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Since 1993, when the structure of Escherichia coli type II l -asparaginase (EcAII) in complex with l -aspartate was firstly reported, many structures of the wild type and mutated enzyme have been deposited in the Protein Data Bank. None of them report the full structure of the monomer in its ligand-free, open conformation, mainly because of the high dynamic and flexibility of the active site flexible loop. Here we report for the first time the structure of EcAII wild type in its open conformation comprising, for at least one protomer, clear electron density for the active site flexible loop (PDB ID: 6YZI). The structural element is highly mobile and it is transposed onto the rigid part of the active site upon substrate binding to allow completion of the enzyme catalytic center, thanks to key residues that serve as hinges and anchoring points. In the substrate binding pocket, several highly conserved water molecules are coordinated by residues involved in substrate binding, comprising two water molecules very likely involved in the enzyme catalytic process. We also describe, by molecular dynamics simulations, how the transposition of the loop, besides providing the proximity of residues needed for catalysis, causes a general stabilization of the protein.

Approximately 40–60% of falls in the elderly lead to injuries, resulting in disability and loss of independence. Despite the higher prevalence of falls and morbidity rates in cognitively impaired individuals, most fall risk assessments fail to account for mental status. In addition, successful fall prevention programmes in cognitively normal adults have generally failed in patients with cognitive impairment. Identifying the role of pathological aging on fall characteristics can improve the sensitivity and specificity of fall prevention approaches. This literature review provides a thorough investigation into fall prevalence and fall risk factors, the accuracy of fall risk assessments, and the efficacy of fall prevention strategies in individuals with diverse cognitive profiles. We show that fall-related characteristics differ between cognitive disorders and fall risk assessment tools as well as fall prevention strategies should critically consider each patient’s cognitive status to facilitate the identification of fallers at an earlier stage and support clinical decision-making.

Understanding how local protein modifications, such as binding small-molecule ligands, can trigger and regulate large-scale motions of large protein domains is a major open issue in molecular biology. We address various aspects of this problem by analyzing and comparing atomistic simulations of Hsp90 family representatives for which crystal structures of the full length protein are available: mammalian Grp94, yeast Hsp90 and E.coli HtpG. These chaperones are studied in complex with the natural ligands ATP, ADP and in the Apo state. Common key aspects of their functional dynamics are elucidated with a novel multi-scale comparison of their internal dynamics. Starting from the atomic resolution investigation of internal fluctuations and geometric strain patterns, a novel analysis of domain dynamics is developed. The results reveal that the ligand-dependent structural modulations mostly consist of relative rigid-like movements of a limited number of quasi-rigid domains, shared by the three proteins. Two common primary hinges for such movements are identified. The first hinge, whose functional role has been demonstrated by several experimental approaches, is located at the boundary between the N-terminal and Middle-domains. The second hinge is located at the end of a three-helix bundle in the Middle-domain and unfolds/unpacks going from the ATP- to the ADP-state. This latter site could represent a promising novel druggable allosteric site common to all chaperones.

Online data collection offers a wide range of benefits including access to larger and more diverse populations, together with a reduction in the experiment cycle. Here we compare performance in a spatial memory task, in which participants had to estimate object locations following viewpoint shifts, using data from a controlled lab-based setting and from an unsupervised online sample. We found that the data collected in a conventional laboratory setting and those collected online produced very similar results, although the online data was more variable with standard errors being about 10% larger than those of the data collected in the lab. Overall, our findings suggest that spatial memory studies using static images can be successfully carried out online with unsupervised samples. However, given the higher variability of the online data, it is recommended that the online sample size is increased to achieve similar standard errors to those obtained in the lab. For the current study and data processing procedures, this would require an online sample 25% larger than the lab sample.

Mitochondrial chaperonin Heat Shock Protein 60 kDa (Hsp60) oversees the correct folding of client proteins in cooperation with Hsp10. Hsp60 monomers M first form 7-meric Single rings ( S ), which then pair into 14-meric Double rings ( D ) that accommodate clients in their lumen. Recruitment of 7 Hsp10 molecules per pole yields a sealed 28-meric Football-shaped complex ( F ). ATP hydrolysis in each Hsp60 unit drives client folding and F disassembly. The V72I mutation in hereditary spastic paraplegia form SPG13 impairs Hsp60 function despite being distant from the active site. We here investigate this impairment with atomistic molecular dynamics (MD) simulations of M , S , D , and F for both WT and mutant Hsp60, considering catalytic aspartates in D and F in different protonation states (even simulating one such state of D post-hydrolysis). Our findings show that—as observed experimentally—V72I rigidifies Hsp60 assemblies, significantly impacting internal dynamics. In monomers, V72I introduces a new allosteric route that bypasses the ATP binding site and affects mechanisms driving reactivity. These insights highlight a multiscale complexity of Hsp60 that could inspire the design of experiments to better understand both its WT and V72I variants. Mutations cause impairment of function in the chaperone Hsp60. Here, the authors investigate their impact with MD simulations from the monomer to the 28-mer complex, and show the pervasive effects of mutations on functional dynamics across multiple scales.

Aerobic glycolysis in cancer cells, also known as the ‘Warburg effect’, is driven by hyperactivity of lactate dehydrogenase A (LDHA). LDHA is thought to be a substrate-regulated enzyme, but it is unclear whether a dedicated intracellular protein also regulates its activity. Here, we identify the human tumor suppressor folliculin (FLCN) as a binding partner and uncompetitive inhibitor of LDHA. A flexible loop within the amino terminus of FLCN controls movement of the LDHA active-site loop, tightly regulating its enzyme activity and, consequently, metabolic homeostasis in normal cells. Cancer cells that experience the Warburg effect show FLCN dissociation from LDHA. Treatment of these cells with a decapeptide derived from the FLCN loop region causes cell death. Our data suggest that the glycolytic shift of cancer cells is the result of FLCN inactivation or dissociation from LDHA. Together, FLCN-mediated inhibition of LDHA provides a new paradigm for the regulation of glycolysis. Identification of the tumor suppressor FLCN as an intracellular inhibitor of LDHA and a regulator of the Warburg effect provides a new paradigm for the regulation of glycolysis.

