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We introduce a Markov Modulated Process (MMP) to describe human mobility. We represent the mobility process as a time-varying graph, where a link specifies a connection between two nodes (humans) at any discrete time step. Each state of the Markov chain encodes a certain modification to the original graph. We show that our MMP model successfully captures the main features of a random mobility simulator, in which nodes moves in a square region. We apply our MMP model to human mobility, measured in a library.

Background: Safinamide modulates both dopaminergic and glutamatergic systems with positive effects on motor and non-motor symptoms of Parkinson's disease (PD). The drug utilization study SYNAPSES was designed to investigate the use of safinamide in routine clinical practice, as recommended by the European Medicines Agency. Objective: To describe the occurrence of adverse events in PD patients treated with safinamide in real-life conditions. Methods: The SYNAPSES trial is an observational, European, multicenter, retrospective-prospective cohort study. Patients were followed up to 12 months with analyses performed in the overall population and in patients aged >75 years, with relevant comorbidities and with psychiatric conditions. Results: Of the 1610 patients included, 82.4% were evaluable after 12 months with 25.1% of patients >75 years, 70.8% with relevant comorbidities and 42.4% with psychiatric conditions. During observation 45.8% patients experienced adverse events, 27.7% patients had adverse drug reactions and 9.2% patients had serious adverse events. The adverse events were those already described in the patients' information leaflet. The majority were mild or moderate and completely resolved and no differences were detected between the subgroup of patients. Clinically significant improvements were seen in the UPDRS motor score and in the UPDRS total score in >= 40% of patients, according to the criteria developed by Shulman et al. Conclusion: The SYNAPSES study confirms the good safety profile of safinamide even in special groups of patients. Motor complications and motor scores improved with clinically significant results in the UPDRS scale maintained in the long-term.

In multiple myeloma, novel treatments with proteasome inhibitors (PIs) and immunomodulatory agents (IMiDs) have prolonged survival but the disease remains incurable. At relapse, next-generation sequencing has shown occasional mutations of drug targets but has failed to identify unifying features that underlie chemotherapy resistance. We studied 42 patients refractory to both PIs and IMiDs. Whole-exome sequencing was performed in 40 patients, and RNA sequencing (RNA-seq) was performed in 27. We found more mutations than were reported at diagnosis and more subclonal mutations, which implies ongoing evolution of the genome of myeloma cells during treatment. The mutational landscape was different from that described in published studies on samples taken at diagnosis. The TP53 pathway was the most frequently inactivated (in 45% of patients). Conversely, point mutations of genes associated with resistance to IMiDs were rare and were always subclonal. Refractory patients were uniquely characterized by having a mutational signature linked to exposure to alkylating agents, whose role in chemotherapy resistance and disease progression remains to be elucidated. RNA-seq analysis showed that treatment or mutations had no influence on clustering, which was instead influenced by karyotypic events. We describe a cluster with both amp(1q) and del(13) characterized by CCND2 upregulation and also overexpression of MCL1, which represents a novel target for experimental treatments. Overall, high-risk features were found in 65% of patients. However, only amp(1q) predicted survival. Gene mutations of IMiD and PI targets are not a preferred mode of drug resistance in myeloma. Chemotherapy resistance of the bulk tumor population is likely attained through differential, yet converging evolution of subclones that are overall variable from patient to patient and within the same patient. © 2020 by The American Society of Hematology.

Hydrogenases are enzymes that catalyze hydrogen oxidation and production. The so-called "FeFe hydrogenases", the active site of which is a [Fe6(CN)2(CO)3] cluster, are particularly efficient. Their inhibition by O2 prevents them from being used for H2 production. Combining electrochemical experiments, site-directed mutagenesis, molecular dynamics calculations and quantum chemistry calculations allowed to elucidate all steps of the reaction with O2 and to predict the rate of inhibition. These results will pave the way for engineering enzymes that resist O2.

