Phosphopantetheinyl transferase binding and inhibition by amidino-urea and hydroxypyrimidinethione compounds

Unlocking the brain's code: The crucial role of post-translational modifications in neurodevelopment and neurological function

Post-translational modifications (PTMs) represent a crucial regulatory mechanism in the brain, influencing various processes, including neurodevelopment and neurological function. This review discusses the effects of PTMs, such as phosphorylation, ubiquitination, acetylation, and glycosylation, on neurodevelopment and central nervous system functionality. Although neurodevelopmental processes linked to PTMs are complex, proteins frequently converge within shared pathways. These pathways encompass neurodevelopmental processes, signaling mechanisms, neuronal migration, and synaptic connection formation, where PTMs act as dynamic regulators, ensuring the precise execution of brain functions. A detailed investigation of the fundamental mechanisms governing these pathways will contribute to a deeper understanding of nervous system functions and facilitate the identification of potential therapeutic targets. A thorough examination of the PTM landscape holds significant potential, not only in advancing knowledge but also in developing treatments for various neurological disorders.

Targeting Siderophore Biosynthesis to Thwart Microbial Growth

The growing threat of antibiotic resistance has made treating bacterial and fungal infections increasingly difficult. With the discovery of new antibiotics slowing down, alternative strategies are urgently needed. Siderophores, small iron-chelating molecules produced by microorganisms, play a crucial role in iron acquisition and serve as virulence factors in many pathogens. Because iron is essential for microbial survival, targeting siderophore biosynthesis and transport presents a promising approach to combating drug-resistant infections. This review explores the key genetic and biochemical mechanisms involved in siderophore production, emphasizing potential drug targets within these pathways. Three major biosynthetic routes are examined: nonribosomal peptide synthetase (NRPS)-dependent, polyketide synthase (PKS)-based, and NRPS-independent (NIS) pathways. Additionally, microbial iron uptake mechanisms and membrane-associated transport systems are discussed, providing insights into their role in sustaining pathogenic growth. Recent advances in inhibitor development have shown that blocking critical enzymes in siderophore biosynthesis can effectively impair microbial growth. By disrupting these pathways, new antimicrobial strategies can be developed, offering alternatives to traditional antibiotics and potentially reducing the risk of resistance. A deeper understanding of siderophore biosynthesis and its regulation not only reveals fundamental microbial processes but also provides a foundation for designing targeted therapeutics. Leveraging these insights could lead to novel drugs that overcome antibiotic resistance, offering new hope in the fight against persistent infections.

A Nonessential Sfp-Type Phosphopantetheinyl Transferase Contributes Significantly to the Pathogenicity of Ralstonia solanacearum

4'-Phosphopantetheinyl transferases (PPTases) play important roles in the posttranslational modifications of bacterial carrier proteins, which are involved in various metabolic pathways. Here, we found that RsacpS and RspcpS encoded a functional AcpS-type and Sfp-type PPTase, respectively, in Ralstonia solanacearum GMI1000, and both are capable of modifying R. solanacearum AcpP1, AcpP2, AcpP3, and AcpP5 proteins. RspcpS is located on the megaplasmid, which does not affect strain growth and fatty acid synthesis but significantly contributes to the virulence of R. solanacearum and preferentially participates in secondary metabolism. We found that deletion of RspcpS did not affect the abilities of cellulose degradation, biofilm formation, and resistance to NaCl, sodium dodecyl sulfate, and H2O2 and attenuated R. solanacearum pathogenicity only in the assay of soil-drenching infection but not stem injection of tomato. It is hypothesized that RsPcpS plays a role in cell viability in complex environments and in the process during which the strain recognizes and approaches plants. These results suggest that both RsAcpS and RsPcpS may be potential targets for controlling diseases caused by R. solanacearum.

Redirecting raltitrexed from cancer cell thymidylate synthase to Mycobacterium tuberculosis phosphopantetheinyl transferase

There is a compelling need to find drugs active against Mycobacterium tuberculosis (Mtb). 4'-Phosphopantetheinyl transferase (PptT) is an essential enzyme in Mtb that has attracted interest as a potential drug target. We optimized a PptT assay, used it to screen 422,740 compounds, and identified raltitrexed, an antineoplastic antimetabolite, as the most potent PptT inhibitor yet reported. While trying unsuccessfully to improve raltitrexed's ability to kill Mtb and remove its ability to kill human cells, we learned three lessons that may help others developing antibiotics. First, binding of raltitrexed substantially changed the configuration of the PptT active site, complicating molecular modeling of analogs based on the unliganded crystal structure or the structure of cocrystals with inhibitors of another class. Second, minor changes in the raltitrexed molecule changed its target in Mtb from PptT to dihydrofolate reductase (DHFR). Third, the structure-activity relationship for over 800 raltitrexed analogs only became interpretable when we quantified and characterized the compounds' intrabacterial accumulation and transformation.

Teaching an old ‘doc’ new tricks for algal biotechnology: Strategic filter use enables multi-scale fluorescent protein signal detection

Fluorescent proteins (FPs) are powerful reporters with a broad range of applications in gene expression and subcellular localization. High-throughput screening is often required to identify individual transformed cell lines in organisms that favor non-homologous-end-joining integration of transgenes into genomes, like in the model green microalga Chlamydomonas reinhardtii. Strategic transgene design, including genetic fusion of transgenes to FPs, and strain domestication have aided engineering efforts in this host but have not removed the need for screening large numbers of transformants to identify those with robust transgene expression levels. FPs facilitate transformant screening by providing a visual signal indicating transgene expression. However, limited combinations of FPs have been described in alga and inherent background fluorescence from cell pigments can hinder FP detection efforts depending on available infrastructure. Here, an updated set of algal nuclear genome-domesticated plasmid parts for seven FPs and six epitope tags were generated and tested in C. reinhardtii. Strategic filter selection was found to enable detection of up to five independent FPs signals from cyan to far-red separately from inherent chlorophyll fluorescence in live algae at the agar plate-level and also in protein electrophoresis gels. This work presents technical advances for algal engineering that can assist reporter detection efforts in other photosynthetic host cells or organisms with inherent background fluorescence.