Solution Structure and Intermolecular Interactions of the Third Metal-binding Domain of ATP7A, the Menkes Disease Protein

The third metal-binding domain of the human Menkes protein (MNK3), a copper(I)-transporting ATPase, has been expressed in Escherichia coli and characterized in solution. The solution structure of MNK3, its copper(I)-binding properties, and its interaction with the physiological partner, HAH1, have been studied. MNK3 is the domain most dissimilar in structure from the other domains of the Menkes protein. This is reflected in a significant rearrangement of the last strand of the four-stranded beta-sheet when compared with the other known homologous proteins or protein domains. MNK3 is also peculiar with respect to its interaction with the copper(I) ion, as it was found to be a comparatively weak binder. Copper(I) transfer from metal-loaded HAH1 was observed experimentally, but the metal distribution was shifted toward binding by HAH1. This is at variance with what is observed for the other Menkes domains

Draft genome sequence of Clostridium difficile belonging to ribotype 018 and sequence type 17

Clostridium difficile, belonging to ribotype 018 (RT018), is one of the most prevalent genotypes circulating in hospital settings in Italy. Here, we report the draft genome of C. difficile CD8-15 belonging to RT018, isolated from a patient with fatal C. difficile-associated infection

Copper(I)-mediated protein-protein interactions result from suboptimal interaction surfaces

International audienceThe homeostasis of metal ions in cells is the result of the contribution of several cellular pathways that involve transient, often weak, protein-protein interactions. Metal transfer typically implies the formation of adducts where the metal itself acts as a bridge between proteins, by coordinating residues of both interacting partners. Here we addressed the interaction between the human copper(I)-chaperone HAH1 and one metal-binding domain of one of its partners, namely the P-type copper-transporting ATPase ATP7A. The adduct was structurally characterized in solution, in the presence of copper(I), and through X-ray crystallography, upon replacing copper(I) with cadmium(II). Further insight was obtained through molecular modelling techniques and site-directed mutagenesis. It is found that the interaction involves a relatively small interface (less than 1000 Å2) with a low fraction of non-polar atoms. These observations provide a possible explanation for the low affinity of the two apo-proteins. It appears that electrostatics is important in selecting which domain of the ATPase is able to form detectable amounts of the metal-mediatd adduct with HAH1

Complete Blood Count as point of care testing QBC STAR\u2122: Preliminary evaluation

Introduction: Point of care testing (POCT) represents a valuable option when laboratory data shall be urgently available for timely clinical management, with a turnaround time (TAT) that is unfeasible using conventional laboratory instrumentation. This study was aimed to compare the performance of QBC STAR\u2122 compared to Sysmex XN-module and the reference optical microscopy (OM) assessment. Material and methods: One hundred peripheral blood samples, collected in K3 EDTA tubes, and 50 capillary blood samples obtained by finger stick were analyzed with QBC STAR\u2122, Sysmex XN-module, and OM. Data were compared with Passing-Bablok regression and Bland-Altman plots. Results: The Passing-Bablok regression analysis (QBC STAR\u2122 capillary sample vs XN-module) yielded slopes comprised between 0.30 and 1.37, while the intercepts ranged between -17.57 and 232.6. Bland-Altman plots yielded relative bias comprised between -4.87% (for MN QBC STAR\u2122 capillary sample vs XN-module) and 27% (PLT QBC STAR\u2122 capillary sample vs XN-module). A significant bias was found for all parameters except MN and WBC, RBC in all and pediatric samples, and HB in adults samples. Conclusion: The results of this analytical evaluation suggest that QBC STAR\u2122 may not be the ideal tool for performing complete blood count analysis for diagnostic purposes, while it could be more useful in urgent/emergent conditions, such as for rapid monitoring of some hematological parameters (eg, WBC and HB)

Altered Proteolysis in Fibroblasts of Alzheimer Patients with Predictive Implications for Subjects at Risk of Disease

There is great interest in developing reliable biomarkers to support antemortem diagnosis of late-onset Alzheimer’s disease (AD). Early prediction and diagnosis of AD might be improved by the detection of a proteolytic dysfunction in extracts from cultured AD fibroblasts, producing altered isoelectrophoretic forms of the enzyme transketolase (TK-alkaline bands). The TK profile and apolipoprotein E (APOE) genotype were examined in fibroblasts from 36 clinically diagnosed probable late-onset sporadic AD patients and 38 of their asymptomatic relatives, 29 elderly healthy individuals, 12 neurological non-AD patients, and 5 early-onset AD patients. TK alterations occurred in (i) several probable AD patients regardless of age-of-onset and severity of disease; (ii) all early-onset AD patients and APOE ε4/4 carriers; and (iii) nearly half of asymptomatic AD relatives. Normal subjects and non-AD patients were all negative. Notably, culture conditions promoting TK alterations were also effective in increasing active BACE1 levels. Overall, the TK assay might represent a low-cost laboratory tool useful for supporting AD differential diagnosis and identifying asymptomatic subjects who are at greater risk of AD and who should enter a follow-up study. Moreover, the cultured fibroblasts were confirmed as a useful in vitro model for further studies on the pathogenetic process of AD

Not Only Diagnostic Yield: Whole-Exome Sequencing in Infantile Cardiomyopathies Impacts on Clinical and Family Management

Whole-exome sequencing (WES) is a powerful and comprehensive tool for the genetic diagnosis of rare diseases, but few reports describe its timely application and clinical impact on infantile cardiomyopathies (CM). We conducted a retrospective analysis of patients with infantile CMs who had trio (proband and parents)-WES to determine whether results contributed to clinical management in urgent and non-urgent settings. Twenty-nine out of 42 enrolled patients (69.0%) received a definitive molecular diagnosis. The mean time-to-diagnosis was 9.7 days in urgent settings, and 17 out of 24 patients (70.8%) obtained an etiological classification. In non-urgent settings, the mean time-to-diagnosis was 225 days, and 12 out of 18 patients (66.7%) had a molecular diagnosis. In 37 out of 42 patients (88.1%), the genetic findings contributed to clinical management, including heart transplantation, palliative care, or medical treatment, independent of the patient’s critical condition. All 29 patients and families with a definitive diagnosis received specific counseling about recurrence risk, and in seven (24.1%) cases, the result facilitated diagnosis in parents or siblings. In conclusion, genetic diagnosis significantly contributes to patients’ clinical and family management, and trio-WES should be performed promptly to be an essential part of care in infantile cardiomyopathy, maximizing its clinical utility