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X-ray crystal structures of two distinct steps in the catalytic cycle of non-ribosomal peptide synthetases are described, offering the potential to generate novel products through engineering enzyme activity. Holo-non-ribosomal peptide synthetases Non-ribosomal peptides, such as the antibiotic vancomycin and the immunosuppressant cyclosporin A, are peptidic secondary metabolites produced by microorganisms. Non-ribosomal peptide synthetases (NRPSs) are a family of large enzymes that utilize multiple catalytic domains to catalyse sequential steps in the biosynthetic pathway of this family of 'natural products'. Two papers in this issue of Nature present X-ray crystal structures that indicate that NRPSs are substantially more dynamic than previously believed. Andrew Gulick and colleagues studied two holo-non-ribosomal peptide synthetase modules, each revealing a distinct step in the catalytic cycle. Martin Schmeing and colleagues report several structures of LgrA, which is involved in the biosynthesis of the antibiotic gramicidin. Many important natural products are produced by multidomain non-ribosomal peptide synthetases (NRPSs) 1 , 2 , 3 , 4 . During synthesis, intermediates are covalently bound to integrated carrier domains and transported to neighbouring catalytic domains in an assembly line fashion 5 . Understanding the structural basis for catalysis with non-ribosomal peptide synthetases will facilitate bioengineering to create novel products. Here we describe the structures of two different holo-non-ribosomal peptide synthetase modules, each revealing a distinct step in the catalytic cycle. One structure depicts the carrier domain cofactor bound to the peptide bond-forming condensation domain, whereas a second structure captures the installation of the amino acid onto the cofactor within the adenylation domain. These structures demonstrate that a conformational change within the adenylation domain guides transfer of intermediates between domains. Furthermore, one structure shows that the condensation and adenylation domains simultaneously adopt their catalytic conformations, increasing the overall efficiency in a revised structural cycle. These structures and the single-particle electron microscopy analysis demonstrate a highly dynamic domain architecture and provide the foundation for understanding the structural mechanisms that could enable engineering of novel non-ribosomal peptide synthetases.

WEE2 oocyte meiosis inhibiting kinase is a well-conserved oocyte specific kinase with a dual regulatory role during meiosis. Active WEE2 maintains immature, germinal vesicle stage oocytes in prophase I arrest prior to the luteinizing hormone surge and facilitates exit from metaphase II arrest at fertilization. Spontaneous mutations at the WEE2 gene locus in women have been linked to total fertilization failure indicating that selective inhibitors to this kinase could function as non-hormonal contraceptives. Employing co-crystallization with WEE1 G2 checkpoint kinase inhibitors, we revealed the structural basis of action across WEE kinases and determined type I inhibitors were not selective to WEE2 over WEE1. In response, we performed in silico screening by FTMap/FTSite and Schrodinger SiteMap analysis to identify potential allosteric sites, then used an allosterically biased activity assay to conduct high-throughput screening of a 26 000 compound library containing scaffolds of known allosteric inhibitors. Resulting hits were validated and a selective inhibitor that binds full-length WEE2 was identified, designated GPHR-00336382, along with a fragment-like inhibitor that binds the kinase domain, GPHR-00355672. Additionally, we present an in vitro testing workflow to evaluate biological activity of candidate WEE2 inhibitors including; (1) enzyme-linked immunosorbent assays measuring WEE2 phosphorylation activity of cyclin dependent kinase 1 (CDK1; also known as cell division cycle 2 kinase, CDC2), (2) in vitro fertilization of bovine ova to determine inhibition of metaphase II exit, and (3) cell-proliferation assays to look for off-target effects against WEE1 in somatic (mitotic) cells. Summary sentence Oocyte specific WEE2 is critical for exit from metaphase II arrest in mammalian oocytes and selective inhibitors to this kinase can be developed into non-hormonal contraceptives for women that prevent fertilization.

2-Aminoimidazole (2-AI)-based compounds have been shown to efficiently disrupt biofilm formation, disperse existing biofilms, and resensitize numerous multidrug-resistant bacteria to antibiotics. Using and , we provide initial pharmacological studies regarding the application of a 2-AI as a topical adjuvant for persistent dermal infections. In vitro assays indicated that the 2-AI is nonbactericidal, resensitizes bacteria to antibiotics, does not harm the integument, and promotes wound healing. Furthermore, in vivo application of on swine skin caused no gross abnormalities or immune reactions. Taken together, these results indicate that represents a promising lead dermal adjuvant compound.