Objectives To report the results of a national survey aimed at quantifying the current level of diffusion of Levodopa/carbidopa intestinal gel (LCIG) in Italy. Methods Sixty Parkinson's Disease (PD) specialists in Italy were invited to complete a survey covering issues on clinical and practical aspects of LCIG therapy. Results Clinical features of 905 patients were collected retrospectively. The majority of centres reported the use of a multidisciplinary team, biochemistry testing, neurophysiological and neuropsychological tests before and after treatment, in addition to caregivers' training and patient's follow as outpatients. Most centres (60%) used internal guidelines for patient selection. The overall rate of adverse events was 55.1%. Weight loss, chronic polyneuropathy and stoma infection were the most frequently reported. 40% of centres used replacement therapy with Vitamin B12 and Folic acid from the start of LCIG and continued this for the duration of treatment. The rate of discontinuation was of 25.7% overall, with 9.5% of cases occurring in the first year. The main causes of withdrawal were device-related complications, disease progression (comorbidity, severe dementia) and caregiver and/or patient dissatisfaction. Conclusions In Italy LCIG infusion is managed in a uniform manner at a clinical, practical and organizational level even though the selection criteria are not standardized through the country. The high percentage of patients remaining on treatment in the short- and long-term follow-up confirms effectiveness of treatment, careful follow-up, and appropriate patient and caregivers training.

Background Targeted therapy with BRAF and MEK inhibitors has improved the survival of patients with BRAF-mutated metastatic melanoma, but most patients relapse upon the onset of drug resistance induced by mechanisms including genetic and epigenetic events. Among the epigenetic alterations, microRNA perturbation is associated with the development of kinase inhibitor resistance. Here, we identified and studied the role of miR-146a-5p dysregulation in melanoma drug resistance. Methods The miR-146a-5p-regulated NFkB signaling network was identified in drug-resistant cell lines and melanoma tumor samples by expression profiling and knock-in and knock-out studies. A bioinformatic data analysis identified COX2 as a central gene regulated by miR-146a-5p and NFkB. The effects of miR-146a-5p/COX2 manipulation were studied in vitro in cell lines and with 3D cultures of treatment-resistant tumor explants from patients progressing during therapy. Results miR-146a-5p expression was inversely correlated with drug sensitivity and COX2 expression and was reduced in BRAF and MEK inhibitor-resistant melanoma cells and tissues. Forced miR-146a-5p expression reduced COX2 activity and significantly increased drug sensitivity by hampering prosurvival NFkB signaling, leading to reduced proliferation and enhanced apoptosis. Similar effects were obtained by inhibiting COX2 by celecoxib, a clinically approved COX2 inhibitor. Conclusions Deregulation of the miR-146a-5p/COX2 axis occurs in the development of melanoma resistance to targeted drugs in melanoma patients. This finding reveals novel targets for more effective combination treatment. Graphical Abstract

Hydrogenases are enzymes that catalyze the oxidation and production of molecular hydrogen. For about fifteen years, there have been many reports about the successful connection of these enzymes to photosensitizers with the aim of designing H2 photoproduction systems, but relatively little attention has been paid to whether and why illumination may affect the catalytic properties of the enzyme. In all hydrogenases, hydrogen activation occurs at an inorganic active site that includes at least one Fe-carbonyl motif, which may make it sensitive to irradiation. Here we review the evidence that hydrogenases are indeed photosensitive. We focus mainly on the so-called FeFe hydrogenases; their active site, called the H-cluster, consists of a [4Fe4S] cluster that is bound by a cysteine sulfur to a diiron site. The iron atoms of the binuclear cluster are coordinated by carbonyl and cyanide ligands and an azadithiolate group. We describe the effects of UV-visible light irradiation on the enzyme under cryogenic or turnover conditions and the photoreactivity of model complexes that mimic the diiron site. We emphasize the dependence of the photochemical processes on wavelength, and warn about FeFe hydrogenase photoinhibition, which should probably be considered when attempts are made to use FeFe hydrogenases for the artificial photosynthesis of solar fuels. We also underline the relevance of studies of synthetic mimics of the H-cluster for understanding at atomistic level the photochemical processes observed in the enzyme.

