CryoEM structure and small-angle X-ray scattering analyses of porcine retinol-binding protein 3.

The vertebrate visual cycle hinges on enzymatically converting all--retinol (at-ROL) into 11--retinal (11c-RAL), the chromophore that binds to opsins in photoreceptors, forming light-responsive pigments. When struck by a photon, these pigments activate the phototransduction pathway and initiate the process of vision. The enzymatic isomerization of at-ROL, crucial for restoring the visual pigments and preparing them to receive new light stimuli, relies on various enzymes found in both the photoreceptors and retinal pigment epithelium cells.

Towards a New Biomarker for Diabetic Retinopathy: Exploring RBP3 Structure and Retinoids Binding for Functional Imaging of Eyes In Vivo.

Diabetic retinopathy (DR) is a severe disease with a growing number of afflicted patients, which places a heavy burden on society, both socially and financially. While there are treatments available, they are not always effective and are usually administered when the disease is already at a developed stage with visible clinical manifestation. However, homeostasis at a molecular level is disrupted before visible signs of the disease are evident.

Insights into the Distribution and Functional Properties of l-Asparaginase in the Archaeal Domain and Characterization of Asparaginase Belonging to the Novel Family Asp2like1.

l-Asparaginase catalyzes the hydrolysis of l-asparagine to aspartic acid and ammonia and is used in the medical and food industries. In this investigation, from the proteomes of 176 archaeal organisms (with completely sequenced genomes), 116 homologs of l-asparaginase were obtained from 86 archaeal organisms segregated into Asp1, Asp2, IaaA, Asp2like1, and Asp2like2 families based on the conserved domain. The similarities and differences in the structure of selected representatives from each family are discussed.

Characterization of Cyclophilin from Thaumarchaeota Implications on the Diversity of Chaperone-like Activity in the Archaeal Domain.

The Archaea constitute separate domain of life and show resemblance with bacteria in their metabolic pathways while showing similarity with eukaryotes at the level of molecular processes such as cell division, DNA replication, protein synthesis, and proteostasis. However, the molecular machinery of archaea can be considered a simpler version of that found in eukaryotes because of the absence of multiple paralogs for any given molecular factor. Therefore, archaeal systems can possibly be used as a model system for understanding the eukaryotic protein folding machinery and thereby may help to address the molecular mechanism of various protein (mis)foldings and diseases.

Distribution of Peptidyl-Prolyl Isomerase (PPIase) in the Archaea.

Cis-trans isomerization of the peptide bond prior to proline is an intrinsically slow process but plays an essential role in protein folding. isomerization reaction is catalyzed by Peptidyl-prolyl isomerase (PPIases), a category of proteins widely distributed among all the three domains of life. The present study is majorly focused on the distribution of different types of PPIases in the archaeal domain.

Biophysical and biochemical characterization of a thermostable archaeal cyclophilin from Methanobrevibacter ruminantium.

The archaeal protein folding machinery is quite similar to that found in eukaryotes, especially in terms of shared components like chaperones. Cyclophilins are chaperones found in both eukaryotes and archaea, which catalyze the reversible cis-trans isomerization around peptidyl-prolyl imide bond (PPIase activity). Eukaryotes possess multiple cyclophilin genes, many of which have acquired divergent functions.

Functional divergence and comparative in-silico study of Cas4 proteins of DUF83 class.

Clustered Regularly Interspaced Short Palindromic Repeats-CRISPR associated (CRISPR-Cas) systems present in genomes of bacteria and archaea have been the focus of many research studies recently. The Cas4 proteins of these systems are thought to be responsible for the adaptation step in the CRISPR mechanism. Cas4 proteins exhibit low sequence similarity among themselves and are currently classified into 2 main classes: DUF83 and DUF911.