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Biofilms are generally defined as communities of cells involved in a self-produced extracellular matrix adhered to a surface. In biofilms, the bacteria are less sensitive to host defense mechanisms and antimicrobial agents, due to multiple strategies, that involve modulation of gene expression, controlled metabolic rate, intercellular communication, composition, and 3D architecture of the extracellular matrix. These factors play a key role in streptococci pathogenesis, contributing to therapy failure and promoting persistent infections. The species of the pyogenic group together with Streptococcus pneumoniae are the major pathogens belonging the genus Streptococcus, and its biofilm growth has been investigated, but insights in the genetic origin of biofilm formation are limited. This review summarizes pyogenic streptococci biofilms with details on constitution, formation, and virulence factors associated with formation. publishersversion published

Human aldehyde oxidase (hAOX1) is a molybdenum enzyme with high toxicological importance, but its physiological role is still unknown. hAOX1 metabolizes different classes of xenobiotics and is one of the main drug-metabolizing enzymes in the liver, along with cytochrome P450. hAOX1 oxidizes and inactivates a large number of drug molecules and has been responsible for the failure of several phase I clinical trials. The interindividual variability of drug-metabolizing enzymes caused by single nucleotide polymorphisms (SNPs) is highly relevant in pharmaceutical treatments. In this study, we present the crystal structure of the inactive variant G1269R, revealing the first structure of a molybdenum cofactor (Moco)-free form of hAOX1. These data allowed to model, for the first time, the flexible Gate 1 that controls access to the active site. Furthermore, we inspected the thermostability of wild-type hAOX1 and hAOX1 with various SNPs (L438V, R1231H, G1269R or S1271L) by CD spectroscopy and ThermoFAD, revealing that amino acid exchanges close to the Moco site can impact protein stability up to 10 degrees C. These results correlated with biochemical and structural data and enhance our understanding of hAOX1 and the effect of SNPs in the gene encoding this enzyme in the human population. EnzymesAldehyde oxidase (); xanthine dehydrogenase (); xanthine oxidase (). DatabasesStructural data are available in the Protein Data Bank under the accession number .

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Aim: Glutathione S-transferase enzymes participates in detoxification of endogenous and exogenous electrophiles and in other cellular processes, such as electrophilic agents induced stress and growth factor-induced signaling, proliferation, differentiation, and apoptosis. This study is aimed to scrutinize the interaction of predominantly expressed GST isoforms (A1, A2, P1, M1, M2, M5 and T1) with two key partners of stress induced apoptotic pathway i.e. apoptosis signal-regulating kinase 1 (ASK1) and mitogen-activated protein kinase (MAPK8) using computational methods. Methods: The following computational workflow was implemented to predict the binding affinity of GST isoforms towards ASK1 and MAPK8. 1. Preparation of input sequence and structure dataset using UniProt and PDB databases. 2. Phylogenetic analysis of seven GST isoforms using Clustal Omega and MEGA to assess the evolutionary relationship. 3. String protein sequence search to construct the functional interactome for seven GSTs isoforms. 4. Preparation of the protein structures using MGL-ADT Tools. 5. Docking of GSTs with ASK1, MAPK8 using HADDOCK. 6. Prediction of hot spot regions of GSTs by in silico alanine scanning mutagenesis using DrugScorePPI. 7. Analysis of protein-protein docking results using PRODIGY, PDBSum and PyMOL. 8. Molecular dynamics simulation (MD) of GSTs with ASK1, MAPK8 using Gromacs. 9. Analysis and interpretation of MD results using PyMOL and GRACE. Results: Highest degree of homology was observed in two sub groups (SG) of GSTs. GSTA1, A2, P1 constituted SG1 and SG2 had GSTM1, M2 and M5. GSTT1 completely diverged from rest of the isoforms. GSTM family members exhibited higher binding affinity towards both MAPK8 as well as ASK1 followed by others.Whereas GSTP family also had higher binding affinity for ASK1 followed by others. Conclusion: GSTM family members exhibited higher binding affinity towards MAPK8 and ASK1 indicating their potential role in cellular processes other than metabolism.

Aldehyde oxidases (AOXs) are molybdo-flavoenzymes characterized by broad substrate specificity, oxidizing aromatic/aliphatic aldehydes into the corresponding carboxylic acids and hydroxylating various heteroaromatic rings. Mammals are characterized by a complement of species specific AOX isoenzymes, that varies from one in humans (AOX1) to four in rodents (AOX1, AOX2, AOX3 and AOX4). The physiological function of mammalian AOX isoenzymes is unknown, although human AOX1 is an emerging enzyme in phase-I drug metabolism. Indeed, the number of therapeutic molecules under development which act as AOX substrates is increasing. The recent crystallization and structure determination of human AOX1 as well as mouse AOX3 has brought new insights into the mechanisms underlying substrate/inhibitor binding as well as the catalytic activity of this class of enzymes.