This study shows for the first time that an iminosugar exerts anti-spermiogenic effect, inducing reversible infertility in a species that is not related to C57BL/6 male mice. In CD rats, N-butyldeoxygalactonojirimycin (NB-DGJ) caused reversible infertility at 150 mg/kg/day when administered daily as single oral dose. NB-DGJ inhibited CD rat-derived testicular β-glucosidase 2 (GBA2) activity at 10 µM but did not inhibit CD rat-derived testicular ceramide-specific glucosyltransferase (CGT) at doses up to 1000 µM. Pharmacokinetic studies revealed that sufficient plasma levels of NB-DGJ (50 µM) were achieved to inhibit the enzyme. Fertility was blocked after 35 days of treatment and reversed one week after termination of treatment. The rapid return of fertility indicates that the major effect of NB-DGJ may be epididymal rather than testicular. Collectively, our in vitro and in vivo studies in rats suggest that iminosugars should continue to be pursued as potential lead compounds for development of oral, non-hormonal male contraceptives. The study also adds evidence that GBA2, and not CGT, is the major target for the contraceptive effect of iminosugars.

Many important natural products are produced by multidomain nonribosomal peptide synthetases (NRPSs)1–4. During synthesis, intermediates are covalently bound to integrated carrier domains and transported to neighboring catalytic domains in an assembly line fashion5. Understanding the structural basis for catalysis with NRPSs will facilitate bioengineering to create novel products. Here we describe the structures of two different holo-NRPSs modules, each revealing a distinct step in the catalytic cycle. One structure depicts the carrier domain cofactor bound to the peptide bond-forming condensation domain, whereas a second structure captures the installation of the amino acid onto the cofactor within the adenylation domain. These structures demonstrate that a conformational change within the adenylation domain guides transfer of intermediates between domains. Furthermore, one structure shows that the condensation and adenylation domains simultaneously adopt their catalytic conformations, increasing the overall efficiency in a revised structural cycle. These structures and single-particle electron microscopy analysis demonstrate a highly dynamic domain architecture and provide the foundation for understanding the structural mechanisms that could enable engineering novel NRPSs.

Patients with pulmonary hypertension due to interstitial lung disease were randomly assigned to inhaled treprostinil or placebo. At 16 weeks, there was a significant improvement in exercise capacity with inhaled treprostinil as compared with placebo as assessed by a 6-minute walk test.

Two-component, self-assembling nanoparticles represent a versatile platform for multivalent presentation of viral antigens. Computational design of protein nanoparticles with differing sizes and geometries enables combination with antigens of choice to test novel multimerization concepts in immunization strategies where the goal is to improve the induction and maturation of neutralizing antibody lineages. Here, we describe detailed antigenic, structural, and functional characterization of computationally designed tetrahedral, octahedral, and icosahedral nanoparticle immunogens displaying trimeric HIV envelope glycoprotein (Env) ectodomains. Env trimers, based on subtype A (BG505) or consensus group M (ConM) sequences and engineered with SOSIP stabilizing mutations, were fused to an underlying trimeric building block of each nanoparticle. Initial screening yielded one icosahedral and two tetrahedral nanoparticle candidates, capable of presenting twenty or four copies of the Env trimer. A number of analyses, including detailed structural characterization by cryo-EM, demonstrated that the nanoparticle immunogens possessed the intended structural and antigenic properties. When the immunogenicity of ConM-SOSIP trimers presented on a two-component tetrahedral nanoparticle or as soluble proteins were compared in rabbits, the two immunogens elicited similar serum antibody binding titers against the trimer component. Neutralizing antibody titers were slightly elevated in the animals given the nanoparticle immunogen and were initially more focused to the trimer apex. Altogether, our findings indicate that tetrahedral nanoparticles can be successfully applied for presentation of HIV Env trimer immunogens; however, the optimal implementation to different immunization strategies remains to be determined.

