Identification of Schistosoma haematobium and Schistosoma mansoni linear B-cell epitopes with diagnostic potential using in silico immunoinformatic tools and peptide microarray technology.

Introduction: Immunoinformatic tools can be used to predict schistosome-specific B-cell epitopes with little sequence identity to human proteins and antigens other than the target. This study reports an approach for identifying schistosome peptides mimicking linear B-cell epitopes using in-silico tools and peptide microarray immunoassay validation.

Method: Firstly, a comprehensive literature search was conducted to obtain published schistosome-specific peptides and recombinant proteins with the best overall diagnostic performances.

The discovery of hidden guanylate cyclases (GCs) in the proteome.

Recent discoveries have established functional guanylate cyclase (GC) catalytic centers with low activity within kinase domains in plants. These crypto GCs generate guanosine 3',5'-cyclic monophosphate (cGMP) essential for both intramolecular and downstream signaling. Here, we have set out to search for such crypto GCs moonlighting in kinases in the proteome and identified 18 candidates, including the neurotropic receptor tyrosine kinase 1 (NTRK1).

Peptide microarray analysis of in-silico predicted B-cell epitopes in SARS-CoV-2 sero-positive healthcare workers in Bulawayo, Zimbabwe.

Immunogenic peptides that mimic linear B-cell epitopes coupled with immunoassay validation may improve serological tests for emerging diseases. This study reports a general approach for profiling linear B-cell epitopes derived from SARS-CoV-2 using an in-silico method and peptide microarray immunoassay, using healthcare workers' SARS-CoV-2 sero-positive sera. SARS-CoV-2 was tested using rapid chromatographic immunoassays and real-time reverse-transcriptase polymerase chain reaction.

Host cell stress response as a predictor of COVID-19 infectivity and disease progression.

The coronavirus disease (COVID-19) caused by a coronavirus identified in December 2019 has caused a global pandemic. COVID-19 was declared a pandemic in March 2020 and has led to more than 6.3 million deaths.

(De)Activation (Ir)Reversibly or Degradation: Dynamics of Post-Translational Protein Modifications in Plants.

The increasing dynamic functions of post-translational modifications (PTMs) within protein molecules present outstanding challenges for plant biology even at this present day. Protein PTMs are among the first and fastest plant responses to changes in the environment, indicating that the mechanisms and dynamics of PTMs are an essential area of plant biology. Besides being key players in signaling, PTMs play vital roles in gene expression, gene, and protein localization, protein stability and interactions, as well as enzyme kinetics.

Functional Roles of RNA-Binding Proteins in Plant Signaling.

RNA-binding proteins (RBPs) are typical proteins that bind RNA through single or multiple RNA-binding domains (RBDs). These proteins have a functional role in determining the fate or function of the bound RNAs. A few hundred RBPs were known through in silico prediction based on computational assignment informed by structural similarity and the presence of classical RBDs.

Phosphorylation of the dimeric cytoplasmic domain of the phytosulfokine receptor, PSKR1.

Phytosulfokines (PSKs) are plant peptide hormones that co-regulate plant growth, differentiation and defense responses. PSKs signal through a plasma membrane localized leucine-rich repeat receptor-like kinase (phytosulfokine receptor 1, PSKR1) that also contains a functional cytosolic guanylate cyclase with its cyclase catalytic center embedded within the kinase domain. To functionally characterize this novel type of overlapping dual catalytic function, we investigated the phosphorylation of PSKR1 in vitro Tandem mass spectrometry of the cytoplasmic domain of PSKR1 (PSKR1cd) revealed at least 11 phosphorylation sites (8 serines, 2 threonines and 1 tyrosine) within the PSKR1cd.

Comparison of moonlighting guanylate cyclases: roles in signal direction?

Over 30 receptor-like kinases contain a guanylate cyclase (GC) catalytic centre embedded within the C-terminal region of their kinase domain in the model plant Arabidopsis. A number of the kinase GCs contain both functional kinase and GC activity in vitro and the natural ligands of these receptors stimulate increases in cGMP within isolated protoplasts. The GC activity could be described as a minor or moonlighting activity.

Calcium is the switch in the moonlighting dual function of the ligand-activated receptor kinase phytosulfokine receptor 1.

Background: A number of receptor kinases contain guanylate cyclase (GC) catalytic centres encapsulated in the cytosolic kinase domain. A prototypical example is the phytosulfokine receptor 1 (PSKR1) that is involved in regulating growth responses in plants. PSKR1 contains both kinase and GC activities however the underlying mechanisms regulating the dual functions have remained elusive.

Structural and functional characterization of receptor kinases with nucleotide cyclase activity.

There has been an increase in the identification and characterization of plant receptor kinases possessing nucleotide cyclase activity. This has necessitated the development of robust methodologies for the structural and functional characterization of this biologically important family of proteins. Here we outline some of the techniques that can be effectively used in the characterization of this bifunctional family of proteins.

Solution structure of RING finger-like domain of retinoblastoma-binding protein-6 (RBBP6) suggests it functions as a U-box.

Retinoblastoma-binding protein-6 (RBBP6) plays a facilitating role, through its RING finger-like domain, in the ubiquitination of p53 by Hdm2 that is suggestive of E4-like activity. Although the presence of eight conserved cysteine residues makes it highly probable that the RING finger-like domain coordinates two zinc ions, analysis of the primary sequence suggests an alternative classification as a member of the U-box family, the members of which do not bind zinc ions. We show here that despite binding two zinc ions, the domain adopts a homodimeric structure highly similar to those of a number of U-boxes.

Modulation of Anopheles gambiae Epsilon glutathione transferase activity by plant natural products in vitro.

Elevated glutathione transferase (GST) E2 activity is associated with DDT resistance in the mosquito Anopheles gambiae. The search for chemomodulators that inhibit the function of AgGSTE2 would enhance the insecticidal activity of DDT. Therefore, we examined the interaction of novel natural plant products with heterologously expressed An.