In view of the depletion of fossil fuel reserves and climatic effects of greenhouse gas emissions, Ni,Fe-containing carbon monoxide dehydrogenase (Ni-CODH) enzymes have attracted increasing interest in recent years for their capability to selectively catalyze the reversible reduction of CO2 to CO (CO2 + 2H+ + 2e- ⇌ CO + H2O). The possibility of converting the greenhouse gas CO2 into useful materials that can be used as synthetic building blocks or, remarkably, as carbon fuels makes Ni-CODH a very promising target for reverse-engineering studies. In this context, in order to provide insights into the chemical principles underlying the biological catalysis of CO2 activation and reduction, quantum mechanics calculations have been carried out in the framework of density functional theory (DFT) on different-sized models of the Ni-CODH active site. With the aim of uncovering which stereoelectronic properties of the active site (known as the C-cluster) are crucial for the efficient binding and release of CO2, different coordination modes of CO2 to different forms and redox states of the C-cluster have been investigated. The results obtained from this study highlight the key role of the protein environment in tuning the reactivity and the geometry of the C-cluster. In particular, the protonation state of His93 is found to be crucial for promoting the binding or the dissociation of CO2. The oxidation state of the C-cluster is also shown to be critical. CO2 binds to Cred2 according to a dissociative mechanism (i.e., CO2 binds to the C-cluster after the release of possible ligands from Feu) when His93 is doubly protonated. CO2 can also bind noncatalytically to Cred1 according to an associative mechanism (i.e., CO2 binding is preceded by the binding of H2O to Feu). Conversely, CO2 dissociates when His93 is singly protonated and the C-cluster is oxidized at least to the Cint redox state.

A general single-step approach is introduced for the green fabrication of hybrid biosensors from water dispersion. The resulting device integrates the semiconducting properties of a carbon nanotube (CNT) and the functionality of a protein. In the initial aqueous phase, the protein (viz., lysozyme [LZ]) disperses the (6,5)CNT. Drop-casting of the dispersion on a test pattern (a silicon wafer with interdigitated Au source and drain electrodes) yields a fully operating, robust, electrolyte-gated transistor (EGT) in one step. The EGT response to biorecognition is then assessed using the LZ inhibitorN-acetyl glucosamine trisaccharide. Analysis of the output signal allows one to extract a protein-substrate binding constant in line with values reported for the free (without CNT) system. The methodology is robust, easy to optimize, redirectable toward different targets and sets the grounds for a new class of CNT-protein biosensors that overcome many limitations of the technology of fabrication of CNT biosensors

In multiple myeloma, novel treatments with proteasome inhibitors (PIs) and immunomodulatory agents (IMiDs) have prolonged survival but the disease remains incurable. At relapse, next-generation sequencing has shown occasional mutations of drug targets but has failed to identify unifying features that underlie chemotherapy resistance. We studied 42 patients refractory to both PIs and IMiDs. Whole-exome sequencing was performed in 40 patients, and RNA sequencing (RNA-seq) was performed in 27. We found more mutations than were reported at diagnosis and more subclonal mutations, which implies ongoing evolution of the genome of myeloma cells during treatment. The mutational landscape was different from that described in published studies on samples taken at diagnosis. The TP53 pathway was the most frequently inactivated (in 45% of patients). Conversely, point mutations of genes associated with resistance to IMiDs were rare and were always subclonal. Refractory patients were uniquely characterized by having a mutational signature linked to exposure to alkylating agents, whose role in chemotherapy resistance and disease progression remains to be elucidated. RNA-seq analysis showed that treatment or mutations had no influence on clustering, which was instead influenced by karyotypic events. We describe a cluster with both amp(1q) and del(13) characterized by CCND2 upregulation and also overexpression of MCL1, which represents a novel target for experimental treatments. Overall, high-risk features were found in 65% of patients. However, only amp(1q) predicted survival. Gene mutations of IMiD and PI targets are not a preferred mode of drug resistance in myeloma. Chemotherapy resistance of the bulk tumor population is likely attained through differential, yet converging evolution of subclones that are overall variable from patient to patient and within the same patient.

