Maupin, C. M. | bioRxiv Science

bioRxiv2026

INTEGRATOR: Structural Elucidation of the INO80 Chromatin Remodeler via Experimentally Guided Molecular Simulations

The INO80 chromatin remodeling complex plays a central role in DNA repair, transcription, and replication. Yet, a comprehensive understanding of its structural organization remains incomplete due to the dynamic nature of several of its subunits and the sharing of several subunits with related remodeling complexes. Here, we report a computational model of the three-dimensional structure of the S. cerevisiae INO80 complex using an integrative approach that combines experimental crosslinking mass spectrometry, molecular docking, and molecular dynamics simulations. Our results reveal the spatial and dynamical organization of key modules--ARP8, ARP5, NHP10, and RVB1/2--within the intact complex. The resulting structural model agrees with crosslinking constraints, highlighting the architecture of the previously uncharacterized NHP10 module. This module, including the C-terminal region of the Ino80 scaffolding protein, has remained elusive due to its intrinsic flexibility and lack of high-resolution structural data. To facilitate this integrative modeling workflow and make it broadly accessible, we presented INTEGRATOR: (INTEGRAtive TempOral and stRuctural Analysis of protein modules), a versatile workflow package designed as a tool to elucidate the structure and dynamics of large, flexible macromolecular assemblies using well-established softwares. Our findings demonstrate the power of integrative modeling in resolving the role of the highly disordered NPH10 module in recruiting other dynamic modules into INO80 large protein assemblies and offer a generalizable framework for determining the architecture of similarly complex and heterogeneous molecular machines. This work carries broad implications for understanding the structural basis of chromatin regulation in microbial organisms and the implications for the dysregulation in diseases such as cancer.

biophysics↗

bioRxiv2025

A Multiscale Framework for Uncovering Surfactant Mediated Viral Capsid Disruption

Disinfection remains a critical strategy for controlling the transmission of infectious diseases. However, small non-enveloped viruses exhibit exceptional resistance to many disinfectants, often requiring harsh protein-disrupting chemicals for effective inactivation, thereby limiting their applicability in personal care products due to associated side effects. Sodium dodecyl sulphate (SDS) is a widely used anionic surfactant known for its virucidal efficacy; however, the molecular details of its action against robust non-enveloped viruses remain poorly understood, limiting efforts to design safer and more targeted antiviral formulations. In this study, a multiscale simulation approach combining a novel atomic-resolution icosahedral "scaffold framework" and coarse-grained modelling was developed to elucidate the mechanism of SDS-driven disruption of MS2 bacteriophage capsid, a surrogate for non-enveloped viruses. Experimental analyses including dynamic light scattering and transmission electron microscopy revealed that SDS inactivates MS2 in a strongly pH-dependent manner, triggering capsid disassembly at acidic pH while leaving particles largely intact at neutral pH. Molecular dynamics simulations demonstrated that SDS micelles preferentially associate with hexameric pores and inter-dimer clefts under acidic conditions, where protonation of acidic residues weakens the electrostatic network of the capsid surface. Together, these findings provide a detailed molecular framework for SDS virucidal action and highlight the importance of environmental pH in modulating surfactant-virus interactions. These insights offer a foundation for designing next-generation antiviral surfactants with improved efficacy and biocompatibility.

biophysics↗