Enzyme mechanisms articles within Nature Communications

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  • Article
    | Open Access

    Gram-positive bacteria contain a transcription factor HelD that is able to remove and recycle stalled transcription complexes. Here the authors provide mechanistic insights into this process by determining the cryo-EM structures of the Bacillus subtilis RNA polymerase (RNAP) elongation complex and the RNAP-HelD transcription recycling complex and propose a model of HelD catalysed transcription recycling.

    • Timothy P. Newing
    • , Aaron J. Oakley
    •  & Peter J. Lewis
  • Article
    | Open Access

    Heme biosynthesis depends on iron-sulfur (Fe-S) cluster biogenesis but the molecular connection between these pathways is not fully understood. Here, the authors show that the heme biosynthesis enzyme ALAD contains an Fe-S cluster, disruption of which reduces ALAD activity and heme production in human cells.

    • Gang Liu
    • , Debangsu Sil
    •  & Tracey Ann Rouault
  • Article
    | Open Access

    C-nucleosides are analogues of the canonical N-nucleosides and, despite their synthetic value, biocatalysis has not targeted them yet. Here, the authors report a pseudouridine monophosphate C-glycosidase enzyme for selective 5-β-C-glycosylation of uracil and its derivatives from pentose 5- phosphate substrates.

    • Martin Pfeiffer
    •  & Bernd Nidetzky
  • Article
    | Open Access

    Bacterial heterodimeric tryptophan-containing diketopiperazines (HTDKPs) are bioactive natural products that are difficult to access chemically. Here, the authors identify a family of three related HTDKP-forming cytochrome P450s and engineer key amino acid residues to produce distinct diketopiperazines frameworks.

    • Chenghai Sun
    • , Zhenyao Luo
    •  & Xudong Qu
  • Article
    | Open Access

    How clamp conformation is regulated in the transcription cycle of stalk-containing archaeal and eukaryotic RNA polymerase (RNAP) systems is still not well understood. Here, the authors combine cryo-EM, X-ray crystallography and photo-crosslinking assays to structurally characterise RNAP, the RNAP-TFEα binary and RNAP-TFEα-promoter DNA ternary complexes from the archaea Thermococcus kodakarensis and enables them to describe the dynamic conformational changes of the general transcription factor TFEα and RNAP during the early stage of transcription cycle.

    • Sung-Hoon Jun
    • , Jaekyung Hyun
    •  & Katsuhiko S. Murakami
  • Article
    | Open Access

    Pathogenic IgA1 metalloproteases block the initial host immune response by cleaving host IgA1. Using cryoEM, the authors here provide structural insights into the substrate recognition mechanism of Streptococcus pneumoniae IgA1 protease, and develop a protease-inhibiting antibody.

    • Zhiming Wang
    • , Jeremy Rahkola
    •  & Elan Eisenmesser
  • Article
    | Open Access

    Type I-C Cascade (the CRISPR-associated complex for antiviral defense) is a minimal system, comprising only three unique Cas proteins. Cryo-EM structure of the Desulfovibrio vulgaris type I-C Cascade reveals the molecular mechanisms that underlie RNA-directed complex assembly.

    • Roisin E. O’Brien
    • , Inês C. Santos
    •  & David W. Taylor
  • Article
    | Open Access

    Here the authors show that the preference of yeast chromatin remodeler ISW1a for dinucleosomes hinges on conformational changes that occur in the transition from binding mononucleosomes to dinucleosomes. These changes are critical for ISW1a organizing chromatin at promoters and regulating transcription in conjunction with other chromatin remodelers.

    • Saurabh K. Bhardwaj
    • , Solomon G. Hailu
    •  & Blaine Bartholomew
  • Article
    | Open Access

    The SARS-CoV-2 main protease (Mpro) is one of two cysteine proteases essential for viral replication. Here, the authors determine the crystal structure of an Mpro acyl intermediate with its native C-terminal autocleavage sequence and the structure of a product bound active site mutant (C145A), which are of interest for antiviral drug development.

    • Jaeyong Lee
    • , Liam J. Worrall
    •  & Natalie C. J. Strynadka
  • Article
    | Open Access

    Biosynthesis of biotin precursor, pimelate moiety, is elucidated in Escherichia coli and Bacillus subtilis, but not understood in alphaproteobacteria. Here, the authors show that BioZ, a 3-ketoacyl-ACP synthase, catalayses pimeloyl-thioester synthesis in alphaproteobacteria using malonyl-ACP and glutaryl-CoA that is derived from lysine degradation.

