness is often unknown. To address this question, we examined survival, vegetative growth, and reproductive output in a central US common garden experiment using 161 genotypes of white clover (Trifolium repens L.) originating from 15 locations across North America. White clover is polymorphic for cyanogenesis (hydrogen cyanide release upon tissue damage), a chemical defense against generalist herbivores, and climate-associated cyanogenesis clines have repeatedly evolved across the species range. Over a 12-month experiment, we observed striking correlations between the population of origin and plant performance in the common garden, with climatic distance from the common garden site predicting fitness more accurately than geographic distance. Assessments of herbivore leaf damage over the 2015 growing season indicated marginally lower herbivory on cyanogenic plants; however, this effect did not result in increased fitness in the common garden location. Linear mixed modeling suggested that while cyanogenesis variation had little predictive value for vegetative growth, it is as important as climatic variation for predicting reproductive output in the central United States. Together, our findings suggest that knowledge of climate similarity, as well as knowledge of locally favored adaptive traits, will help to inform transplantation strategies for restoration ecology and other conservation efforts in the face of climate change.


Asunto(s)
Adaptación Fisiológica/genética , Cambio Climático , Genética de Población , Trifolium/genética , Fertilidad , Aptitud Genética , Genotipo , Herbivoria , Cianuro de Hidrógeno/metabolismo , Modelos Lineales , América del Norte , Fenotipo
19.
Appl Opt ; 55(29): 8236-8247, 2016 Oct 10.
Artículo en Inglés | MEDLINE | ID: mdl-27828068

RESUMEN

A fast and accurate principal component-based radiative transfer model in the solar spectral region (PCRTM-SOLAR) has been developed. The algorithm is capable of simulating reflected solar spectra in both clear sky and cloudy atmospheric conditions. Multiple scattering of the solar beam by the multilayer clouds and aerosols are calculated using a discrete ordinate radiative transfer scheme. The PCRTM-SOLAR model can be trained to simulate top-of-atmosphere radiance or reflectance spectra with spectral resolution ranging from 1 cm-1 resolution to a few nanometers. Broadband radiances or reflectance can also be calculated if desired. The current version of the PCRTM-SOLAR covers a spectral range from 300 to 2500 nm. The model is valid for solar zenith angles ranging from 0 to 80 deg, the instrument view zenith angles ranging from 0 to 70 deg, and the relative azimuthal angles ranging from 0 to 360 deg. Depending on the number of spectral channels, the speed of the current version of PCRTM-SOLAR is a few hundred to over one thousand times faster than the medium speed correlated-k option MODTRAN5. The absolute RMS error in channel radiance is smaller than 10-3 mW/cm2/sr/cm-1 and the relative error is typically less than 0.2%.

20.
ACS Cent Sci ; 10(6): 1276-1282, 2024 Jun 26.
Artículo en Inglés | MEDLINE | ID: mdl-38947197

RESUMEN

Directing groups guide substitution patterns in organic synthetic schemes, but little is known about pathways to control reactivity patterns, such as regioselectivity, in complex inorganic systems such as bioinorganic cofactors or extended surfaces. Interadsorbate effects are known to encode surface reactivity patterns in inorganic materials, modulating the location and binding strength of ligands. However, owing to limited experimental resolution into complex inorganic structures, there is little opportunity to resolve these effects on the atomic scale. Here, we utilize an atomically precise Fe/Co/Se nanocluster platform, [Fe3(L)2Co6Se8L'6]+ ([1(L)2]+; L = CN t Bu, THF; L' = Ph2PN(-)Tol), in which allosteric interadsorbate effects give rise to pronounced site-differentiation. Using a combination of spectroscopic techniques and single-crystal X-ray diffractometry, we discover that coordination of THF at the ligand-free Fe site in [1(CN t Bu)2]+ sets off a domino effect wherein allosteric through-cluster interactions promote the regioselective dissociation of CN t Bu at a neighboring Fe site. Computational analysis reveals that this active site correlation is a result of delocalized Fe···Se···Co···Se covalent interactions that intertwine edge sites on the same cluster face. This study provides an unprecedented atom-scale glimpse into how interfacial metal-support interactions mediate a collective and regiospecific path for substrate exchange across multiple active sites.

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