Protein and Peptide Letters最新文献

Background: The Disintegrin and Metalloproteinase (ADAM) family, also known as the metalloproteinase/disintegrin/cysteine-rich (MDC) proteins, includes both secreted and transmembrane molecules involved in critical biological processes, such as cell migration, adhesion, and signaling. This study aimed to investigate the evolutionary relationships and structural characteristics of disintegrin and metalloproteinase proteins identified in the venom gland transcriptome of the scorpion Hemiscorpius lepturus.

Methods: Using bioinformatics tools, we analyzed the open reading frame, conserved motifs, and primary, secondary, and tertiary structures of these proteins. Five proteins, named HLDisMet1, HLDisMet2, HLDisMet3, HLDisMet4, and HLDisMet5, were identified. Their predicted 3-D structures were within normal ranges (Z-score between -4 to -9).

Results: Phylogenetic analysis revealed that HLDisMet1 shares similarities with proteins from various spider species (Nephila pilipes, Argiope bruennichi, Araneus ventricosus, and Trichonephila inaurata madagascariensis), HLDisMet2 with the scorpion Centruroides sculpturatus, HLDis- Met4 with the scorpion Tityus serrulatus, and HLDisMet5 with several snake species (Python bivittatus, Vipera anatolica senliki, Protobothrops mucrosquamatus, and Naja naja).

Conclusion: These findings highlight the significant similarities between HLDisMet proteins and those found in other venomous species, suggesting a complex and diverse evolutionary pathway for venom components. The cross-species conservation observed may indicate a convergent evolutionary strategy, where different species independently develop similar venom components to adapt to similar ecological niches or prey types. This study highlights the evolutionary significance of venom diversification and its potential applications in understanding venom biology across different species.

An error was found in the affiliations of the author in the article titled 'Investigation of the Expression and Regulation of SCG5 in the Context of the Chromogranin-Secretogranin Family in Malignant Tumors'', published in Protein and Peptide Letters, 2024, 31(9), 657-666 [1]. Details of the error and a correction are provided here. Original: *Address correspondence to these authors at the Department of Thoracic Surgery, The Sixth Affiliated Hospital of Nantong University, Yancheng Third People's Hospital, Yancheng 224000, P.R. China; E-mail: jxsongycsy@163.com (J.S.) Corrected: *Address correspondence to these authors at the Department of Thoracic Surgery, The Sixth Affiliated Hospital of Nantong University, Yancheng Third People's Hospital, Yancheng 224000, P.R. China; E-mail: jxsongycsy@163.com (J.S.); Department of General Medicine, The Sixth Affiliated Hospital of Nantong University, Yancheng Third People's Hospital, Yancheng 224000, P.R. China; E-mail: ycsy161317@163.com (X.L.). We regret the error and apologize to readers. The original article can be found online at: http://dx.doi.org/10.2174/0109298665325956240819064853 PMID: 39219421.

The SCG5 gene has been demonstrated to play an essential role in the development and progression of a range of malignant neoplasms. The regulation of SCG5 expression involves multiple biological pathways. According to relevant studies, SCG5 is differentially expressed in different cancers, and its up- or down-regulation may even affect tumour growth, invasion, and migration, which caught our attention. Therefore, we summarise the regulatory roles played by the SCG5 gene in a variety of cancers and the biological regulatory mechanisms associated with its possible promotion or inhibition of tumour biological behavior, to further explore the potential of SCG5 as a new tumour marker and hopefully provide theoretical guidance for subsequent disease research and treatment.

Objectives: In this study, we employed an in vitro culturing technique to investigate the impact of p53 on the modulation of growth-associated protein-43 (GAP-43) within the primary cortical neurons of rat specimens.

Methods: (1) Within the first 24 hours after birth, the bilateral cortex was extracted from newborn Wistar rats and primary cortical neurons were cultured and identified. (2) The changes in the mRNA and protein expressions of GAP-43 induced by p53 in rat primary cortical neurons cultured in vitro were identified utilizing real-time polymerase chain reaction and western blot techniques.

Results: (1) Lentiviral transfection of p53 within primary cortical neurons of rats elicited elevated levels of both mRNA and protein expressions of GAP-43, consequently culminating in a noteworthy augmentation of p53 expression. (2) The introduction of a p53 inhibitor in rat primary cortical neurons resulted in a reduction in both mRNA and protein expressions of GAP-43.

