The predatory deltaproteobacterium Myxococcus xanthus uses a helically-trafficked motor at bacterial focal-adhesion (bFA) sites to power gliding motility. Using total internal reflection fluorescence and force microscopies, we identify the von Willebrand A domain-containing outer-membrane (OM) lipoprotein CglB as an essential substratum-coupling adhesin of the gliding transducer (Glt) machinery at bFAs. Biochemical and genetic analyses reveal that CglB localizes to the cell surface independently of the Glt apparatus; once there, it is recruited by the OM module of the gliding machinery, a heteroligomeric complex containing the integral OM β barrels GltA, GltB, and GltH, as well as the OM protein GltC and OM lipoprotein GltK. This Glt OM platform mediates the cell-surface accessibility and retention of CglB by the Glt apparatus. Together, these data suggest that the gliding complex promotes regulated surface exposure of CglB at bFAs, thus explaining the manner by which contractile forces exerted by inner-membrane motors are transduced across the cell envelope to the substratum.

Diverse bacteria assemble and secrete polysaccharides that alter their physiologies through modulation of motility, biofilm formation, and host immune system evasion. Most such pathways require outer membrane (OM) polysaccharide export (OPX) proteins for sugar-polymer transport to the cell surface.

Secretion of high-molecular-weight polysaccharides across the bacterial envelope is ubiquitous as it enhances prokaryotic survival in (a)biotic settings. Such polymers are often assembled by Wzx/Wzy- or ABC transporter-dependent schemes that implicate outer-membrane (OM) polysaccharide export (OPX) proteins in polymer translocation to the cell surface. In the social predatory bacterium Myxococcus xanthus, exopolysaccharide (EPS)-pathway WzaX, major spore coat (MASC)-pathway WzaS, and biosurfactant polysaccharide-pathway WzaB were herein found to be truncated OPX homologues of Escherichia coli Wza lacking OM-spanning α-helices. Comparative genomics across all bacteria, complemented with cryo-electron tomography cell-envelope analyses, revealed WzaX/S/B architecture to be the most common amongst three defined OPX-protein structural classes independent of periplasmic thickness. Fold-recognition and deep-learning analyses revealed the conserved M. xanthus proteins MXAN_7418/3226/1916 (encoded adjacent to WzaX/S/B) to be integral OM β-barrels, with structural homology to the poly-N-acetyl-D-glucosamine synthase-dependent pathway porin PgaA. Such porins were identified in bacteria near numerous genes for all three OPX-protein classes. Interior MXAN_7418/3226/1916 β-barrel electrostatics were found to match known properties of their associated polymers. With MXAN_3226 essential for MASC export, and MXAN_7418 absence shown herein to compromise EPS translocation, these data support a novel secretion paradigm for Wzx/Wzy-dependent pathways in which those containing an OPX component that cannot span the OM instead utilize a β-barrel porin to mediate polysaccharide transport across the OM.

Monkeypox is a viral zoonosis with symptoms that are reminiscent to those experienced in previous smallpox cases. GSAID databases (Global Initiative on Sharing Avian Influenza Data) was used to assess 630 genomes of MPXV. Six primary clades were inferred from the phylogenetic study, coupled with a lesser percentage in radiating clades. Individual clades that make up various nationalities may have formed as a result of a particular SNP hotspot type, which may have mutated in a particular population type. The most significant mutation, based on a mutational hotspot analysis, was found at G3729A and G5143A. The gene ORF138, which encodes the Ankyrin repeat (ANK) protein, was found to have the most mutations. This protein is known to mediate molecular recognition via protein-protein interactions. It was shown that 243 host proteins interacted with 10 monkeypox proteins identified as the hub proteins E3, SPI2, C5, K7, E8, G6, N2, B14, CRMB, and A41 through 262 direct connections. The interaction with chemokine system-related proteins provides further evidence that the human protein is being suppressed by the monkey pox virus in order to facilitate its survival against innate immunity. A few FDA-approved molecules were likely used as possible inhibitors after being researched for blocking F13, a significant envelope protein on the membrane of extracellular versions of virus. A total of 2500 putative ligands were docked individually with the F13 protein. The F13 protein and these molecules' interaction may help prevent the monkey pox virus from spreading. As a result, after being confirmed by experiments, these putative inhibitors might have an impact on the activity of these proteins and be utilised in monkeypox treatments.