The TANDEM investigation was carried out in 17 Italian Movement Disorder centers on behalf of a joint initiative of neurologist members of the Italian Academy for Parkinson’s disease and Movement Disorders (LIMPE-DISMOV Academy) and gastroenterologist members of the Italian Society of Digestive Endoscopy (SIED) to evaluate the efficacy and tolerability of levodopa-carbidopa intestinal gel (LCIG) in patients with advanced Parkinson's disease (PD) in routine medical care. Motor scores in “ON” and OFF” state (UPDRS-III), complications of therapy (UPDRS-IV), activities of daily living, sleep disorders and quality of life were evaluated at baseline and at two follow-up assessments (FUV1 and FUV2) within the initial 12-month LCIG treatment. In 159 patients (55% males) with a mean age of 69.1 ± 6.6years and a diagnosis of PD since 13.6 ± 5.5years, the UPDRS-III total score (in “OFF”) decreased from baseline (45.8 ± 13.2) to FUV1 (41.0 ± 17.4; p < 0.001) and FUV2 (40.5 ± 15.5; p < 0.001), the UPDRS-IV total score decreased from baseline (8.8 ± 2.9) to FUV1 (5.1 ± 3.4; p < 0.001) and FUV2 (5.5 ± 3.2; p < 0.001). The percentage of patients exhibiting freezing, dystonia, gait/walking disturbances, falls, pain and sleep disorders was significantly reduced. Twenty-eight device complications were reported and 11 (6.9%) patients prematurely terminated the study. LCIG after 12-month treatment led to sustained improvement of time spent in “OFF”, complications of therapy, PD-associated symptoms and sleep disorders. LCIG tolerability was consistent with the established safety profile of LCIG.

International audience; FeFe hydrogenases catalyse H2 oxidation and production using a "H-cluster", where two Fe ions are bound by an aza-dithiolate (adt) ligand. Various hypotheses have been proposed (by us and others) to explain that the enzyme reversibly inactivates under oxidizing, anaerobic conditions: intramolecular binding of the N atom of adt, formation of the so-called Hox/inact state or non-productive binding of H2 to isomers of the H-cluster. Here we show that none of the above explains the new finding that the anaerobic, oxidative, H2-dependent reversible inactivation is strictly dependent on the presence of Cl- or Br-. We provide experimental evidence that chloride uncompetitively inhibits the enzyme: it reversibly binds to catalytic intermediates of H2 oxidation (but not to the resting "Hox" state), after which oxidation locks the active site into a stable, saturated, inactive form, the structure of which is proposed here based on DFT calculations. The halides interact with the amine group of the H-cluster but do not directly bind to iron. It should be possible to stabilize the inhibited state in amounts compatible with spectroscopic investigations to explore further this unexpected reactivity of the H-cluster of hydrogenase.

International audience; Electrochemical studies of hydrogenases, the biological catalysts of H 2 oxidation and production, have proven wrong the old saying that enzymes do not easily transfer electrons to electrodes in the absence of mediators. Many distinct hydrogenases have actually been directly connected to electrodes or particles, for studying their catalytic mechanism or for designing solar fuels catalysts. In this review, we list the electrodes that have proved successful for direct electron transfer to hydrogenases, and we discuss recent results which illustrate new directions in this research field: the study of the biosynthesis of FeFe hydrogenase, the electrochemical characterization of non-standard NiFe-or FeFe hydrogenases, the general discussion of what makes a catalyst better in one particular direction of the reaction, and the elucidation of the molecular mechanism of hydrogenase catalysis by combining electrochemistry and theoretical chemistry, spectroscopy or photochemistry. The electrochem-ical methods described herein will probably prove useful for studying or using other redox enzymes.

