Structural analysis of dUTPase from Helicobacter pylori reveals unusual activity for dATP.

Helicobacter pylori deoxyuridine triphosphate nucleotidohydrolase (HpdUTPase) is a key enzyme in the synthesis of the thymidine nucleotide pathway. It catalyzes the hydrolysis of dUTP to dUMP and releases pyrophosphate. This enzyme has been shown to be essential in several pathogenic organisms.

The 26 S proteasome in Entamoeba histolytica: divergence of the substrate binding pockets from host proteasomes.

Objective: Proteasomes are conserved proteases crucial for proteostasis in eukaryotes and are promising drug targets for protozoan parasites. Yet, the proteasomes of Entamoeba histolytica remain understudied. The study's objective was to analyse the differences in the substrate binding pockets of amoeba proteasomes from those of host, and computational modelling of β5 catalytic subunit, with the goal of finding selective inhibitors.

Identification of Small Molecule Inhibitors Targeting Phosphoserine Phosphatase: A Novel Target for the Development of Antiamoebic Drugs.

Amoebiasis, a widespread disease caused by the protozoan parasite , poses challenges due to the adverse effects of existing antiamoebic drugs and rising drug resistance. Novel targeted drugs are in need of the hour to combat the prevalence of this disease. Given the significance of cysteine for survival, the rate-determining step in the serine (the sole substrate of cysteine synthesis) biosynthetic pathway, i.

Biophysical and functional characterization of N-terminal domain of Human Interferon Regulatory Factor 6.

Background: Interferon regulatory factor 6 (IRF6) has a key function in palate fusion during palatogenesis during embryonic development, and mutations in IRF6 cause orofacial clefting disorders.

Methods And Results: The in silico analysis of IRF6 is done to obtain leads for the domain boundaries and subsequently the sub-cloning of the N-terminal domain of IRF6 into the pGEX-2TK expression vector and successfully optimized the overexpression and purification of recombinant glutathione S-transferase-fused NTD-IRF6 protein under native conditions. After cleavage of the GST tag, NTD-IRF6 was subjected to protein folding studies employing Circular Dichroism and Intrinsic fluorescence spectroscopy at variable pH, temperature, and denaturant.

Small molecules that disrupt RAD54-BLM interaction hamper tumor proliferation in colon cancer chemoresistance models.

RAD54 and BLM helicase play pivotal roles during homologous recombination repair (HRR) to ensure genome maintenance. BLM amino acids (aa 181-212) interact with RAD54 and enhance its chromatin remodeling activity. Functionally, this interaction heightens HRR, leading to a decrease in residual DNA damage in colon cancer cells.

Identification of potential novel inhibitors against the SARS-CoV-2 spike protein: targeting RBD and ACE2 interaction.

The SARS-CoV-2, responsible for the COVID-19 pandemic has wrecked devastation throughout the globe. The SARS-CoV-2 spike (S) glycoprotein plays crucial role in virus attachment, fusion, and entry. This study aims to identify inhibitors targeting the receptor binding domain (RBD) of the S protein using computational and experimental techniques.

Machine learning-based modulation of Ca-binding affinity in EF-hand proteins and comparative structural insights into site-specific cooperative binding.

Ca-binding proteins are present in almost all living organisms and different types display different levels of binding affinities for the cation. Here, we report two new scoring schemes enabling the user to estimate and manipulate the calcium binding affinities in EF hand containing proteins. To validate this, we designed a unique EF-hand loop capable of binding calcium with high affinity by altering five residues.

Insight into the Conformational Transitions of Serine Acetyl Transferase Isoforms in : Implications for Structural and Functional Balance.

Serine acetyl transferase (SAT) is one of the crucial enzymes in the cysteine biosynthetic pathway and an essential enzyme for the survival of , the causative agent of amoebiasis. expresses three isoforms of SAT, where SAT1 and SAT2 are inhibited by the final product cysteine, while SAT3 is not inhibited. SAT3 has a slightly elongated C-terminus compared to SAT1.

Structural and functional studies of serine acetyltransferase isoform from Entamoeba histolytica reveals novel role of the C-terminal tail in loss of regulation from feedback inhibition.

Serine acetyltransferase (SAT) catalyzes the acetylation of l-serine in the first step of the two-step pathway to synthesize L-cysteine in bacteria, protozoans and plants. L-cysteine is known to be involved in feedback regulation of SAT. However, in E.

Unravelling the Biology of EhActo as the First Cofilin From .

Actin-depolymerising factors (ADF) are a known family of proteins that regulate actin dynamics. Actin regulation is critical for primitive eukaryotes since it drives their key cellular processes. , a protist human pathogen harbours eleven proteins within this family, however, with no actin depolymerising protein reported to date.

Cdc42/Rac Interactive Binding Containing Effector Proteins in Unicellular Protozoans With Reference to Human Host: Locks of the Rho Signaling.

Small GTPases are the key to actin cytoskeleton signaling, which opens the lock of effector proteins to forward the signal downstream in several cellular pathways. Actin cytoskeleton assembly is associated with cell polarity, adhesion, movement and other functions in eukaryotic cells. Rho proteins, specifically Cdc42 and Rac, are the primary regulators of actin cytoskeleton dynamics in higher and lower eukaryotes.

