title: Structure of Mycobacterium thermoresistibile GlgE defines novel conformational states that contribute to the catalytic mechanism.
abstract: GlgE, an enzyme of the pathway that converts trehalose to α-glucans, is essential for Mycobacterium tuberculosis. Inhibition of GlgE, which transfers maltose from a maltose-1-phosphate donor to α-glucan/maltooligosaccharide chain acceptor, leads to a toxic accumulation of maltose-1-phosphate that culminates in cellular death. Here we describe the first high-resolution mycobacterial GlgE structure from Mycobacterium thermoresistibile at 1.96 Å. We show that the structure resembles that of M. tuberculosis and Streptomyces coelicolor GlgEs, reported before, with each protomer in the homodimer comprising five domains. However, in M. thermoresistibile GlgE we observe several conformational states of the S domain and provide evidence that its high flexibility is important for enzyme activity. The structures here reported shed further light on the interactions between the N-terminal domains and the catalytic domains of opposing chains and how they contribute to the catalytic reaction. Importantly this work identifies a useful surrogate system to aid the development of GlgE inhibitors against opportunistic and pathogenic mycobacteria.
authors.affiliation: Department of Biochemistry, University of Cambridge, Cambridge CB2 1GA, UK.|Molecular Mycobacteriology Group, CNC-Center for Neuroscience and Cell Biology, University of Coimbra, 3004-517 Coimbra, Portugal.
authors.forename: Vitor
authors.initials: V
authors.lastname: Mendes
authors.affiliation: Department of Biochemistry, University of Cambridge, Cambridge CB2 1GA, UK.
authors.forename: Michal
authors.initials: M
authors.lastname: Blaszczyk
authors.affiliation: Molecular Mycobacteriology Group, CNC-Center for Neuroscience and Cell Biology, University of Coimbra, 3004-517 Coimbra, Portugal.
authors.forename: Ana
authors.initials: A
authors.lastname: Maranha
authors.affiliation: Molecular Mycobacteriology Group, CNC-Center for Neuroscience and Cell Biology, University of Coimbra, 3004-517 Coimbra, Portugal.
authors.forename: Nuno
authors.initials: N
authors.lastname: Empadinhas
authors.affiliation: Department of Biochemistry, University of Cambridge, Cambridge CB2 1GA, UK.
authors.forename: Tom L
authors.initials: TL
authors.lastname: Blundell
mesh_terms: D001426:Bacterial Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D001665:Binding Sites; D002384:Catalysis; D020134:Catalytic Domain; D018360:Crystallography, X-Ray; D005964:Glucosyltransferases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D007700:Kinetics; D008320:Maltose / Q000378:metabolism; D008958:Models, Molecular; D009161:Mycobacterium / Q000201:enzymology* / Q000235:genetics; D010766:Phosphorylation; D011487:Protein Conformation; D054730:Protein Interaction Domains and Motifs; D013329:Structure-Activity Relationship; D013403:Sugar Phosphates / Q000737:chemistry / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; D013403:Sugar Phosphates; C080751:maltose 1-phosphate; D008320:Maltose; D005964:Glucosyltransferases; C436710:maltosyltransferase