Multienzyme complexes

  • Article
    | Open Access

    AGPATs (1-acylglycerol-3-phosphate O-acyltransferases) catalyze the acylation of lysophosphatidic acid to form phosphatidic acid (PA), a key step in the synthesis of all glycerolipids. Here, the authors show that AGPAT2 and CDP-DAG synthases (CDS1 and CDS2) form functional complexes that promote further conversion of PA along the CDP-DAG pathway of phospholipid synthesis.

    • Hoi Yin Mak
    • , Qian Ouyang
    •  & Hongyuan Yang
  • Article
    | Open Access

    Engineering biosynthetic assembly lines is a powerful path to new natural products but is challenging with current methods. Here the authors use CRISPR-Cas9 to exchange subdomains within NRPS to alter substrate selectivity.

    • Wei Li Thong
    • , Yingxin Zhang
    •  & Jason Micklefield
  • Article
    | Open Access

    The E3 ligase Hakai can interact with the m6A methylation machinery but its function is still unclear. Here, the authors show that Hakai is a conserved component of the m6A methyltransferase complex and provide functional and molecular insights into its role in regulating m6A levels in Drosophila.

    • Praveen Bawankar
    • , Tina Lence
    •  & Jean-Yves Roignant
  • Article
    | Open Access

    Substrate channeling can improve biosynthetic efficiency and has been implicated in the reactions of fusicoccadiene synthase. Here, the authors analyze this bifunctional enzyme complex by cryoEM, cross-linking MS and integrative modeling, providing structural insights into how substrate channeling is achieved.

    • Jacque L. Faylo
    • , Trevor van Eeuwen
    •  & David W. Christianson
  • Article
    | Open Access

    The SARS-CoV-2 nsp16/nsp10 enzyme complex methylates the 2′-OH of the first nucleotide of the viral mRNA, converting the Cap-0 to Cap-1, which helps the virus to evade immune surveillance in the host cell. Here, the authors present the crystal structure of SARS-CoV-2 nsp16/nsp10 with the bound Cap-1 RNA nucleotide product and a post-release SAH containing structure.

    • Thiruselvam Viswanathan
    • , Anurag Misra
    •  & Yogesh K. Gupta
  • Article
    | Open Access

    In some systems, a single protein comprising reverse transcriptase (RT), integrase and maturase enables concerted sequence integration and crRNA production. Here, analyses including the structure of a Cas6-RT-Cas1—Cas2 complex suggest coordination between all three active sites and capacity to acquire CRISPR sequences from RNA and DNA substrates.

    • Joy Y. Wang
    • , Christopher M. Hoel
    •  & Jennifer A. Doudna
  • Article
    | Open Access

    Non-ribosomal peptide synthetases (NRPSs) are multi-modular enzymes assembling complex natural products. Here, the structures of a Thermobifida fusca NRPS condensation domain bound to the substrate-bearing peptidyl carrier protein (PCP) domain provide insight into the mechanisms of substrate selectivity and engagement within the catalytic pocket.

    • Thierry Izoré
    • , Y. T. Candace Ho
    •  & Max J. Cryle
  • Article
    | Open Access

    Respiratory chains generate the proton motive force used for ATP synthesis. Cryo-EM structures of functional respiratory CIII2CIV supercomplex and native CIII2 from Rhodobacter capsulatus provide insight into CIII2CIV assembly and respiratory electron transport pathways in Gram-negative bacteria.

    • Stefan Steimle
    • , Trevor van Eeuwen
    •  & Fevzi Daldal
  • Article
    | Open Access

    Biosynthesis of the statin precursor lovastatin depends on the LovB–LovC megasynthase complex. Here, the authors present cryoEM structures of LovB–LovC and core LovB, providing structural insights into the catalytic cycle underlying lovastatin production.

    • Jialiang Wang
    • , Jingdan Liang
    •  & Zhijun Wang
  • Article
    | Open Access

    Pyruvate kinase phosphorylates histone H3T11 (H3pT11) and represses gene expression by forming a large complex SESAME (Serine-responsive SAM-containing Metabolic Enzyme). Here the authors show that SESAME-catalyzed H3pT11 regulates telomere silencing by promoting Sir2 binding at telomeres and preventing autophagy-mediated Sir2 degradation.

    • Shihao Zhang
    • , Xilan Yu
    •  & Shanshan Li
  • Article
    | Open Access

    Lipopolysaccharides, important components of the bacterial cell envelope, are synthesized at the inner membrane by the Wzx/Wzy-dependent assembly pathway. A cryo-EM structure of an intact E. coli WzzB, the polysaccharide co-polymerase component of this pathway, reveals details of the transmembrane, cytoplasmic domains and a conserved a proline-rich segment proximal to the C-terminal transmembrane helix.