Binding of the mitochondrial chaperone TRAP1 to client proteins shapes bioenergetic and proteostatic adaptations of cells, but the panel of TRAP1 clients is only partially defined. Here we show that TRAP1 interacts with F-ATP synthase, the protein complex that provides most cellular ATP. TRAP1 competes with the peptidyl-prolyl cis-trans isomerase cyclophilin D (CyPD) for binding to the oligomycin sensitivity-conferring protein (OSCP) subunit of F-ATP synthase, increasing its catalytic activity and counteracting the inhibitory effect of CyPD. Electrophysiological measurements indicate that TRAP1 directly inhibits a channel activity of purified F-ATP synthase endowed with the features of the permeability transition pore (PTP) and that it reverses PTP induction by CyPD, antagonizing PTP-dependent mitochondrial depolarization and cell death. Conversely, CyPD outcompetes the TRAP1 inhibitory effect on the channel. Our data identify TRAP1 as an F-ATP synthase regulator that can influence cell bioenergetics and survival and can be targeted in pathological conditions where these processes are dysregulated, such as cancer.

In recent years, 3D printing gained considerable attention in the orthopedic sector. This work evaluates the feasibility of producing orthopedic scoliosis braces by 3D printing, comparing performance and costs with classical thermoforming procedures. Critical parameters, such as manufacture time, mechanical properties, weight, and comfort are carefully considered. Polyethylene terephthalate glycol-modified (PETG) was selected among the several filaments materials present on the market. Printed samples were analyzed with electronic microscope, tensile, and impact tests and compared with thermoformed polyethylene (PE) and polypropylene (PP) samples. Moreover, a cost analysis was carried out for the specific application. The thermoformed brace of a volunteer patient affected by scoliosis was reproduced using reverse-engineering techniques. The model was then printed as a single piece and postprocessed by an expert orthotist. Subsequently, the patient wore the brace in a pilot case to compare comfort and mechanical effectiveness. Results show that the 3D printing fabrication method is able to provide a valid alternative to the current fabrication methods, being also very competitive in terms of costs. The morphological analysis does not show critical defects in 3D printed samples, while the mechanical tests highlighted their anisotropy, with an overall brittleness of PETG samples in the direction orthogonal to the fibers. However, in terms of mechanical stresses, a back brace should never reach the polymer yield stress, otherwise the shape would be modified and the therapeutic effect could be compromised. Finally, the patient reported the perception of improved support and no significant comfort differences compared with the thermoformed brace.

Glycosylation, a prevalent post-translational modification, plays a pivotal role in regulating intricate cellular processes by covalently attaching glycans to macromolecules. Dysregulated glycosylation is linked to a spectrum of diseases, encompassing cancer, neurodegenerative disorders, congenital disorders, infections, and inflammation. This review delves into the intricate interplay between glycosylation and protein conformation, with a specific focus on the profound impact of N-glycans on the selection of distinct protein conformations characterized by distinct interactomes—namely, protein assemblies—under normal and pathological conditions across various diseases. We begin by examining the spike protein of the SARS virus, illustrating how N-glycans regulate the infectivity of pathogenic agents. Subsequently, we utilize the prion protein and the chaperone glucose-regulated protein 94 as examples, exploring instances where N-glycosylation transforms physiological protein structures into disease-associated forms. Unraveling these connections provides valuable insights into potential therapeutic avenues and a deeper comprehension of the molecular intricacies that underlie disease conditions. This exploration of glycosylation’s influence on protein conformation effectively bridges the gap between the glycome and disease, offering a comprehensive perspective on the therapeutic implications of targeting conformational mutants and their pathologic assemblies in various diseases. The goal is to unravel the nuances of these post-translational modifications, shedding light on how they contribute to the intricate interplay between protein conformation, assembly, and disease.

The use of 3D digitizing tools is becoming the base for subject-specific products, such as the orthopaedic production process of orthoses and prostheses. This paper aims at comparing the metrological behaviour of low-cost devices (Kinect 1 and 2 by Microsoft, Structure Sensor by Occipital) and high-resolution active sensors (O&P Scan by Rodin4D, NextEngine Ultra HD, Konica Minolta Vivid 9i, GOM ATOS II 400 and Artec Leo) for the survey of human body parts. A calibrated flat plane and a test-field composed of eight calibrated spheres of different radii and placed at different heights were used to evaluate the standard quality parameters (flatness, probing errors in form and size and the standard deviation) for each device as recommended by the VDI/VDE 2634 guidelines. Subsequently, three different parts of a mannequin were surveyed as samples of human body parts. The results demonstrated the higher accuracy of fixed devices with respect to handheld ones, among which Artec Leo and Structure Sensor provided a satisfying level of accuracy for the orthopaedic application. Moreover, the handheld devices enabled performing a fast reconstruction of the mannequin parts in about 20 s, which is acceptable for a person that has to remain as still as possible. For this reason, the Structure Sensor was further tested with five motion approaches which identified that smooth motion provides the lowest deviation and higher reliability. The work demonstrated the appropriateness of handheld devices for the orthopaedic application requirements in terms of speed, accuracy and costs.