Protein Express (United States)

Virus-like particles (VLPs) are widely recognized as safe and versatile nanostructures with broad applications in vaccine development, gene delivery, and nanotechnology, but their production typically requires time-consuming procedures, incurs high costs, and yields products of limited purity. This article outlines a rapid, scalable, and cost-effective method for producing high-quality VLPs using the VP1s capsid protein from murine polyomavirus. The procedure comprises four principal stages: expression of the capsid protein in Escherichia coli, extraction and stabilization of the protein, purification to yield high-quality capsomeres, and controlled in vitro assembly of VLPs. Compared with conventional protocols that rely on in vivo assembly and labor-intensive purification procedures, such as ultracentrifugation- or affinity tag-based methods, the described approach provides a streamlined and rapid workflow that avoids affinity tags, achieves consistently high yields, and enables precise regulation of assembly conditions, resulting in a scalable and highly cost-efficient strategy for VLP production within 5 days. © 2026 Wiley Periodicals LLC. Basic Protocol 1: Expression and preparation of polyomavirus VP1 protein in E. coli Basic Protocol 2: Polymomavirus VP1 purification Basic Protocol 3: VP1 assembly Basic Protocol 4: Quality control.

The RAS-RAF-MEK-ERK mitogen-activated protein kinase (MAPK) pathway relays extracellular signals into a cellular response and its dysregulation leads to many pathologies, particularly cancer. Here, we determined cryo-EM structures of the MAP2K MEK1 activating its substrate MAPK ERK2, the final event in the cascade. We define the molecular details of specificity and phosphoryl transfer to the tyrosine of the ERK2 activation loop and examine the mechanism of substrate recognition using solution techniques and molecular dynamics. Binding of the substrate MAPK leads to release of the MAP2K catalytic machinery, explaining the mechanism of many disease-causing mutations, and ERK2 release is not required for nucleotide exchange, suggesting a processive mechanism. Our data advance the understanding of MAPK signalling and provide a starting point for drug development.

Welding is a ubiquitous technique in macroscopic materials manufacturing. However, replicating analogous processes at the molecular level—such as welding polymers by joining individual chains—remains a formidable challenge since Brownian motion disrupts the pre-organization of discrete molecular building blocks, which is a critical step prior to covalent welding. Here, we report the nanoscale welding of helical polymers through unidirectional supramolecular polymerization followed by dynamic covalent reconstruction. Our approach employs self-complementary H-bonding end groups to pre-organize discrete polymeric entities into one-dimensional supramolecular assemblies. These assemblies then template main-chain reconstruction via thiolate-disulfide exchange reactions, enabling covalent welding of discrete polymeric helices into larger architectures. This supramolecular welding strategy promotes controlled formation of covalent polymers with helical secondary structures, yielding ultrahigh-molecular-weight poly(disulfide)s (Mn > 1 MDa) that further fold and assemble into hierarchical globular architectures in solutions. The resulting helical polymers self-crosslink into an entangled network in the neat state, exhibiting an exceptionally broad temperature range of rubbery plateau and unusual thermo-stiffening features. These findings establish a supramolecular welding technique to covalently assemble helical polymers with nanoscale control and resembles various naturally occurring supramolecular synthesis processes based on the combination of noncovalent and dynamic covalent bonds.

ABSTRACTUsing account‐level data on millions of U.S. middle‐class investors over 2006 to 2018, we characterize the share of investable wealth that they hold in the stock market over their working lives. Relative to the 1990s, this share has both risen by 10% and become age‐dependent. The Pension Protection Act (PPA)—which allowed target date funds (TDFs) to be default options in retirement plans—played an important role: younger (older) workers starting at a firm after TDFs became the default option post‐PPA invested more (less) in stocks, in line with the TDF glidepath. In contrast, contribution rates changed little following the PPA.

De novo protein design is of fundamental interest to synthetic biology, with a plethora of computational methods of various degrees of generality developed in recent years. Here, we introduce AlphaDesign, a hallucination-based computational framework for de novo protein design developed with maximum generality and usability in mind, which combines AlphaFold with autoregressive diffusion models to enable rapid generation and computational validation of proteins with controllable interactions, conformations and oligomeric state without the requirement for class-dependent model re-training or fine-tuning. We apply our framework to design and systematically validate in vivo active inhibitors of a family of bacterial phage defense systems with toxic effectors called retrons, paving the way towards efficient, rational design of novel proteins as biologics.

This paper explores cross-platform sentiment analytics to unify customer feedback in digital business environments, enabling organizations to gain actionable insights from diverse data sources such as social media, reviews, and surveys. A systematic literature review synthesizes insights on sentiment analysis techniques, cross-platform data integration, and their applications in customer experience management. A proposed framework integrates these elements into a cohesive system for real-time feedback analysis. Application scenarios in retail, hospitality, and financial services illustrate the framework’s potential, suggesting up to 30% improvement in customer satisfaction and 25% increase in retention rates. The study contributes to the literature on digital business intelligence and offers practical guidelines for leveraging sentiment analytics to enhance customer-centric strategies.