Biology subjects

Pey, A. L.

Publications and source records attributed to Pey, A. L..

4 recordsLinked to original sources

bioRxiv2024

Engineered Oxalate decarboxylase boosts activity and stability for biological applications

Oxalate decarboxylase (OxDC) from Bacillus subtilis is a Mn-dependent hexameric enzyme which converts oxalate to carbon dioxide and formate. Recently, OxDC has attracted the interest of the scientific community, due to its biotechnological and medical applications for the treatment of hyperoxalurias, a group of pathologic conditions associated with excessive oxalate urinary excretion due to either increased endogenous production or increased exogenous absorption. The fact that OxDC displays optimum pH in the acidic range, represents a big limitation for most biotechnological applications involving processes occurring at neutral pH, where the activity and stability of the enzyme are remarkably reduced. Here, through bioinformatics-guided protein engineering, followed by combinatorial mutagenesis and analyses of activity and thermodynamic stability, we identified a double mutant of OxDC endowed with enhanced catalytic efficiency and stability under physiological conditions. The obtained engineered form of OxDC offers a potential tool for improved intestinal oxalate degradation in hyperoxaluria patients.

biochemistry↗

bioRxiv2024

Minimized Sample Consumption for Time-Resolved Serial Crystallography Applied to the Redox Cycle of Human NQO1

Sample consumption for serial femtosecond crystallography (SFX) with X-ray free electron lasers (XFELs) remains a major limitation preventing broader use of this powerful technology in macromolecular crystallography. This drawback is exacerbated in the case of time-resolved (TR)-SFX experiments, where the amount of sample required per reaction time point is multiplied by the number of time points investigated. Thus, in order to reduce the limitation of sample consumption, here we demonstrate the implementation of segmented droplet generation in conjunction with a mix-and-inject approach for TR studies on NAD(P)H:quinone oxidoreductase 1 (NQO1). We present the design and application of mix-and-inject segmented droplet injectors for the Single Particles, Clusters, and Biomolecules & Serial Femtosecond Crystallography (SPB/SFX) instrument at the European XFEL (EuXFEL) with a synchronized droplet injection approach that allows liquid phase protein crystal injection. We carried out TR-crystallography experiments with this approach for a 305 ms and a 1190 ms time point in the reaction of NQO1 with its coenzyme NADH. With this successful TR-SFX approach, up to 97% of the sample has been conserved compared to continuous crystal suspension injection with a gas dynamic virtual nozzle. Furthermore, the obtained structural information for the reaction of NQO1 with NADH is an important part of the future elucidation of the reaction mechanism of this crucial therapeutic enzyme.

biochemistry↗

bioRxiv2023

Structural dynamics and functional cooperativity of human NQO1 by ambient temperature serial crystallography and simulations

The human NQO1 (hNQO1) is a FAD-dependent oxidoreductase that catalyzes the two-electron reduction of quinones to hydroquinones, being essential for the antioxidant defense system, stabilization of tumor suppressors, and activation of quinone-based chemotherapeutics, and it is over-expressed in several tumors, which makes it an attractive cancer drug target. To decipher new structural insights into the flavin reductive half-reaction of the catalytic mechanism of hNQO1, we have carried serial crystallography experiments at new ID29 beamline of the ESRF to determine, to the best of our knowledge, the first structure of the hNQO1 in complex with NADH. The use of room temperature serial crystallography with microcrystals has been key to study this mechanism. We have also performed molecular dynamics simulations of free hNQO1 and in complex with NADH. Both structural results and MD simulations have supported that the binding of NADH significantly decreases protein dynamics and stabilizes hNQO1 especially at the dimer core and interface. This is the first structural evidence that the hNQO1 functional cooperativity is driven by structural communication between the active sites through long-range propagation of cooperative effects across the hNQO1 structure. Altogether, these results pave the way for future time-resolved studies, both at XFELs and synchrotrons, of the dynamics of hNQO1 upon binding to NADH as well as during the FAD cofactor reductive half-reaction. This knowledge will allow us to reveal unprecedented structural information of the relevance of the dynamics during the catalytic function of hNQO1.

biochemistry↗

bioRxiv2022

Effect of naturally-occurring mutations on the stability and function of cancer-associated NQO1: comparison of experiments and computation.

Recent advances in DNA sequencing technologies are revealing a large variability in the human genome. Our capacity to establish genotype-phenotype correlations in such large-scale is, however, limited. This task is particularly challenging due to the multifunctional nature of proteins. Here we describe an extensive analysis of the stability and function of naturally-occurring variants (found in the COSMIC and gnomAD databases) of the cancer-associated human NAD(P)H: quinone oxidoreductase 1 (NQO1). First, we performed in silico saturation mutagenesis studies (>5000 substitutions) aimed to identify regions in NQO1 important for stability and function. We then experimentally characterized twenty-two naturally-occurring variants in terms of protein levels during bacterial expression, solubility, thermal stability and coenzyme binding. These studies showed a good overall correlation between experimental analysis and computational predictions; also the magnitude of the effects of the substitutions are similarly distributed in variants from the COSMIC and gnomAD databases. Outliers in these experimental-computational genotype-phenotype correlations remain, and we discuss these on the grounds and limitations of our approaches. Our work represents a further step to characterize the mutational landscape of NQO1 in the human genome and may help to improve high-throughput in silico tools for genotype-phenotype correlations in multifunctional proteins associated with disease.

biophysics↗