Simple Summary The treatment of collecting duct carcinoma (CDC) remains unsatisfactory since this highly aggressive kidney cancer has an unfavorable clinical behavior. Due to the rarity of CDC a complete biological characterization of this disease is still lacking. The aim of our study is to provide new insights into the molecular biology of CDC leveraging newly generated and publicly available gene expression profiles of CDC tumors. We identified unique gene expression programs and pathways that distinguished CDC from other renal malignancies. The CDC-specific expression signature predicted in vitro sensitivity to several small molecule inhibitors screened in cancer cell lines from multiple cancer types. Finally, we proved that CDC is a molecularly heterogeneous disease made up of at least two subtypes distinguished by cell signaling, metabolic and immune-related alterations. Altogether, these findings pave the way for future investigations with meaningful clinical implications aimed at improving the management of CDC patients. Abstract Collecting duct carcinoma (CDC) is a rare and highly aggressive kidney cancer subtype with poor prognosis and no standard treatments. To date, only a few studies have examined the transcriptomic portrait of CDC. Through integration of multiple datasets, we compared CDC to normal tissue, upper-tract urothelial carcinomas, and other renal cancers, including clear cell, papillary, and chromophobe histologies. Association between CDC gene expression signatures and in vitro drug sensitivity data was evaluated using the Cancer Therapeutic Response Portal, Genomics of Drug Sensitivity in Cancer datasets, and connectivity map. We identified a CDC-specific gene signature that predicted in vitro sensitivity to different targeted agents and was associated to worse outcome in clear cell renal cell carcinoma. We showed that CDC are transcriptionally related to the principal cells of the collecting ducts providing evidence that this tumor originates from this normal kidney cell type. Finally, we proved that CDC is a molecularly heterogeneous disease composed of at least two subtypes distinguished by cell signaling, metabolic and immune-related alterations. Our findings elucidate the molecular features of CDC providing novel biological and clinical insights. The identification of distinct CDC subtypes and their transcriptomic traits provides the rationale for patient stratification and alternative therapeutic approaches.

International audience; FeFe hydrogenases are the most efficient H2-producing enzymes. However, inactivation by O2 remains an obstacle that prevents them being used in many biotechnological devices. Here, we combine electrochemistry, site-directed mutagenesis, molecular dynamics and quantum chemical calculations to uncover the molecular mechanism of O2 diffusion within the enzyme and its reactions at the active site. We propose that the partial reversibility of the reaction with O2 results from the four-electron reduction of O2 to water. The third electron/proton transfer step is the bottleneck for water production, competing with formation of a highly reactive OH radical and hydroxylated cysteine. The rapid delivery of electrons and protons to the active site is therefore crucial to prevent the accumulation of these aggressive species during prolonged O2 exposure. These findings should provide important clues for the design of hydrogenase mutants with increased resistance to oxidative damage.

Conspectus Many enzymes that produce or transform small molecules such as O2, H2, and CO2 embed inorganic cofactors based on transition metals. Their active site, where the chemical reaction occurs, is buried in and protected by the protein matrix, and connected to the solvent in several ways: chains of redox cofactors mediate long-range electron transfer; static or dynamic tunnels guide the substrate, product and inhibitors; amino acids and water molecules transfer protons. The catalytic mechanism of these enzymes is therefore delocalized over the protein and involves many different steps, some of which determine the response of the enzyme under conditions of stress (extreme redox conditions, presence of inhibitors, light), the catalytic rates in the two directions of the reaction and their ratio (the "catalytic bias"). Understanding all the steps in the catalytic cycle, including those that occur on sites of the protein that are remote from the active site, requires a combination of biochemical, structural, spectroscopic, theoretical, and kinetic methods. Here we argue that kinetics should be used to the fullest extent, by extracting quantitative information from the comparison of data and kinetic models and by exploring the combination of experimental kinetics and theoretical chemistry. In studies of these catalytic mechanisms, direct electrochemistry, the technique which we use and contribute to develop, has become unescapable. It simply consists in monitoring the changes in activity of an enzyme that is wired to an electrode by recording an electric current. We have described kinetic models that can be used to make sense of these data and to learn about various aspects of the mechanism that are difficult to probe using more conventional methods: long-range electron transfer, diffusion along gas channels, redox-driven (in)activations, active site chemistry and photoreactivity under conditions of turnover. In this Account, we highlight a few results that illustrate our approach. We describe how electrochemistry can be used to monitor substrate and inhibitor diffusion along the gas channels of hydrogenases and we discuss how the kinetics of intramolecular diffusion relates to global properties such as resistance to oxygen and catalytic bias. The kinetics and/or thermodynamics of intramolecular electron transfer may also affect the catalytic bias, the catalytic potentials on either side of the equilibrium potential, and the overpotentials for catalysis (defined as the difference between the catalytic potentials and the open circuit potential). This is understood by modeling the shape of the steady-state catalytic response of the enzyme. Other determinants of the catalytic rate, such as domain motions, have been probed by examining the transient catalytic response recorded at fast scan rates. Last, we show that combining electrochemical investigations and MD, DFT, and TD-DFT calculations is an original way of probing the reactivity of the H-cluster of hydrogenase, in particular its reactions with CO, O2, and light. This approach contrasts with the usual strategy which aims at stabilizing species that are presumed to be catalytic intermediates, and determining their structure using spectroscopic or structural methods.

