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The cryo-EM structure of Mycobacterium smegmatis arabinosyltransferase B EmbB involved in mycobacterial cell wall biosynthesis provides insights into the substrate binding and reaction mechanism. Mapping of the ethambutol resistance associated mutations onto the structure suggests the location of the drug binding site.

Metazoans have evolved endocrine systems that signal through dimerized receptors in response to cognate hormones. These authors characterize a nematode homolog of such human receptors, presenting the cryo-EM structure of an asymmetric dimer that embodies properties of the human receptors.

Bacterial resistance to polymyxin antibiotics is conferred by enzymes such as phosphoethanolamine transferases, which add positively charged phosphoethanolamine to lipid A. Here, the authors present the structure of one such enzyme in its liganded form, and propose an enzymatic mechanism that may be generally applicable to other phosphoform transferases.

Here, the authors present cryoEM structures of AftB, a key mycobacterial enzyme that adds terminal arabinose residues to the cell wall. In concert with functional assays and MD simulations, mechanistic insights are presented.

Here the authors investigate of the structural basis of substrate recognition and the catalytic mechanism of the mannosyltransferase PimE, which is crucial for the biosynthesis of phosphatidyl-myo-inositol mannosides (PIMs) in Mycobacterium tuberculosis.

Cryo-electron microscopy and molecular dynamics simulations reveal how MFSD2A transports essential omega-3 fatty acids across the blood–brain and blood–retina barriers as lysolipids.

FLVCR2 is expressed in the blood–brain barrier of mouse and human, and is the major mediator of choline uptake into the brain.

Bacterial cell shape is dependent on the formation of the extracellular sugar polymer called peptidoglycan. Here the authors describe RodA-PBP2, the enzymatic core of the elongasome, which is the complex responsible peptidoglycan synthesis, and utilize an integrated approach to investigate the mechanism of peptidoglycan biosynthesis.

Here it is shown that ion flux through the TrkH–TrkA complex is upregulated by ATP and downregulated by ADP; solving the X-ray crystal structures of the tetrameric TrkA ring in the absence and presence of TrkH suggests a mechanism by which ATP-induced conformational changes in TrkA augment the activity of TrkH.

SLAC1 is a plant ion channel that controls turgor pressure in the guard cells of plant stomata, thereby regulating the exchange of water vapour and photosynthetic gases in response to environmental signals. Here, the X-ray crystal structure of a bacterial homologue of SLAC1 has been solved, and structure-inspired mutagenesis has been used to analyse the conductance properties of the channel. The findings indicate that selectivity among different anions is largely a function of the energetic cost of ion dehydration.

Trimeric intracellular cation channels (TRICs) elicit K⁺ currents to counteract luminal negative potential during Ca²⁺release from intracellular stores. Here the authors present structures of prokaryotic TRICs in their open and closed states, obtaining molecular insight into TRICs’ function.

Cryo-electron microscopy structures of the bacterial O-antigen ligase WaaL, combined with genetics, biochemistry and molecular dynamics simulations, provide insight into the mechanism by which WaaL catalyses the biosynthesis of lipopolysaccharide.

The structure of the GABA_B receptor in an inactive state reveals, amongst other features, a latch between the two subunits that locks the transmembrane domain interface, and the presence of large phospholipids that may modulate receptor function.

Polyisoprenyl-glycosyltransferases (PI-GTs) catalyse the addition of sugar to lipid carriers, which is the first step in the production of sugar donors for glycosylation. Here Ardiccioni et al.present the structure of a bacterial PI-GT and propose a mechanistic basis for sugar transfer.

The transfer of a phosphate group from a CDP-linked donor to an acceptor alcohol is catalysed by CDP-alcohol phosphotransferases. Here, Sciara et al. report crystal structures of a CDP-alcohol phosphotransferase, define roles of conserved residues and propose a mechanism of action for this protein family.

Here, the X-ray crystal structure of TrkH is solved, a protein that mediates potassium uptake in Vibrio parahaemolyticus, a bacterium. The selectivity filter of the ion transporter is very similar to what is seen in (much simpler) potassium ion channels, but it is significantly shorter. Biochemical studies were performed to explore the molecular basis of K⁺ selectivity, and it is believed that a novel gating mechanism is involved.

The X-ray crystal structure of a rat neurotensin receptor in complex with the C-terminal portion of neurotensin is presented; this is the first structure of a member of the β group of class A G-protein-coupled receptors.

Carotenoid biosynthesis requires isomerization of the central double bond. Informatic, spectroscopic and functional characterization of Z-ISO, a protein involved in the process, demonstrates that it is a standalone enzyme with unusual heme-dependent chemistry.

Inhibitors of the bile acid transporter ASBT may be useful therapeutics for treating hypercholesterolaemia and type 2 diabetes; here, two X-ray crystal structures of an ASBT homologue from Yersinia frederiksenii are solved.