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  • Ebooks (Sách điện tử)

  • Structural insights into the initiation of free radical formation in the Class Ib ribonucleotide reductases

    • Authors : Yadav, Lumbini R. (2023)

  • Class I ribonucleotide reductases consisting of R1 and R2 subunits convert ribonucleoside diphosphates to deoxyribonucleoside diphosphates involving an intricate free radical mechanism. The generation of free radicals in the Class Ib ribonucleotide reductases is mediated by reaction involving di-manganese ions in the R2 subunits and is externally assisted by flavodoxin-like NrdI subunit. This is unlike Class Ia ribonucleotide reductases, where the free radical generation&#x...
  • Journal article

  • Structure and function of a hexameric cyanophycin synthetase 2

    • Authors : Markus, Linda M. D.  (2023)

  • Cyanophycin is a natural polymer composed of a poly-aspartate backbone with arginine attached to each of the aspartate sidechains. Produced by a wide range of bacteria, which mainly use it as a store of fixed nitrogen, it has many promising industrial applications. Cyanophycin can be synthesized from the amino acids Asp and Arg by the widespread cyanophycin synthetase 1 (CphA1), or from the dipeptide β-Asp-Arg by the cyanobacteria...
  • Ebooks (Sách điện tử)

  • The structure of the neurotoxin palytoxin determined by MicroED

    • Authors : Gillman, Cody (2023)

  • Palytoxin (PTX) is a potent neurotoxin found in marine animals that can cause serious symptoms 17 such as muscle contractions, haemolysis of red blood cells and potassium leakage. Despite years 18 of research, very little is known about the mechanism of PTX. However, recent advances in the 19 field of cryoEM, specifically the use of microcrystal electron diffraction (MicroED), have allowed 20 us to determine the structure of PTX. It was&#x...
  • Journal Article

  • Structure of full-length cobalamin-dependent methionine synthase and cofactor loading captured in crystallo

    • Authors : Mendoza, Johnny (2023)

  • Cobalamin-dependent methionine synthase (MS) is a key enzyme in methionine and folate one-carbon metabolism. MS is a large multi-domain protein capable of binding and activating three substrates: homocysteine, folate, S-adenosylmethionine for methylation. Achieving three chemically distinct methylations necessitates significant domain rearrangements to facilitate substrate access to the cobalamin cofactor at the right time. The distinct conformations required for each r...
  • Journal Article

  • Structure and function of a YeeE-YeeD complex for sophisticated thiosulfate uptake

    • Authors : Ikei, Mai (2023)

  • From bacteria to eukaryotes, sulfur is a vital element for cellular activities. For example, sulfur34 containing biomolecules, such as L-cysteine, L-methionine, thiamine, glutathione, and biotin, play a 35 variety of essential roles in cells (1). Bacteria and plants can utilize L-cysteine as a source of sulfate, 36 but they also have sulfur assimilation pathways to synthesize L-cysteine from inorganic sulfur 37 compounds. In bacteria, L-cysteine...
  • Journal article

  • Structural basis for reduced ribosomal A-site fidelity in response to P-site codon-anticodon mismatches

    • Authors : Nguyen, Ha An (2023)

  • Rapid and accurate translation is essential in all organisms to produce properly folded and functional proteins. mRNA codons that define the protein coding sequences are decoded by tRNAs on the ribosome in the aminoacyl (A) binding site. The mRNA codon and the tRNA anticodon interaction is extensively monitored by the ribosome to ensure accuracy in tRNA selection. While other polymerases that synthesize DNA and RNA can correct for...
  • Journal article

  • Structure of a dimeric ABC transporter

    • Authors : Bickers, Sarah C.  (2023)

  • ATP binding cassette (ABC) proteins generally couple ATP hydrolysis to the active 20 transport of solutes across cellular membranes. All ABC proteins contain a core structure of two 21 transmembrane domains (TMD1, TMD2) and two nucleotide binding domains (NBD1, NBD2), 22 and many ABC proteins contain additional domains. Some members of the C subfamily of ABC 23 (ABCC) proteins, such as the multidrug resistant protein 1 (MRP1), con...
  • Journal article

  • Structure of a Membrane Tethering Complex Incorporating Multiple SNAREs

    • Authors : DAmico, Kevin A. (2023)

  • Most membrane fusion reactions in eukaryotic cells are mediated by membrane tethering 17 complexes (MTCs) and SNARE proteins. MTCs are much larger than SNAREs and are thought 18 to mediate the initial attachment of two membranes. Complementary SNAREs then form 19 membrane-bridging complexes whose assembly draws the membranes together for fusion. Here, 20 we present a cryo-EM structure of the simplest known MTC, the 255-kDa Dsl1 complex...