To successfully colonize legume root nodules, rhizobia must effectively evade host-generated reactive oxygen species (ROS). LsrB, a redox regulator from , is essential for symbiosis with alfalfa (). The three cysteine residues in LsrB's substrate domain play distinct roles in activating downstream redox genes. The study found that LsrB's substrate-binding domain, dependent on the cysteine residue Cys146, is involved in oxidized glutathione (GSSG) resistance and alfalfa nodulation symbiosis. LsrB homologues from other rhizobia, with Cys172/Cys238 or Cys146, enhance GSSG resistance and complement mutant's symbiotic nodulation. Substituting amino acids in LsrB with Cys restores mutant phenotypes. The deletion mutant shows increased sensitivity to NCR247, suggesting an interaction with host plant-derived NCRs in alfalfa nodules. Our findings reveal that the key cysteine residue in the LsrB's substrate domain is vital for rhizobium-legume symbiosis.
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http://dx.doi.org/10.1021/acs.jafc.4c07925 | DOI Listing |
Nat Commun
January 2025
Life Sciences Institute, Department of Biochemistry and Molecular Biology, The University of British Columbia, Vancouver, BC, V6T 1Z3, Canada.
The heterodimeric Rab3GAP complex is a guanine nucleotide exchange factor (GEF) for the Rab18 GTPase that regulates lipid droplet metabolism, ER-to-Golgi trafficking, secretion, and autophagy. Why both subunits of Rab3GAP are required for Rab18 GEF activity and the molecular basis of how Rab3GAP engages and activates its cognate substrate are unknown. Here we show that human Rab3GAP is conformationally flexible and potentially autoinhibited by the C-terminal domain of its Rab3GAP2 subunit.
View Article and Find Full Text PDFNat Commun
January 2025
Laboratory of Membrane Biology and Biophysics, The Rockefeller University, New York, NY, USA.
Multidrug resistance-associated protein 2 (MRP2) is an ATP-powered exporter important for maintaining liver homeostasis and a potential contributor to chemotherapeutic resistance. Using cryogenic electron microscopy (cryo-EM), we determine the structures of human MRP2 in three conformational states: an autoinhibited state, a substrate-bound pre-translocation state, and an ATP-bound post-translocation state. In the autoinhibited state, the cytosolic regulatory (R) domain plugs into the transmembrane substrate-binding site and extends into the cytosol to form a composite ATP-binding site at the surface of nucleotide-binding domain 2.
View Article and Find Full Text PDFElife
January 2025
Department of Chemistry & Biochemistry, University of Delaware, Newark, United States.
The SARS-CoV-2 main protease (M or Nsp5) is critical for production of viral proteins during infection and, like many viral proteases, also targets host proteins to subvert their cellular functions. Here, we show that the human tRNA methyltransferase TRMT1 is recognized and cleaved by SARS-CoV-2 M. TRMT1 installs the ,-dimethylguanosine (m2,2G) modification on mammalian tRNAs, which promotes cellular protein synthesis and redox homeostasis.
View Article and Find Full Text PDFJ Agric Food Chem
January 2025
College of Light Industry and Food Engineering, Guangxi University, Nanning 530004, People's Republic of China.
Keratinases are valuable enzymes for converting feather keratin waste into bioactive products but often suffer from poor substrate specificity and low catalytic efficiency. This study reported the creating of a novel keratinase with targeted adherence and specific degradation on feather keratins by fusing prepeptidase C-Terminal (PPC) domain. A PPC domain of metalloprotease E423 specifically adsorbed feather keratins by hydrogen bonds and hydrophobic interactions in a time- and temperature-dependent manner.
View Article and Find Full Text PDFJ Cell Biochem
January 2025
Bioinformatics Division I Microbiology Division, ICMR-Regional Medical Research Centre, Bhubaneswar, Odisha, India.
B0AT1 (SLC6A19) is a major sodium-coupled neutral amino acid transporter that relies on angiotensin converting enzyme 2 (ACE2) or collectrin for membrane trafficking. Despite its significant role in disorders associated with amino acid metabolism, there is a deficit of comprehensive structure-function understanding of B0AT1 in lipid environment. Herein, we have employed molecular dynamics (MD) simulations to explore the architectural characteristics of B0AT1 in two distinct environments: a simplified POPC bilayer and a complex lipid system replicating the native membrane composition.
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