    • Yuanyuan Hu
    •  & John E. Cronan
  • Article
    | Open Access

    The conserved SAM motif of Polycomb Repressive Complex 1 subunit Ph has been shown to play an important role in chromatin organization. Here, the authors study the effect of Ph SAM on chromatin in vitro, showing that it induces the formation of concentrated, phase-separated condensates, which enhance the ubiquitin ligase activity of PRC1.

    • Elias Seif
    • , Jin Joo Kang
    •  & Nicole J. Francis
  • Article
    | Open Access

    β-phosphoglucomutase (βPGM) from Lactococcus lactis is a phosphoryl transfer enzyme required for catabolism of trehalose and maltose. Coupled analyses of multiple βPGM structures and enzymatic activity lead to the proposal of allomorphy — a post-translational mechanism controlling enzyme activity.

    • Henry P. Wood
    • , F. Aaron Cruz-Navarrete
    •  & Jonathan P. Waltho
  • Article
    | Open Access

    The conserved eukaryotic heterotrimeric NatC complex co-translationally acetylates the N-termini of numerous target proteins. Here, the authors provide insights into the catalytic mechanism of NatC by determining the crystal structures of Saccharomyces cerevisiae NatC in the absence and presence of cofactors and peptide substrates and reveal the molecular basis of substrate binding by further biochemical analyses.

    • Stephan Grunwald
    • , Linus V. M. Hopf
    •  & Oliver Daumke
  • Article
    | Open Access

    Human Microrchidia 4 (MORC4) ATPase has been implicated in acute and chronic pancreatitis, inflammatory disorders and cancer. Here the authors describe the structure–function relationship of MORC4 and define the molecular mechanism for MORC4 activation.

    • Adam H. Tencer
    • , Khan L. Cox
    •  & Tatiana G. Kutateladze
  • Article
    | Open Access

    Human steroid 5α-reductase 2 (SRD5A2) is an integral membrane enzyme and catalyzes 5α-reduction of testosterone to dihydrotestosterone. Structural analysis accompanied by computational and mutagenesis studies reveal the mechanisms of catalysis and inhibition by clinically relevant drugs targeting SRD5A2.

    • Qingpin Xiao
    • , Lei Wang
    •  & Cheng Zhang
  • Article
    | Open Access

    Telomerase enzymes add telomeric repeats to the end of linear chromosomes. Here the authors reveal mechanisms by which oxidized dNTPs and therapeutic dNTPs inhibit telomerase-mediated telomere elongation.

    • Samantha L. Sanford
    • , Griffin A. Welfer
    •  & Patricia L. Opresko
  • Article
    | Open Access

    The respiratory complex I (NADH:ubiquinone oxidoreductase) is a large redox-driven proton pump that initiates respiration in mitochondria. Here, the authors present the 3.0 Å cryo-EM structure of complex I from mouse heart mitochondria with the ubiquinone-analogue inhibitor piericidin A bound in the active site and with kinetic measurements and MD simulations they further show that this inhibitor acts competitively against the native ubiquinone-10 substrate.

    • Hannah R. Bridges
    • , Justin G. Fedor
    •  & Judy Hirst
  • Article
    | Open Access

    Oxepinamides are a class of fungal oxepins with biological activities. Here, the authors elucidate the biosynthetic pathway of oxepinamide F from Aspergillus ustus and show that it involves enyme-catalysed oxepin ring formation, hydroxylation-induced double bond migration, epimerization and methylation.

    • Liujuan Zheng
    • , Haowen Wang
    •  & Shu-Ming Li
  • Article
    | Open Access

    Neisseria meningitidis capsular polysaccharide (CPS) is a major virulence factor and vaccine formulations against Neisseria meningitidis serogroup A (NmA) contain O-acetylated CPS. Here, the authors provide mechanistic insights into CPS O-acetylation in NmA by determining the crystal structure of the O-acetyltransferase CsaC and NMR measurements further reveal that the CsaC-mediated reaction is regioselective for O3 and that the O4 modification results from spontaneous O-acetyl migration.