Conclusion: Within primary rat cortical neurons, p53 has the potential to prompt an augmentation in both the transcriptional and protein expression levels of the GAP-43 protein.

Background: Staphylococcus aureus is a common pathogen with strains that are resistant to existing antibiotics. MurJ from S. aureus (SaMurJ), an integral membrane protein functioning as Lipid II flippase, is a potential target for developing new antibacterial agents against this pathogen. Successful expression and purification of this protein shall be useful in the development of drugs against this target.

Objective: In this study, we demonstrated the optimized expression and purification procedures of SaMurJ, identified suitable detergent for extracting and solubilizing the protein, and examined the peptidisc system to generate a detergent-free environment.

Methods: SaMurJ fused with N-terminal ten-His tag was expressed without induction. Six detergents were selected for screening the most efficient candidate for extraction and solubilization of the protein. The thermostability of the detergent-solubilized protein was assessed by evaluated temperature incubation. Different ratios of peptidisc bi-helical peptide (NSPr) to SaMurJ were mixed and the on-bead peptidisc assembly method was applied.

Results: SaMurJ expressed in BL21(DE3) was confirmed by peptide fingerprinting, with a yield of 1 mg SaMurJ per liter culture. DDM was identified as the optimum detergent for solubilization and the nickel affinity column enabled SaMurJ purification with a purity of ~88%. However, NSPr could not stabilize SaMurJ.

Conclusion: The expression and purification of SaMurJ were successful, with high purity and good yield. SaMurJ can be solubilized and stabilized by a DDM-containing buffer.

Malaria caused by Plasmodium falciparum (Pf) is an illness that contributes significantly to the global health burden. Pf makes significant alterations to the host cell to meet its metabolic demands and escape the immune response of the host. These include the export of a large number of parasite proteins to the infected Red Blood Cells (iRBC). Variable Surface Antigens (VSAs), which are highly polymorphic protein families with important roles in immune evasion, form an important component of the exported proteins. A total of five protein families constitute the VSAs, viz. PfEMP1 (Pf erythrocyte membrane protein 1), RIFIN (repetitive interspersed family), STEVOR (sub-telomeric open reading frame), SURFIN (surface-associated interspersed gene family), and PfMC-2TM (Pf Maurer's cleft two transmembrane). With orthologues present in various simian-infecting species, VSAs take up a variety of domain topologies and organizational structures while exhibiting differential expressions throughout the parasite life cycle. Their expression varies across clinical isolates and laboratory strains, which suggests their crucial role in host cell survival and defense. Members of VSAs are reported to contribute significantly to disease pathogenesis through immune evasion processes like cytoadherence, iRBC sequestration in the host vasculature, rosetting, reduced erythrocyte deformability, and direct immunosuppression. In this study, we have gathered information on various aspects of VSAs, like their orthologues, domain architecture, surface topology, functions and interactions, and three-dimensional structures, while emphasizing discoveries in the field. Considering the vast repertoire of Plasmodial VSAs with new emergent functions, a lot remains unknown about these families and, hence, malaria biology.

Background: Early diagnosis remains difficult because the early symptoms of thymoma are atypical.

Objectives: This study aimed to analyze the changes of serum proteins in the early stage of thymoma (stage I/II) by proteomics method and to screen and validate candidate biomarkers.

Methods: Proteins were extracted from 8 sera patients with stage I/II thymoma and 9 healthy controls. The levels of serum proteins were detected by data-independent acquisition (DIA) quantitative proteomics techniques, and the differential proteins were identified. The proteomic results were verified by enzyme-linked immunosorbent assay. Additionally, differentially expressed proteins were analyzed using receiver operating characteristic curves (ROC).

Results: There were 80 differentially expressed proteins between the patients with thymoma and the healthy control group, among which 39 were up-regulated and 41 were down-regulated. Differential protein enrichment is involved in environmental information processing, signaling molecules and interactions, and in the body system and the immune system. The analysis of receptor working characteristic curves showed that the areas under the curve of CORO1A, SAA1 and LTA4H were all larger than 0.8, indicating that these proteins had good diagnostic value.

Conclusion: CORO1A, SAA1 and LTA4H may be new biomarkers for early screening of thymoma.