This large, systematic study of prenatal diagnosis shows that chromosomal microarray analysis provided additional, clinically significant cytogenetic information as compared with karyotyping but did not identify triploidies and balanced translocations. The development of array-based molecular cytogenetic techniques has improved the detection of small genomic deletions and duplications (called copy-number variants) that are not routinely seen on karyotyping, the standard cytogenetic analysis performed. Copy-number variants result in a variation from the expected number of copies of a segment of DNA (i.e., the number in a normal genome). Copy-number variants can be either benign or pathogenic, depending on their location and genetic content. They are identified with the use of chromosomal microarray analysis in which a test sample of DNA from the patient is compared directly or indirectly with a reference (normal) . . .

Patients with chronic liver disease (CLD) often present with significant frailty, sarcopenia, and impaired immune function. However, the mechanisms driving the development of these age-related phenotypes are not fully understood. To determine whether accelerated biological aging may play a role in CLD, epigenetic, transcriptomic, and phenotypic assessments were performed on the skeletal muscle tissue and immune cells of CLD patients and age-matched healthy controls. Accelerated biological aging of the skeletal muscle tissue of CLD patients was detected, as evidenced by an increase in epigenetic age compared with chronological age (mean +2.2 ± 4.8 years compared with healthy controls at −3.0 ± 3.2 years, p  = 0.0001). Considering disease etiology, age acceleration was significantly greater in both the alcohol-related (ArLD) ( p  = 0.01) and nonalcoholic fatty liver disease (NAFLD) ( p  = 0.0026) subgroups than in the healthy control subgroup, with no age acceleration observed in the immune-mediated subgroup or healthy control subgroup ( p  = 0.3). The skeletal muscle transcriptome was also enriched for genes associated with cellular senescence. Similarly, blood cell epigenetic age was significantly greater than that in control individuals, as calculated using the PhenoAge ( p  < 0.0001), DunedinPACE ( p  < 0.0001), or Hannum ( p  = 0.01) epigenetic clocks, with no difference using the Horvath clock. Analysis of the IMM-Age score indicated a prematurely aged immune phenotype in CLD patients that was 2-fold greater than that observed in age-matched healthy controls ( p  < 0.0001). These findings suggested that accelerated cellular aging may contribute to a phenotype associated with advanced age in CLD patients. Therefore, therapeutic interventions to reduce biological aging in CLD patients may improve health outcomes. Skeletal Muscle Ageing in CLD: Implications for Therapeutic Interventions Chronic liver disease, a long-term condition damaging the liver, is causing more deaths worldwide. Patients often develop immune dysfunction and sarcopenia. This study aimed to see if CLD patients show signs of fast biological ageing, particularly in muscles and the immune system. The research compared CLD patients to healthy people, looking at muscle samples, blood samples, and immune cells to check for ageing signs. Results showed that CLD patients have faster biological ageing in muscles and immune cells, with increased epigenetic age and more senescence-associated genes. This suggests that CLD speeds up the ageing process, which could explain the common occurrence of sarcopenia and immune dysfunction in these patients. Future implications include the possibility of developing treatments targeting the ageing process in CLD patients, offering hope for better health and quality of life This summary was initially drafted using artificial intelligence, then revised and fact-checked by the author.

Genome‐wide introgression and substitution lines have been developed in many plant species, enhancing mapping precision, gene discovery, and the identification and exploitation of variation from wild relatives. Created over multiple generations of crossing and/or backcrossing accompanied by marker‐assisted selection, the resulting introgression lines are a fixed genetic resource. In this study we report the development of spring wheat (Triticum aestivum L.) chromosome segment substitution lines (CSSLs) generated to systematically capture genetic variation from tetraploid (T. turgidum ssp. dicoccoides) and diploid (Aegilops tauschii) progenitor species. Generated in a common genetic background over four generations of backcrossing, this is a base resource for the mapping and characterization of wheat progenitor variation. To facilitate further exploitation the final population was genetically characterized using a high‐density genotyping array and a range of agronomic and grain traits assessed to demonstrate the potential use of the populations for trait localization in wheat. Core Ideas Precise genetic resources support downstream use of wheat progenitor variation. Wheat progenitor chromosome segment substitution lines are a trait mapping and introgression resource. Genotyping and trait validation highlight applicability for pre‐breeding and breeding.