    • Timm Fiebig
    • , Johannes T. Cramer
    •  & Martina Mühlenhoff
  • Article
    | Open Access

    Metalloenzymes often show different catalytic activities in the presence of non-native metal ions. Here, the authors report structures of carbonic anhydrase bound to zinc and several other metal ions and demonstrate that metal ion coordination geometries directly impact catalytic activity of the enzyme.

    • Jin Kyun Kim
    • , Cheol Lee
    •  & Chae Un Kim
  • Article
    | Open Access

    The origin recognition complex (ORC) is essential for loading the Mcm2–7 replicative helicase onto DNA during DNA replication initiation. Here, the authors describe several cryo-electron microscopy structures of Drosophila ORC bound to DNA and its cofactor Cdc6 and also report an in vitro reconstitution system for Drosophila Mcm2–7 loading, revealing unexpected features of ORC’s DNA binding and remodeling mechanism during Mcm2–7 loading.

    • Jan Marten Schmidt
    •  & Franziska Bleichert
  • Article
    | Open Access

    Complex I (NADH:ubiquinone oxidoreductase) is the first enzyme of the respiratory chain in bacteria and mitochondria. Here, the authors present cryo-EM and crystal structures of T. thermophilus complex I in different conformational states and further analyse them by Normal Mode Analysis and molecular dynamics simulations and conclude that quinone redox reactions are important for the coupling mechanism of complex I.

    • Javier Gutiérrez-Fernández
    • , Karol Kaszuba
    •  & Leonid A. Sazanov
  • Article
    | Open Access

    Mevalonate diphosphate decarboxylase (MDD) is a key enzyme in the mevalonate pathway and catalyses the decarboxylation of mevalonate-5-diphosphate to isopentenyl diphosphate. Here, the authors provide insights into the conformational changes that occur during substrate binding of MDD and the subsequent enzymatic reaction steps by determining the substrate and intermediate bound crystal structures of Enterococcus faecalis MDD.

    • Chun-Liang Chen
    • , Lake N. Paul
    •  & Cynthia V. Stauffacher
  • Article
    | Open Access

    Terpene cyclases catalyze the formation of diverse hydrocarbon scaffolds found in terpenoids. Here, the authors report the cryptic function of class I terpene cyclases as aromatic prenyltransferases and the universality of this cryptic feature is confirmed using enzymes from different sources.

    • Haibing He
    • , Guangkai Bian
    •  & Tiangang Liu
  • Article
    | Open Access

    Monooxygenases catalyse the hydroxylation of C-H bonds using oxygen as a co-substrate, which, in turn, is unavailable for anaerobic bacteria. Here, the authors report a three-step reaction cascade involving two hydroxylases and one dehydratase which hydroxylate the C26 methyl group of cholesterol with water as a co-substrate.

    • Christian Jacoby
    • , Sascha Ferlaino
    •  & Matthias Boll
  • Article
    | Open Access

    Human Histone Deacetylases (HDACs) regulate gene expression and are important drug targets. Here, the authors combine NMR measurements, enzymatic assays and molecular dynamics simulations and show that HDAC8 samples a catalytically active and an inactive state and further demonstrate that mutations and ligand binding alter the populations of the two states, which is of interest for inhibitor design.

    • Nicolas D. Werbeck
    • , Vaibhav Kumar Shukla
    •  & D. Flemming Hansen
  • Article
    | Open Access

    During eukaryotic chromosome replication cells utilize ring-shaped CMG helicase that separates the two strands of the DNA double helix. Here the authors reveal that CMG helicase activity is inhibited by duplex DNA engagement at the fork, which is relieved by binding of RPA to the lagging-strand template.

    • Hazal B. Kose
    • , Sherry Xie
    •  & Hasan Yardimci
  • Article
    | Open Access

    Glutaredoxins are a family of essential enzymes divided into two major classes with either a CGFS or a CxxC active site, of which only the latter exhibits oxidoreductase activity. Here the authors address the structural basis for the functional difference between the two classes of glutaredoxins.

    • Daniel Trnka
    • , Anna D. Engelke
    •  & Christopher Horst Lillig
  • Article
    | Open Access

    G-quadruplex (G4) forming sequences are highly enriched in the human genome and function as important regulators of diverse range of biological processes. Here the authors show that while G4 structures on template strand block transcription, folding on the non-template strand enhances transcription by means of successive R-loop formation.

