Donor Strand Complementation and Calcium Ion Coordination Drive the Chaperone-free Polymerization of Archaeal Cannulae.

Cannulae are tubular protein filaments that accumulate on the extracellular surface of the hyperthermophilic archaeon during cell division. Cannulae have been postulated to act as a primitive extracellular matrix through which cells could communicate or exchange material, although their native biological function remains obscure. Here, we report cryoEM structural analyses of cannulae and of protein assemblies derived from recombinant cannula-like proteins.

Molecular dynamics and machine learning stratify motion-dependent activity profiles of S-layer destabilizing nanobodies.

Nanobody (Nb)-induced disassembly of surface array protein (Sap) S-layers, a two-dimensional paracrystalline protein lattice from , has been presented as a therapeutic intervention for lethal anthrax infections. However, only a subset of existing Nbs with affinity to Sap exhibit depolymerization activity, suggesting that affinity and epitope recognition are not enough to explain inhibitory activity. In this study, we performed all-atom molecular dynamics simulations of each Nb bound to the Sap binding site and trained a collection of machine learning classifiers to predict whether each Nb induces depolymerization.

Architecture of the Sap S-layer of revealed by integrative structural biology.

is a spore-forming gram-positive bacterium responsible for anthrax, an infectious disease with a high mortality rate and a target of concern due to bioterrorism and long-term site contamination. The entire surface of vegetative cells in exponential or stationary growth phase is covered in proteinaceous arrays called S-layers, composed of Sap or EA1 protein, respectively. The Sap S-layer represents an important virulence factor and cell envelope support structure whose paracrystalline nature is essential for its function.

Colibactin-driven colon cancer requires adhesin-mediated epithelial binding.

Various bacteria are suggested to contribute to colorectal cancer (CRC) development, including pks Escherichia coli, which produces the genotoxin colibactin that induces characteristic mutational signatures in host epithelial cells. However, it remains unclear how the highly unstable colibactin molecule is able to access host epithelial cells to cause harm. Here, using the microbiota-dependent ZEB2-transgenic mouse model of invasive CRC, we demonstrate that the oncogenic potential of pks E.