Le FeFe idrogenasi sono metalloenzimi che catalizzano l’ossidazione e la produzione di H2. Il ciclo catalitico e vari aspetti di questi enzimi, come l’inattivazione in condizioni aerobiche e anaerobiche, sono tutt’ora oggetto di studio. Per ottenere informazioni sulla struttura elettronica del sito attivo delle FeFe idrogenasi vengono abitualmente impiegate tecniche spettroscopiche, grazie alle quali viene determinato l’assorbimento di luce a diverse lunghezze d’onda da parte dell’enzima. In questa tesi, invece, abbiamo sviluppato una nuova tecnica, detta “fotoelettrochimica diretta”, in cui l’enzima è direttamente collegato ad un elettrodo, che può essere illuminato da una sorgente luminosa, e la frequenza di turnover viene direttamente misurata sotto forma di corrente elettrica. Monitorando le variazioni dell’attività dell’enzima in presenza di irraggiamento, possiamo determinare l’assorbimento del sito attivo in funzione della lunghezza d’onda e della potenza della sorgente luminosa. Concentrandoci sulle variazioni della frequenza di turnover, siamo certi che stiamo indagando l’effetto della luce localizzato sul sito attivo. Abbiamo utilizzato la fotoelettrochimica diretta per studiare l’effetto dell'irraggiamento, per mezzo di laser monocromatici, sulla cinetica di inibizione da CO in tre distinte FeFe idrogenasi. Abbiamo determinato lo spettro d’azione della fotodissociazione del CO inibitore e abbiamo descritto il processo a livello QM per la prima volta, ottenendo un buon accordo tra dati sperimentali e teorici. Ci siamo poi focalizzati sullo studio della fotoinibizione dell’enzima. Tramite esperimenti di fotoelettrochimica, in cui la proteina è stata illuminata per mezzo di laser monocromatici, una lampada alogena o una lampada allo xeno, abbiamo determinato che le FeFe idrogenasi di C. reinhardtii e C. acetobutylicum sono inattivate irreversibilmente dai raggi UVB. Utilizzando DFT e TDDFT, abbiamo concluso che le fasi iniziali della fotoinibizione consistono nella fotodissociazione di uno dei carbonili intrinsecamente legati al sito attivo, seguita dalla formazione di specie stabili inattive. Infine, abbiamo condotti esperimenti preliminari per esaminare l’effetto della luce sull’attività di altri due metalloenzimi: la monossido di carbonio deidrogenasi (CODH) e la NiFe idrogenasi. L’attività catalitica della CODH non viene alterata dall’illuminazione, mentre la riattivazione dell’enzima, in seguito ad esposizione all’ossigeno, è più rapida in presenza di illuminazione con una lampada allo xeno. Inoltre, la NiFe idrogenasi, in una forma inattiva, si riattiva più rapidamente in presenza di irraggiamento con un laser violetto/blu che al buio. I risultati dimostrano la solidità di questo approccio metodologico, che combina elettrochimica diretta e TDDFT, e forniscono nuove informazioni sulle proprietà chimiche e fotochimiche di vari metalloenzimi. FeFe hydrogenases are metalloenzymes that catalyze the oxidation and production of H2. The catalytic cycle and many aspects of the reactivity of these enzymes, including their aerobic and anaerobic inactivation, are still the subjects of intense investigations. Spectroscopy is commonly used to obtain information on the electronic structure of the active site of FeFe hydrogenases, by determining the absorption of the enzyme at different wavelengths. In contrast, in this thesis, I propose to use in this context a new technique which we have called "direct photoelectrochemistry", whereby the enzyme is directly wired to an electrode which can be irradiated with a light source, and the turnover frequency is measured as a current. We can detect the absorption of the active site as a function of light wavelength and power by monitoring changes in reactivity upon irradiation. Focusing on the variations of turnover rate, we are sure that we are studying the effect of light on catalytic intermediates. I used direct photo-electrochemistry to study the effect of monochromatic irradiation in the visible range on the kinetics of inhibition by CO of three distinct FeFe hydrogenases. I determined the action spectrum of the photo-dissociation of the inhibitor CO and I described the process at the QM level for the first time, obtaining good agreement between experiments and theory. I also studied the photoinhibition of the enzyme. I carried out photoelectrochemistry experiments irradiating the protein with monochromatic visible light laser diodes, a halogen lamp or a xenon lamp, and I observed that the FeFe hydrogenases from C. reinhardtii and C. acetobutylicum are irreversibly inactivated by UVB light. Using DFT and TDDFT, I concluded that the initial steps of photoinhibition consist in the photodissociation of one carbonyl intrinsic ligand of the active site, followed by the formation of a stable inactive species. I also performed preliminary experiments to examine the effect of light on the activity of two other metalloenzymes: Carbon monoxide dehydrogenase (CODH) and NiFe-hydrogenase. I observed that the turnover rate of CODH is not affected by light, but the reactivation of the enzyme after exposure to oxygen is faster upon irradiation with white light. I also showed that the oxidized, inactive form of NiFe-hydrogenase reactivates more quickly upon irradiation with violet/blue light than in the dark. My results illustrate the strength of the methodological approach that combines direct electrochemistry and TDDFT, and reveal new insights in the chemical and photochemical properties of several metalloenzymes.