    • Chun-Ying Lee
    • , Christina McNerney
    •  & Sua Myong
  • Article
    | Open Access

    In mammals, DNA methylation patterns are established by two de novo DNA methyltransferases, DNMT3A and DNMT3B. Here the authors report the crystal structures of DNMT3B in complex with both CpG and CpA DNA, providing insight into the substrate-recognition mechanism underpinning the divergent genomic methylation activities of DNMT3A and DNMT3B.

    • Linfeng Gao
    • , Max Emperle
    •  & Jikui Song
  • Article
    | Open Access

    Receptor-linked protein tyrosine phosphatases (RPTPs) usually contain an active membrane proximal domain and an inactive pseudophosphatase domain. Here, the authors characterize an RPTP with two pseudophosphatase domains, providing evidence that it may act as a decoy receptor for substrate sequestration.

    • Iain M. Hay
    • , Gareth W. Fearnley
    •  & Janet E. Deane
  • Article
    | Open Access

    Plasmodium falciparum IMP-specific 5′-nucleotidase 1 (PfISN1) is of interest as a potential malaria drug target. Here, the authors report that IMP is a substrate, and ATP an allosteric activator, of PfISN1 and present PfISN1 crystal structures in the ligand-free state and bound to either IMP or ATP.

    • Loïc Carrique
    • , Lionel Ballut
    •  & Nushin Aghajari
  • Article
    | Open Access

    SAMHD1 catalyses the hydrolysis of dNTPs into 2′-deoxynucleosides and triphosphate and is an important regulator of cellular dNTP homeostasis. Here, the authors provide insights into the catalytic mechanism of SAMHD1 by performing kinetic measurements and determining crystal structures of α-β-imido-dNTP inhibitor complexes, which reveal a bi-metallic iron-magnesium centre and catalytic hydroxyl molecule in the active site of the enzyme.

    • Elizabeth R. Morris
    • , Sarah J. Caswell
    •  & Ian A. Taylor
  • Article
    | Open Access

    Rad51 drives DNA strand exchange, the central reaction in recombinational DNA repair. Two sites of Rad51 are responsible for DNA binding, but the function of these sites has proven elusive. Here, the authors employ real-time assays to reveal catalytic roles for the two DNA binding sites of Rad51.

    • Kentaro Ito
    • , Yasuto Murayama
    •  & Hiroshi Iwasaki
  • Article
    | Open Access

    Hydroxyglutarate synthase (HglS) converts 2-oxoadipate to D-2- hydroxyglutarate during lysine catabolism in bacteria. Here the authors use structural and biochemical approaches to show that HglS acts via successive decarboxylation and intramolecular hydroxylation and that homologous enzymes catalyze the final step of lysine catabolism in plants.

    • Mitchell G. Thompson
    • , Jacquelyn M. Blake-Hedges
    •  & Jay D. Keasling
  • Article
    | Open Access

    Mutation of the C-terminal extension of 5′-aminolevulinate synthase 2 (ALAS2) is the molecular cause for X-linked protoporphyria, but the underlying mechanism is unclear. Based on crystal structures and MD simulations of ALAS2, the authors here show how the C-terminal extension regulates ALAS2 activity.

    • Henry J. Bailey
    • , Gustavo A. Bezerra
    •  & Wyatt W. Yue
  • Article
    | Open Access

    Self-sufficient cytochrome P450 monooxygenases, which contain all redox partners in a single polypeptide chain, are of interest for biotechnological applications. Here, the authors present the crystal structure of full-length Thermobispora bispora CYP116B46 and discuss the potential electron transfer pathway.

    • Lilan Zhang
    • , Zhenzhen Xie
    •  & Chun-Chi Chen
  • Article
    | Open Access

    The mechanism of PARP1-dependent poly-ADP-ribosylation in response to DNA damage is still under debate. Here, the authors use ATR-FTIR spectroscopy to provide time-resolved insights into the molecular details of this process under near physiological conditions.

    • Annika Krüger
    • , Alexander Bürkle
    •  & Aswin Mangerich
  • Article
    | Open Access

    Rhodobacter capsulatus NAD+ dependent formate dehydrogenase (RcFDH) is a molybdoenzyme that catalyses the reversible oxidation of formate to carbon dioxide, and is of interest for biotechnological applications. Here the authors present the cryo-EM structures of RcFDH as isolated from R. capsulatus and in the reduced state with bound NADH, and discuss the enzyme mechanism.

    • Christin Radon
    • , Gerd Mittelstädt
    •  & Petra Wendler