OCTN1: A Widely Studied but Still Enigmatic Organic Cation Transporter Linked to Human Pathology and Drug Interactions

The Novel Organic Cation Transporter, OCTN1, is the first member of the OCTN subfamily; it belongs to the wider Solute Carrier family SLC22, which counts many members including cation and anion organic transporters. The tertiary structure has not been resolved for any cation organic transporter. The functional role of OCNT1 is still not well assessed despite the many functional studies so far conducted. The lack of a definitive identification of OCTN1 function can be attributed to the different experimental systems and methodologies adopted for studying each of the proposed ligands. Apart from the contradictory data, the international scientific community agrees on a role of OCTN1 in protecting cells and tissues from oxidative and/or inflammatory damage. Moreover, the involvement of this transporter in drug interactions and delivery has been well clarified, even though the exact profile of the transported/interacting molecules is still somehow confusing. Therefore, OCTN1 continues to be a hot topic in terms of its functional role and structure. This review focuses on the most recent advances on OCTN1 in terms of functional aspects, physiological roles, substrate specificity, drug interactions, tissue expression, and relationships with pathology.

Identification and Evolutionary Characteristic Analysis of STARD Gene Family, and Overexpression VvSTARD5 Responses to Salt Stress in Tomato

This study aimed to have a full understanding of the steroidogenic acute regulatory gene family member and evolutionary relationship in grape. 23 VvSTARD gene members were identified and divided into five groups in different species. Analyses of the gene codon preference, selective pressure, and tandem duplication of the VvSTARD, AtSTARD, and OsSTARD genes indicated that synteny relationship occurred in grapes, Arabidopsis thaliana, and rice genomes. The 8 lipid transporter proteins were found in the tertiary structure of the STARD gene family in grape. Expression profiles of the three species microarrays showed that the expression levels of the STARD genes in different organs and the response to abiotic stress in the same subgroup had similar characteristics. In addition, analysis of the VvSTARD genes expression levels was detected in response to different hormones and abiotic stresses by quantitative real-time polymerase chain reaction (qRT-PCR), and the results were the same as those predicted by the cis-elements and the expression profiles. Meanwhile, VvSTARD5 gene was screened in high concentration NaCl treatment by qRT-PCR. Furthermore, the VvSTARD5 was located at the nucleus by subcellular location. Through the function analysis of salt tolerance in transgenic tomato, overexpression VvSTARD5 obviously improved tolerance to salt stress. Taken together, our findings Preliminary identify the functions of VvSTARD gene family and vertify STARD5 that be likely involved in regulating salt tolerance, which may have potential application molecular breeding in grape.

Circular Dichroism Spectral Similarity Plots to Extend Validation and Correction to All Measured Wavelengths

Interlaboratory comparisons of circular dichroism (CD) spectra are useful for developing confidence in the measurements associated with optically active molecules. These measurements also help define the higher-order (secondary and tertiary) structure of biopolymers. Unfortunately, the extent of the validity of these measurements has been unclear. In this work, a method is described to extend CD validation over the entire observed wavelength range using what will be called spectral similarity plots. The method involves plotting, wavelength by wavelength, all measured spectral intensities of a sample at one concentration against the intensity values of the same material at a different concentration or pathlength. These spectral similarity plots validate the instrument in terms of spectral shape and whether the shape is shifted in intensity and/or in wavelength. This comparison tests the linearity of instrument’s signal, the balance of its left and right polarizations, its wavelengths, and its spectral intensity scales. When the process is applied to materials with accepted and archived intensity values, the method can be linked to older single-wavelength and double-wavelength calibration techniques. Further, spectral similarity testing of CD spectra from samples with different concentrations run in different labs suggests that improved interlaboratory validation of CD data is possible. Since a database of archival CD measurements is available online, spectral similarity comparisons could possibly provide the ability to compare linearity, polarization balance, wavelength, and spectral intensity between all current CD instruments. If the preliminary results published here prove robust and transferable, then comparisons of full-wavelength range spectra to archived data using spectral similarity plots should become part of the standard process to validate and calibrate the performance of CD instruments.

A Novel Virus Discovered in the Yeast Pichia membranifaciens.

Mycoviruses are widely distributed across fungi, including yeasts of the Saccharomycotina subphylum. It was recently discovered that the yeast species Pichia membranifaciens contained double stranded RNAs (dsRNAs) that were predicted to be of viral origin. The fully sequenced dsRNA is 4,578 bp in length, with RNA secondary structures similar to the packaging, replication, and frameshift signals of totiviruses of the family Totiviridae. This novel virus has been named Pichia membranifaciens virus L-A (PmV-L-A) and is related to other totiviruses previously described within the Saccharomycotina yeasts. PmV-L-A is part of a monophyletic subgroup within the I-A totiviruses, implying a common ancestry between mycoviruses isolated from the Pichiaceae and Saccharomycetaceae yeasts. Energy minimized AlphaFold2 molecular models of the PmV-L-A Gag protein revealed structural conservation with the previously solved structure of the Saccharomyces cerevisiae virus L-A (ScV-L-A) Gag protein. The predicted tertiary structure of the PmV-L-A Pol and its homologs provide details of the potential mechanism of totivirus RNA-dependent RNA polymerases (RdRps) because of structural similarities to the RdRps of mammalian dsRNA viruses. Insights into the structure, function, and evolution of totiviruses gained from yeasts is important because of their parallels with mammalian viruses and the emerging role of totiviruses in animal disease.