A unique aromatic cluster near the active site of H. pylori CPA is essential for catalytic function.

Polyamines are essential for cell growth and proliferation. In plants and many bacteria, including Helicobacter pylori, the parent polyamine putrescine is only produced through the metabolism of N-carbamoylputrescine by N-carbamoylputrescine amidase (CPA). Thus, CPA is a crucial intermediate enzyme.

Functional implications of residues of the B' motif of geminivirus replication initiator protein in its helicase activity.

Geminivirus replication initiator protein (Rep) is a multifunctional viral protein required for replication. During the process of viral replication, Rep acts as a site- and strand-specific endonuclease, ligase, ATPase, and helicase. B' motif and β-hairpin loop of the geminivirus Rep are conserved and important for Rep-mediated helicase activity required for viral replication.

Redox homeostasis in Mycobacterium tuberculosis is modulated by a novel actinomycete-specific transcription factor.

Mycobacterium tuberculosis (Mtb) has evolved diverse cellular processes in response to the multiple stresses it encounters within the infected host. We explored available TnSeq datasets to identify transcription factors (TFs) that are essential for Mtb survival inside the host. The analysis identified a single TF, Rv1332 (AosR), conserved across actinomycetes with a so-far uncharacterized function.

Inhibiting Pyridoxal Kinase of Is Lethal for This Pathogen.

Pyridoxal 5'-phosphate (PLP) functions as a cofactor for hundreds of different enzymes that are crucial to the survival of microorganisms. PLP-dependent enzymes have been extensively characterized and proposed as drug targets in . This pathogen is unable to synthesize vitamin B pathway and relies on the uptake of vitamin B vitamers from the host which are then phosphorylated by the enzyme pyridoxal kinase to produce PLP, the active form of vitamin B.

Structure-based inhibitor screening of natural products against NSP15 of SARS-CoV-2 revealed thymopentin and oleuropein as potent inhibitors.

Unlabelled: Coronaviruses are enveloped, non-segmented positive-sense RNA viruses with the largest genome among RNA viruses. Their genome contains a large replicase ORF which encodes nonstructural proteins (NSPs), structural, and accessory genes. NSP15 is a nidoviral RNA uridylate-specific endoribonuclease (NendoU) with C-terminal catalytic domain.

Structural analysis of EhPSP in complex with 3-phosphoglyceric acid from Entamoeba histolytica reveals a basis for its lack of phosphoglycerate mutase activity.

Entamoeba histolytica phosphoserine phosphatase (EhPSP), a regulatory enzyme in the serine biosynthetic pathway, is also a structural homolog of cofactor-dependent phosphoglycerate mutase (dPGM). However, despite sharing many of its catalytic residues with dPGM, EhPSP displays no significant mutase activity. In the current work, we determined a crystal structure of EhPSP in complex with 3-PGA to 2.

Phosphoserine Aminotransferase has Conserved Active Site from Microbes to Higher Eukaryotes with Minor Deviations.

Serine is ubiquitously synthesized in all living organisms from the glycolysis intermediate 3-phosphoglycerate (PGA) by phosphoserine biosynthetic pathway, consisting of three different enzymes, namely: 3-phosphoglycerate dehydrogenase (PGDH), phosphoserine aminotransferase (PSAT), and phosphoserine phosphatase (PSP). Any functional defect or mutation in these enzymes may cause deliberating conditions, such as colon cancer progression and chemoresistance in humans. Phosphoserine aminotransferase (PSAT) is the second enzyme in this pathway that converts phosphohydroxypyruvate (PHP) to O-phospho-L-serine (OPLS).

An evolutionary non-conserved motif in Helicobacter pylori arginase mediates positioning of the loop containing the catalytic residue for catalysis.

The binuclear metalloenzyme Helicobacter pylori arginase is important for pathogenesis of the bacterium in the human stomach. Despite conservation of the catalytic residues, this single Trp enzyme has an insertion sequence (-153ESEEKAWQKLCSL165-) that is extremely crucial to function. This sequence contains the critical residues, which are conserved in the homolog of other Helicobacter gastric pathogens.

Nuclear receptor SHP dampens transcription function and abrogates mitotic chromatin association of PXR and ERα via intermolecular interactions.

Mitosis is a cellular process that produces two identical progenies. Genome-wide transcription is believed to be silenced during mitosis. However, some transcription factors have been reported to associate with the mitotic chromatin to uphold a role in 'gene-bookmarking'.

Uncovering the Cyclic AMP Signaling Pathway of the Protozoan Parasite and Understanding Its Role in Phagocytosis.

Second messenger signaling controls a surprisingly diverse range of processes in several eukaryotic pathogens. Molecular machinery and pathways involving these messengers thus hold tremendous opportunities for therapeutic interventions. Relative to Ca signaling, the knowledge of a crucial second messenger cyclic AMP (cAMP) and its signaling pathway is very scant in the intestinal parasite .