Phage therapy, a promising alternative to combat multidrug-resistant bacterial infections, harnesses the lytic cycle of bacteriophages to target and eliminate bacteria. Key players in this process are the phage lysis proteins, including holin, endolysin, and spanin, which work synergistically to disrupt the bacterial cell wall and induce lysis. Understanding the structure and function of these proteins is crucial for the development of effective therapies. Recombinant versions of these proteins have been engineered to enhance their stability and efficacy. Recent progress in the field has led to the approval of bacteriophage-based therapeutics as drugs, paving the way for their clinical use. These proteins can be combined in phage cocktails or combined with antibiotics to enhance their activity against bacterial biofilms, a common cause of treatment failure. Animal studies and clinical trials are being conducted to evaluate the safety and efficacy of phage therapy in humans. Overall, phage therapy holds great potential as a valuable tool in the fight against multidrug- resistant bacteria, offering hope for the future of infectious disease treatment.

Background: Resistance to anti-tumor agents targeting the epidermal growth factor receptor (EGFR) reduces treatment response and requires the development of novel EGFR antagonists. Mutant epidermal growth factor (EGF) forms with reduced agonistic activity could be promising agents in cancer treatment.

Methods: EGF D46G affinity to EGFR domain III was assessed with affinity chromatography. EGF D46G acute toxicity in Af albino mice at 320 and 3200 μg/kg subcutaneous doses was evaluated. EGF D46G activity in human epidermoid carcinoma cells at 10 ng/mL concentration in serum-free medium and in subcutaneous Ehrlich ascites carcinoma mice model at 320 μg/kg dose was studied.

Results: The D46G substitution decreases the thermal stability of EGF complexes with EGFR domain III by decreasing the ability of the C-terminus to be released from the intermolecular β- sheet. However, with remaining binding sites for EGFR domain I, EGF D46G effectively competes with other EGF-like growth factors for binding to EGFR and does not demonstrate toxic effects in mice. EGF D46G inhibits the proliferation of human epidermoid carcinoma cells compared to native EGF. A single subcutaneous administration of EGF D46G along with Ehrlich carcinoma cells injection inhibits the proliferation of these cells and delays tumor formation for up to seven days.

Conclusion: EGF D46G can be defined as a partial EGFR agonist as this mutant form demonstrates reduced agonistic activity compared to native EGF. The study emphasizes the role of the EGF C-terminus in establishing interactions with EGFR domain III, which are necessary for EGFR activation and subsequent proliferation of cells.

Background: Protein A resins have been widely used for product capture during mAb, bispecific antibody (bsAb), and Fc-fusion protein purification. While Protein A ligands mainly bind the Fc region, many of them can also bind the VH3 domain. During mAb/bsAb purification, certain truncated byproducts may contain the same Fc region as the product but fewer numbers of the VH3 domain. In such a scenario, VH3-binding Protein A resins provide a potential means for byproduct separation based on the difference in VH3-binding valency. As the ligands of different VH3-binding Protein A resins are derived from distinct domains of the native Protein A, it would be interesting to know whether they possess comparable capabilities for separating species with the same Fc region but different numbers of VH3 domain.

Objective: This study aims to explore the potential of different VH3-binding Protein A resins for separating antibody species with the same Fc region but different numbers of VH3 domain.

Methods: The VH3 Fab was released from a VH3-containing mAb by papain digestion. Post digestion, the released VH3 Fab was purified sequentially using CaptureSelect CH1-XL and MabSelect SuRe affinity chromatography. The purified VH3 Fab was used as the load material to assess the dynamic binding capacity (DBC) of five VH3-binding Protein A resins (i.e., Amshpere A3, Jetted A50, MabCaptureC, MabSelect and MabSelect PrismA). The potential of VH3-binding Protein A resins for separating species having the same Fc region but different numbers of VH3 domain was evaluated using an artificial mixture composed of the product and a truncated byproduct, which contained one and zero VH3 domain, respectively (both species contained the same Fc region). Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) was used to monitor Fab purification and separation of species containing the same Fc region but different numbers of VH3 domain.

Results: When loaded with an isolated VH3 Fab, different VH3-binding Protein A resins showed varied DBCs. Nevertheless, when these Protein A resins were used to separate a truncated byproduct, which contained the Fc region only without any VH3 domain, from the product, which included one VH3 domain in addition to the Fc region, they showed comparable capabilities for separating these two species.

Conclusion: Although different VH3-binding Protein A resins showed varied DBCs towards a VH3 Fab, they exhibited comparable capabilities for separating species with the same Fc region but different numbers of VH3 domain.