Introduction: Caring for a person with Parkinson’s disease (PD) is associated with an increased risk of psychiatric morbidity and persistent distress. The objective of this study was to describe the burden and the related factors of caregivers of advanced PD (APD) patients either treated with continuous dopaminergic delivery systems or standard therapy. Methods: This cross-sectional, epidemiologic study conducted in 13 Italian sites enrolled PD patients treated with continuous dopaminergic delivering systems [either levodopa/carbidopa intestinal gel (LCIG) infusion or continuous subcutaneous apomorphine infusion (CSAI)] or continuation of standard of care (SOC) with a caregiver. Patient quality of life (QoL) and caregiver burden were assessed using the Parkinson’s Disease Questionnaire (PDQ-8) and Zarit Burden Inventory (ZBI), respectively. Results: 126 patients (mean age 69.3 ± 8years) and their caregivers (mean age 57.9 ± 12.9) were enrolled. Most caregivers were spouses. Fifty-three patients were treated with LCIG, 19 with CSAI, and 54 with SOC. Mean ZBI scores were 29.6 ± 14.4 for LCIG, 35.8 ± 20.2 for CSAI, and 31.4 ± 16.0 for SOC. Caregivers of LCIG, CSAI, and SOC patients showed no burden or mild/moderate burden in 74, 53, and 63% of the cases, respectively. Mean PDQ-8 scores were 11.25 ± 5.67, 11.26 ± 5.55, and 14.22 ± 6.51 in LCIG, CSAI, and SOC patients. Neurologists considered patients “very much or much improved” in 89, 58, and 13% of the LCIG, CSAI, and SOC groups using the Clinical Global Impression–Global Improvement Scale. Predictors significantly associated with caregiver burden were patients and caregivers’ judgment of QoL and caregivers’ need to change work. Conclusions: Caregiver burden showed a tendency to be lower when patients are treated with LCIG than with CSAI or SOC.

International audience; FeFe hydrogenases catalyze H-2 oxidation and formation at an inorganic active site (the "H-cluster"), which consists of a [Fe-2(CO)(3)(CN)(2)(dithiomethylamine)] subcluster covalently attached to a Fe4S4 subcluster. This active site is photosensitive: visible light has been shown to induce the release of exogenous CO (a reversible inhibitor of the enzyme), shuffle the intrinsic CO ligands, and even destroy the H-cluster. These reactions must be understood because they may negatively impact the Use of hydrogenase for the photoproduction of H-2. Here, we explore in great detail the reactivity of the excited states of the H-duster under catalytic conditions by examining, both experimentally and using TDDFT calculations, the simplest photochemical reaction: the binding and release of exogenous CO. A simple dyad model can be used to predict which excitations are active. This could be used for probing other, aspects of the photoreactivity of the H-cluster.