Production of hepatitis C virus (HCV) core protein requires the cleavages of polyprotein by signal peptidase and signal peptide peptidase (SPP). Cleavage of signal peptide at the C-terminus of HCV core protein by SPP was characterized in this study. The spko mutant (mutate a.a. 189-193 from ASAYQ to PPFPF) is more efficient than the A/F mutant (mutate a.a 189 and 191 from A to F) in blocking the cleavage of signal peptide by signal peptidase. The cleavage efficiency of SPP is inversely proportional to the length of C-terminal extension of the signal peptide: the longer the extension, the less efficiency the cleavage is. Thus, reducing the length of C-terminal extension of signal peptide by signal peptidase cleavage could facilitate further cleavage by SPP. The recombinant core protein fused with signal peptide from the C-terminus of p7 protein, but not those from the C-termini of E1 and E2, could be cleaved by SPP. Therefore, the sequence of the signal peptide is important but not the sole determinant for its cleavage by SPP. Replacement of the HCV core protein E.R.-associated domain (a.a. 120-150) with the E.R.-associated domain (a.a.1-50) of SARS-CoV membrane protein results in the failure of cleavage of this recombinant protein by SPP, though this protein still is E.R.-associated. This result suggests that not only E.R.-association but also specific protein sequence is important for the HCV core protein signal peptide cleavage by SPP. Thus, our results suggest that both sequences of the signal peptide and the E.R.-associated domain are important for the signal peptide cleavage of HCV core protein by SPP.
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http://dx.doi.org/10.1007/s11373-006-9127-1 | DOI Listing |
Rev Cardiovasc Med
January 2025
Department of Cardiology, Gazi University Faculty of Medicine, 06560 Ankara, Turkey.
Background: Hypertension-mediated organ damage (HMOD) is a critical complication of hypertension that can present with cardiac, retinal, and renal manifestations and affect patient outcomes. Serum signal peptide, CUB (complement C1r/C1s, Uegf, and Bmp1) domain, and epidermal growth factor-like domain-containing protein 1 (SCUBE-1), a novel biomarker implicated in vascular pathology, shows promise for detecting HMOD. This study aims to explore the relation between SCUBE-1 levels and HMOD in hypertensive patients.
View Article and Find Full Text PDFAnal Chem
January 2025
Shanghai Key Laboratory of Functional Materials Chemistry, School of Chemistry and Molecular Engineering, East China University of Science and Technology, Meilong Road, Shanghai 200237, P. R. China.
Protein methylation has attracted increasing attention due to its significant regulatory roles in various biological processes. However, the diversity of methylation forms, subtle differences between methylated and nonmodified sites, and their ultralow abundances pose substantial challenges for capturing and isolating methylated peptides from biological samples. Herein, we develop a chromatographic method that utilizes 4-sulfonylcalix[4]arene (SC4A) as a mobile phase additive and Click-Maltose as the stationary phase to separate methylated/nonmethylated peptides through the adsorption of the SC4A-(Me3) complex.
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January 2025
Department of Laboratory Medicine, Clinical Laboratory Medicine Research Center of West China Hospital, Med+X Center for Manufacturing, Department of Rheumatology & Immunology, National Clinical Research Center for Geriatrics, Department of Gynecology of West China Tianfu Hospital, West China Hospital, Sichuan University, Chengdu, Sichuan 610041, China.
Homogeneous analysis techniques offer several advantages as alternatives to heterogeneous immunoassays, such as simplicity and rapidity. In this study, a visual homogeneous immunoassay without a labeling process was developed based on target-induced steric hindrance to regulate competitive recognition mechanism. Specifically, as the analyte concentration varies, the change of microenvironment based on steric hindrance could affect the recognition of Cu by signal probes.
View Article and Find Full Text PDFJ Biol Chem
January 2025
Department of Biochemistry and Molecular Biotechnology, University of Massachusetts Chan Medical School, Worcester, MA 01605, USA. Electronic address:
Transient protein-protein interactions play key roles in controlling dynamic cellular responses. Many examples involve globular protein domains that bind to peptide sequences known as Short Linear Motifs (SLiMs), which are enriched in intrinsically disordered regions of proteins. Here we describe a novel functional assay for measuring SLiM binding, called Systematic Intracellular Motif Binding Analysis (SIMBA).
View Article and Find Full Text PDFBiosens Bioelectron
January 2025
Department of Chemistry, Kansas State University, Manhattan, KS, 66502, USA. Electronic address:
Proteases are overexpressed at various stages of conditions such as cancers and thus can serve as biomarkers for disease diagnosis. Electrochemical techniques to detect the activity of extracellular proteases have gained attraction due to their multiplexing capability. Here we employ an electrochemical approach based on a 3 × 3 gold (Au) microelectrode array (MEA) functionalized with (2-aminoethyl)ferrocene (AEF) tagged specific peptide substrates to monitor cathepsin B (CB) protease activity.
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