Molecular characterization of the archaic HLA-B*73:01 allele reveals presentation of a unique peptidome and skewed engagement by KIR2DL2.

HLA class I alleles of archaic origin may have been retained in modern humans because they provide immunity against diseases to which archaic humans had evolved resistance. According to this model, archaic introgressed alleles were somehow distinct from those that evolved in African populations. Here we show that HLA-B*73:01, a rare allotype with putative archaic origins, has a relatively rare peptide binding motif with an unusually long-tailed peptide length distribution.

Conformational coupling between extracellular and transmembrane domains modulates holo-adhesion GPCR function.

Adhesion G Protein-Coupled Receptors (aGPCRs) are key cell-adhesion molecules involved in numerous physiological functions. aGPCRs have large multi-domain extracellular regions (ECRs) containing a conserved GAIN domain that precedes their seven-pass transmembrane domain (7TM). Ligand binding and mechanical force applied on the ECR regulate receptor function.

Biophysical Basis of Paracellular Barrier Modulation by a Pan-Claudin-Binding Molecule.

Claudins are a 27-member protein family that form and fortify specialized cell contacts in endothelium and epithelium called tight junctions. Tight junctions restrict paracellular transport across tissues by forming molecular barriers between cells. Claudin-binding molecules thus hold promise for modulating tight junction permeability to deliver drugs or as therapeutics to treat tight junction-linked disease.

Cryo-EM structures of Clostridium perfringens enterotoxin bound to its human receptor, claudin-4.

Clostridium perfringens enterotoxin (CpE) causes prevalent and deadly gastrointestinal disorders. CpE binds to receptors called claudins on the apical surfaces of small intestinal epithelium. Claudins normally regulate paracellular transport but are hijacked from doing so by CpE and are instead led to form claudin/CpE complexes.

Structural insights into terminal arabinosylation biosynthesis of the mycobacterial cell wall arabinan.

The emergence of drug-resistant strains exacerbates the global challenge of tuberculosis caused by Mycobacterium tuberculosis (Mtb). Central to the pathogenicity of Mtb is its complex cell envelope, which serves as a barrier against both immune system and pharmacological attacks. Two key components of this envelope, arabinogalactan (AG) and lipoarabinomannan (LAM) are complex polysaccharides that contain integral arabinan domains important for cell wall structural and functional integrity.