    • Benjamin Wiseman
    • , Ram Gopal Nitharwal
    •  & Martin Högbom
  • Article
    | Open Access

    Non-ribosomal peptide synthases are multimodular enzymes comprised of adenylation (A), condensation (C) and thiolation domains. Here, the authors show that non-ribosomal peptides can be generated solely by A domain substitutions, providing evidence that the postulated substrate specifying role of C-domains may be rare in nature.

    • Mark J. Calcott
    • , Jeremy G. Owen
    •  & David F. Ackerley
  • Article
    | Open Access

    Peroxiredoxin 2 (Prx2) was previously shown to transfer H2O2-derived oxidative equivalents to STAT3, generating disulfide-linked dimers and tetramers. Here the authors show that the interaction between Prx2 and STAT3 at the plasma membrane is mediated by the membrane chaperone annexin A2; suggesting that the redox relay complex is part of a membrane signaling domain.

    • Deepti Talwar
    • , Joris Messens
    •  & Tobias P. Dick
  • Article
    | Open Access

    The formation of C-C bonds in fatty acid and polyketide biosynthesis depends on β-ketoacyl-acyl carrier protein (ACP) synthases (KSs). Here, the authors present structures of E.coli KSs bound to substrate mimetic bearing ACPs, providing insights into the catalytic mechanism underlying C-C bond forming reactions.

    • Jeffrey T. Mindrebo
    • , Ashay Patel
    •  & Michael D. Burkart
  • Article
    | Open Access

    Mfd recognizes stalled transcriptional complexes at sites of lesions and recruits the nucleotide excision repair proteins (UvrAB) to the site. Here the authors use live cell imaging in E. coli to demonstrate that coordinated ATP hydrolysis by UvrA and loading of UvrB on DNA facilitate the dissociation of Mfd from the handoff complex.

    • Han Ngoc Ho
    • , Antoine M. van Oijen
    •  & Harshad Ghodke
  • Article
    | Open Access

    Respiratory syncytial virus (RSV) is a pathogenic non-segmented negative-sense RNA virus and active RSV polymerase is composed of a 250 kDa large (L) protein and tetrameric phosphoprotein (P). Here, the authors present the 3.67 Å cryo-EM structure of the RSV polymerase (L:P) complex.

    • Dongdong Cao
    • , Yunrong Gao
    •  & Bo Liang
  • Article
    | Open Access

    A robust platform to study modular polyketide synthases (PKSs) in vitro is still unavailable. Here, the authors report the reconstitution of the venemycin PKS, engineer hybrid venemycin/pikromycin PKSs, and obtain much improved yields through employing the updated module boundaries.

    • Takeshi Miyazawa
    • , Melissa Hirsch
    •  & Adrian T. Keatinge-Clay
  • Article
    | Open Access

    The bacterial enzyme PaaZ is involved in the breakdown of environmental pollutants via the aerobic-anaerobic hybrid pathway but its substrate transfer mechanism is not fully understood. Here, the authors present cryoEM structures of free and ligand-bound PaaZ that suggest a mechanism for internal substrate channeling.

    • Nitish Sathyanarayanan
    • , Giuseppe Cannone
    •  & Kutti R. Vinothkumar
  • Article
    | Open Access

    The mechanism of iron-sulfur (Fe-S) cluster biosynthesis is not fully understood. Here, the authors develop a physiologically relevant in vitro model of Fe-S cluster assembly, allowing them to elucidate the sequence of Fe-S cluster synthesis along with the respective roles of ferredoxin-2 and frataxin.

    • Sylvain Gervason
    • , Djabir Larkem
    •  & Benoit D’Autréaux
  • Article
    | Open Access

    The cell wall of Gram-positive bacteria consists of peptidoglycan modified with other polymers, such as the capsular polysaccharide. Here, the authors reconstitute the biosynthesis of capsular polysaccharide and elucidate its interplay with the cell wall biosynthetic machinery.

    • Marvin Rausch
    • , Julia P. Deisinger
    •  & Tanja Schneider
  • Article
    | Open Access

    Mitochondrial protein synthesis requires charging a mitochondrial tRNA with its amino acid. Here, the authors describe pathogenic variants in the GatCAB protein complex genes required for the generation of glutaminyl-mt-tRNAGln, that impairs mitochondrial translation and presents with cardiomyopathy.