T-hairpin structure found in the RNA element involved in piRNA biogenesis

PIWI-interacting RNAs (piRNAs) repress transposons to protect the germline genome from DNA damage caused by transposon transposition. In Drosophila, the Traffic jam (Tj) mRNA is consumed to produce piRNA in its 3′ UTR. A cis element located within the 3′-UTR, Tj-cis, is necessary for piRNA biogenesis. In this study, we analyzed the structure of the Tj-cis RNA, a 100 nt RNA corresponding to the Tj-cis element, by the SHAPE and NMR analyses and found that a stable hairpin structure formed in the 5′ half of the Tj-cis RNA. The tertiary structure of the 16 nt stable hairpin was analyzed by NMR, and a novel stem-loop structure, the T-hairpin, was found. In the T-hairpin, four uridine residues are exposed to the solvent, suggesting that this stem loop is the target of Yb protein, a Tudor domain-containing piRNA biogenesis factor. The piRNA biogenesis assay showed that both the T-hairpin and the 3′ half are required for the function of the Tj-cis element, suggesting that both the T-hairpin and the 3′ half are recognized by Yb protein.

Prediction of the RNA Tertiary Structure Based on a Random Sampling Strategy and Parallel Mechanism

Background: Macromolecule structure prediction remains a fundamental challenge of bioinformatics. Over the past several decades, the Rosetta framework has provided solutions to diverse challenges in computational biology. However, it is challenging to model RNA tertiary structures effectively when the de novo modeling of RNA involves solving a well-defined small puzzle.Methods: In this study, we introduce a stepwise Monte Carlo parallelization (SMCP) algorithm for RNA tertiary structure prediction. Millions of conformations were randomly searched using the Monte Carlo algorithm and stepwise ansatz hypothesis, and SMCP uses a parallel mechanism for efficient sampling. Moreover, to achieve better prediction accuracy and completeness, we judged and processed the modeling results.Results: A benchmark of nine single-stranded RNA loops drawn from riboswitches establishes the general ability of the algorithm to model RNA with high accuracy and integrity, including six motifs that cannot be solved by knowledge mining–based modeling algorithms. Experimental results show that the modeling accuracy of the SMCP algorithm is up to 0.14 Å, and the modeling integrity on this benchmark is extremely high.Conclusion: SMCP is an ab initio modeling algorithm that substantially outperforms previous algorithms in the Rosetta framework, especially in improving the accuracy and completeness of the model. It is expected that the work will provide new research ideas for macromolecular structure prediction in the future. In addition, this work will provide theoretical basis for the development of the biomedical field.

IN SILICO CHARACTERIZATION OF HUMAN INTERFERON ALPHA/BETA RECEPTOR 2 (ISOFORM A, B AND C) PROTEIN

Objective: To predict the tertiary structure of human interferon alpha/beta receptor 2 protein. Study Design: Structure prediction by using bio informatics tools. Place and Duration of Study: Department of Biochemistry, Swat Medical College (STMC), Saidu Shareef, Swat, Pakistan, from Aug 2019 to Dec 2019. Methodology: All protein sequences of human interferon alpha/beta receptor 2 (isoforma, b and c) (IFNAR-2) were retrieved through the BLAST search (The Basic Local Alignment Search Tool) from available databases ‘NCBI’ (National Centre for Biotechnology Information) and ‘Uni Prot KB’ (The Universal Protein Resource). Sequence alignment was conducted by using Clustal Omega, to get the consensus sequence for IFNAR-2 protein. Consensus protein sequence of human IFNAR-2 was used for the prediction of the three-dimensional structure by employing Swiss-Model Server. Moreover, subcellular localization analysis was also performed by using CELLO2GO program. Results: Structural model of human IFNAR-2 protein was predicted and evaluated by Ramachandran dimension. Cellular localization of tertiary topological domains of the predicted models were revealed probability of localization of IFNAR-2 protein (isoform a, b & c) is highest in the plasma membrane due to the presence of the transmembrane alpha helical regions. Conclusion: This study predicted the tertiary structural dimensions of human IFNAR-2 protein, including the specific topological domains that contribute towards the subcellular compartmentalization and functional characteristics.

Effects of High-Intensity Ultrasound Pretreatment on Structure, Properties, and Enzymolysis of Walnut Protein Isolate

The purpose of this paper was to investigate the effect of high-intensity ultrasonication (HIU) pretreatment before enzymolysis on structural conformations of walnut protein isolate (WPI) and antioxidant activity of its hydrolysates. Aqueous WPI suspensions were subjected to ultrasonic processing at different power levels (600–2000 W) and times (5–30 min), and then changes in the particle size, zeta (ζ) potential, and structure of WPI were investigated, and antioxidant activity of its hydrolysates was determined. The particle size of the particles of aqueous WPI suspensions was decreased after ultrasound, indicating that sonication destroyed protein aggregates. The ζ-potential values of a protein solution significantly changed after sonication, demonstrating that the original dense structure of the protein was destroyed. Fourier transform infrared spectroscopy indicated a change in the secondary structure of WPI after sonication, with a decrease in β-turn and an increase in α-helix, β-sheet, and random coil content. Two absorption peaks of WPI were generated, and the fluorescence emission intensity of the proteins decreased after ultrasonic treatment, indicating that the changes in protein tertiary structure occurred. Moreover, the degree of hydrolysis and the antioxidant activity of the WPI hydrolysates increased after sonication. These results suggest that HIU pretreatment is a potential tool for improving the functional properties of walnut proteins.