Prokaryotic membranes are fundamental to cellular organization and function, serving as dynamic platforms for transport, energy conservation, signaling, environmental adaptation, etc. This review provides an overview of prokaryotic membrane architecture, highlighting the structural diversity of bacterial and archaeal cell envelopes, focusing on the cytoplasmic membranes and the distinct lipid chemistries that define them. By describing the general pathways for fatty acid and phospholipid biosynthesis, we emphasize the universal role for the lipid intermediates lysophosphatidic acid and phosphatidic acid, as well as the major lipid species phosphatidylethanolamine, phosphatidylglycerol, and cardiolipin of the diderm bacteria Escherichia coli . Besides synthesis, lipid membrane insertion is described, highlighting recent findings regarding lipid leaflet distribution, asymmetry, and intermembrane transport. Altogether, these processes provide a general overview of lipid composition and function of proliferating cells.
Glycans are the main components of the fungal cell wall and play a central role in fungal pathogenesis, making atomic‐level structural and dynamic insight into these biopolymers essential for the development of new antifungal therapeutics. 1 H‐detected solid‐state NMR (ssNMR) at fast magic‐angle spinning (MAS) offers an unprecedented opportunity to study glycan site, specifically at atomic resolution in intact fungal cell walls. However, the 1 H resolution and sensitivity in ssNMR are often limited for detailed studies, especially for rigid and highly heterogeneous samples, such as intact fungal cells. Here, we conducted a detailed study on 1 H line width and 1 H T ′ 2 coherence times in the rigid core of the human pathogenic Candida albicans fungal glycans at 60–150 kHz MAS rates and partial fungal cell wall deuteration schemes. We showcased the possibilities and limitations of 1 H‐detected multidimensional 1 H/ 13 C chemical shift assignment experiments for rigid cell wall glycans. Furthermore, we probed dynamics using relaxation measurements, providing access to motions spanning from nanoseconds to microseconds. Overall, we demonstrated significant methodological advances in 1 H‐detected ssNMR spectroscopy, achieving unprecedented 1 H resolution of rigid glycans in intact fungal cell walls. These developments could be applicable for ssNMR detailed studies of intact cell walls in other human pathogens.
Host–microbe interactions refer to the dynamic relationships between hosts, such as humans, and the microorganisms present on or inside them. These associations can be beneficial, like gut bacteria facilitating digestion, or harmful, such as pathogens leading to disease. This review focuses on the reproductive tract, specifically the vaginal microbiome. Typically, a healthy vaginal microbiome is dominated by Lactobacillus species, which help protect against infections by pathogens. Dysbiosis, or a microbial imbalance, allows pathogens to invade. One such pathogen is Streptococcus agalactiae (group B Streptococcus , GBS), which can colonize the vaginal microbiome and cause infections. GBS infection during pregnancy is particularly concerning and is a major cause of adverse pregnancy outcomes. This review will explore host–microbe interactions in the vaginal microbiome, with an emphasis on GBS infection, its virulence, and current treatment strategies.
Hybridization‐based nucleic acid detection remains central to molecular diagnostics but is often limited by slow kinetics, diminished sensitivity toward structured or double‐stranded targets and low selectivity in recognizing single‐nucleotide variation (SNV) at ambient temperatures. Here we introduce a DNA platform‐assisted cooperative probe (PCP) that enhances the performance of conventional molecular beacon (MB) probes through cooperative analyte binding mediated by a DNA scaffold. The PCP architecture spatially organizes two analyte‐binding arms (F and U) on a dsDNA platform for cooperative tight binding of nucleic acid analytes, which enables the use of a short platform‐detached strand m for highly selective SNV recognition. Using clinically relevant targets from Mycoplasma genitalium (23S rRNA fragment) and Neisseria gonorrhoeae (penA gene fragment), we demonstrate that PCP improves SNV selectivity from 10% to 14% for MB probe up to 99%, and lowers the limit of detection by up to an order of magnitude but does not significantly improve hybridization rate. The PCP sensor further enables room‐temperature detection of double‐stranded polymerase chain reaction (PCR) amplicons. These results establish DNA platform‐based probe organization as an advantageous strategy to resolve the affinity/specificity trade‐off in hybridization‐based diagnostics.
Among the promising microbial platforms to produce value‐added products from CO 2 , chemolithoautotrophic bacteria, such as Cupriavidus necator H16 ( C. necator ), stand out due to their ability to fix CO 2 via the Calvin–Benson–Bassham (CBB) cycle. Although C. necator has been extensively studied as a biotechnological production host, several of its biosynthetic pathways remain incompletely characterized at the biochemical level. This includes l ‐methionine biosynthesis, for which genome‐based functional annotations of key enzymes have not been validated experimentally. In this study, we identified and characterized Cn MetXS, a homoserine O ‐succinyltransferase involved in l ‐methionine biosynthesis in C. necator . Biochemical characterization demonstrated that Cn MetXS catalyzes the transsuccinylation of l ‐homoserine to O ‐succinyl‐ l ‐homoserine but exhibits no transacetylase activity. Additionally, we determined the apo crystal structure of Cn MetXS at 1.86 Å resolution, revealing a homodimer with a MetX‐G2 active‐site architecture and distinct conformations of the active‐site lid region. Structural analysis and docking suggest that Arg335 stabilizes the succinylated enzyme intermediate and explains the observed succinyl‐CoA specificity. Together, these results establish the function of Cn MetXS and pave the way for metabolic engineering strategies to produce l ‐methionine in C. necator .
