Biochimica et biophysica acta. Proteins and proteomics最新文献

Long interspersed nuclear elements-1 (LINEs-1) are known to be active human retrotransposons containing two protein-coding genes, ORF1 and ORF2, whose expression results in the production of two proteins-ORF1p-L1 and ORF2p-L1, respectively. Activation of LINE-1 may occur during the early stages of lung, prostate, esophageal, colon or breast cancer progression, often without obvious pathological symptoms or any overt signs of disease. In this study, we developed a method for preparing the LINE-1 proteins ORF1p-L1 and the reverse transcriptase (RT) domain of ORF2p-L1 and demonstrated their potential application as antigens in gastric cancer diagnostics. Both antigens were expressed as insoluble inclusion bodies in a bacterial expression system (E. coli BL21 (DE3) pLysS) using laboratory-scale fermentation. The preparation protocol involved solubilizing the inclusion bodies with a chaotropic agent, followed by multiple protein purification steps and subsequent renaturation of the proteins by dialysis under acidic conditions. At decreasing concentrations of the chaotropic agent, ORF1p-L1 and the RT domain of ORF2p-L1 were found to weakly bind to cation-exchange resins or to aggregate, whereas irreversible protein binding occurred under acidic conditions. The biological activity of the refolded ORF1p-L1 was confirmed by assessing its hybridization activity, while the reverse transcriptase activity of the RT domain of ORF2p-L1 was also successfully confirmed. Both refolded proteins reveal antigen-antibody response against antibodies in serum samples of patients with gastric cancer.

Impaired function of the anterior cingulate cortex (ACC) is widely recognized as a critical factor in drug dependence. This study aimed to investigate protein alterations in the ACC of morphine-dependent mice using 4D label-free quantitative proteomics. Procrustes analysis and Pearson correlation analysis on the differentially expressed proteins (DEPs) and the phenotypes of morphine dependence identified 81 DEPs (p-value <0.05). Advanced bioinformatics analysis of these DEPs suggested dysregulation of several biological pathways in the ACC of morphine-dependent mice, including mitochondrial energy metabolism, endoplasmic reticulum-to-nucleus signaling, inhibitory synapse assembly, and intracellular trafficking, secretion, and vesicle-mediated transport. These findings provide a basis for understanding the proteomic alterations and offer an integrated perspective on the biomolecular changes in the ACC associated with morphine dependence.

Leishmania (Viannia) braziliensis Thor strain contains subpopulations Thor03, Thor10, and Thor22 with distinct biological and infection profiles in vitro and vivo. This study investigated GPI-anchored metalloproteases from the Thor strain and its subpopulations using phospholipase C treatment followed by Zn²⁺-charged affinity chromatography. An electrochemical biosensor based on screen-printed carbon electrodes and differential pulse voltammetry was used to detect metalloprotease activity and responsiveness to the ortho-phenanthroline inhibitor. Promastigotes and axenic amastigotes metalloproteases exhibit different binding profiles to the ortho-phenanthroline inhibitor which led to specific discrimination of these analytes. The highest sensitivity was observed in proteases from Thor10 promastigotes and Thor axenic amastigotes, with detection limits of 5 μM and 1 μM, respectively. The detectable concentration range for these analytes varied among subpopulations: for promastigotes, from 1000 μM down to 5 μM (with Thor10 showing the broadest range), and for axenic amastigotes, from 1000 μM down to 1 μM (with Thor and Thor10 exhibiting the greatest sensitivity). These differences suggest a variable abundance of metalloproteases among subpopulations. The findings underscore the biosensor's potential as a sensitive, specific tool for real-time analysis of Leishmania enzymes, offering a novel, systematic approach for studying enzyme function and virulence in parasite phenotypes.