    • Marisa W. Friederich
    • , Sharita Timal
    •  & Johan L. K. Van Hove
  • Article
    | Open Access

    Modifying the non-ribosomal peptide synthase (NRPS)/polyketide synthase (PKS) pathway to generate novel non-ribosomal peptides often results in a loss of productivity. Here the authors use evolutionary alignments of NRPS/PKS gene clusters to guide rational design of complexes that can produce novel lactones.

    • Takayoshi Awakawa
    • , Takuma Fujioka
    •  & Ikuro Abe
  • Article
    | Open Access

    Catabolizing lignin-derived aromatic compounds requires an aryl-O-demethylation step. Here the authors present the structures of GcoA and GcoB, a cytochrome P450-reductase pair that catalyzes aryl-O-demethylations and show that GcoA displays broad substrate specificity, which is of interest for biotechnology applications.

    • Sam J. B. Mallinson
    • , Melodie M. Machovina
    •  & John E. McGeehan
  • Review Article
    | Open Access

    Temporary association of metabolic enzymes is generally assumed to facilitate substrate channelling within the complex. In this review, Lee Sweetlove and Alisdair Fernie outline the nature and functional consequence of organising enzymes into assemblies, and discuss applications within the natural world and synthetic biology.

    • Lee J. Sweetlove
    •  & Alisdair R. Fernie
  • Article
    | Open Access

    Carrier domain enzymes accomplish catalysis by physically transporting intermediates long distances between remote active sites. Here the authors describe a wide range of catalytically productive translocation events during catalysis by pyruvate carboxylase and suggest a basis for its allosteric activation.

    • Yumeng Liu
    • , Melissa M. Budelier
    •  & Martin St. Maurice
  • Article
    | Open Access

    The mitochondrial RNA degradosome (mtEXO) plays an essential role in the regulation of mitochondrial gene expression and is composed of the 3′-to-5′ exoribonuclease Dss1 and the helicase Suv3. Here the authors present the RNA bound mtEXO crystal structure and give insights into its mechanism.

    • Michal Razew
    • , Zbigniew Warkocki
    •  & Marcin Nowotny
  • Article
    | Open Access

    Alteration of the epigenetic landscape has been implicated in several disease processes, where targeting histone modifiers may have therapeutic applications. Here the authors report a bifunctional small molecule inhibitor that simultaneously targets the deacetylase (HDAC1) and demethylase (LSD1) activities of the CoREST complex.

    • Jay H. Kalin
    • , Muzhou Wu
    •  & Philip A. Cole
  • Article
    | Open Access

    Metalloproteinase inhibitors are leads for drug development, but their biosynthetic pathways are often unknown. Here the authors show that the acyl branched warhead of actinonin and matlystatins derives from an ethylmalonyl-CoA-like pathway and the structural diversity of matlystatins is due to the activity of a decarboxylase-dehydrogenase enzyme.

    • Franziska Leipoldt
    • , Javier Santos-Aberturas
    •  & Leonard Kaysser
  • Article
    | Open Access

    Nonribosomal peptides are important bioactive molecules that are synthetized by enzymes containing several catalytic domains. Here the authors describe the catalytic mechanism of fungal nonribosomal peptide synthetases and present an approach to modify these enzymes to produce specific nonribosomal peptides.

    • Dayu Yu
    • , Fuchao Xu
    •  & Jixun Zhan
  • Article
    | Open Access

    A metabolon is a complex of sequential metabolic enzymes that channels substrates directly between enzymes, thus optimizing metabolic flux. Here Zhanget al. provide protein interaction and isotope dilution data that support the existence of a metabolon that channels both citrate and fumarate in the plant TCA cycle.

    • Youjun Zhang
    • , Katherine F. M. Beard
    •  & Toshihiro Obata
  • Article
    | Open Access

    Polyketides are typically assembled from a starter unit and malonyl- and/or methylmalonyl-CoA-derived extender units, but the macrolide antibiotics stambomycins incorporate non-standard alkylmalonyl-CoA extender units. Here, the authors describe the biosynthetic pathway responsible for this unusual synthesis.

    • Lauren Ray
    • , Timothy R. Valentic
    •  & Gregory L. Challis
  • Article
    | Open Access

    Pyruvate carboxylases are homotetrameric enzymes in eukaryotes and most bacteria. Here, the authors report the structure of an unusual two-subunit form of the enzyme from the Gram-negative bacterium Methylobacillus flagellates, revealing an unexpected α2β4stoichiometry.

    • Philip H. Choi
    • , Jeanyoung Jo
    •  & Liang Tong