Besra GS

References (12)

Title : Anti-tubercular derivatives of rhein require activation by the monoglyceride lipase Rv0183 - Abrahams_2020_Cell.Surf_6_100040
Author(s) : Abrahams KA , Hu W , Li G , Lu Y , Richardson EJ , Loman NJ , Huang H , Besra GS
Ref : Cell Surf , 6 :100040 , 2020
Abstract : The emergence and perseverance of drug resistant strains of Mycobacterium tuberculosis (Mtb) ensures that drug discovery efforts remain at the forefront of tuberculosis research. There are numerous different approaches that can be employed to lead to the discovery of anti-tubercular agents. In this work, we endeavored to optimize the anthraquinone chemical scaffold of a known drug, rhein, converting it from a compound with negligible activity against Mtb, to a series of compounds with potent activity. Two compounds exhibited low toxicity and good liver microsome stability and were further progressed in attempts to identify the biological target. Whole genome sequencing of resistant isolates revealed inactivating mutations in a monoglyceride lipase. Over-expression trials and an enzyme assay confirmed that the designed compounds are prodrugs, activated by the monoglyceride lipase. We propose that rhein is the active moiety of the novel compounds, which requires chemical modifications to enable access to the cell through the extensive cell wall structure. This work demonstrates that re-engineering of existing antimicrobial agents is a valid method in the development of new anti-tubercular compounds.
ESTHER : Abrahams_2020_Cell.Surf_6_100040
PubMedSearch : Abrahams_2020_Cell.Surf_6_100040
PubMedID: 32743152
Gene_locus related to this paper: myctu-rv0183

Title : Role for lysosomal phospholipase A2 in iNKT cell-mediated CD1d recognition - Paduraru_2013_Proc.Natl.Acad.Sci.U.S.A_110_5097
Author(s) : Paduraru C , Bezbradica JS , Kunte A , Kelly R , Shayman JA , Veerapen N , Cox LR , Besra GS , Cresswell P
Ref : Proc Natl Acad Sci U S A , 110 :5097 , 2013
Abstract : Invariant natural killer T (iNKT) cells recognize self lipid antigens presented by CD1d molecules. The nature of the self-antigens involved in the development and maturation of iNKT cells is poorly defined. Lysophospholipids are self-antigens presented by CD1d that are generated through the action of phospholipases A1 and A2. Lysosomal phospholipase A2 (LPLA2, group XV phospholipase A2) resides in the endocytic system, the main site where CD1d antigen acquisition occurs, suggesting that it could be particularly important in CD1d function. We find that Lpla2(-/-) mice show a decrease in iNKT cell numbers that is neither the result of a general effect on the development of lymphocyte populations nor of effects on CD1d expression. However, endogenous lipid antigen presentation by CD1d is reduced in the absence of LPLA2. Our data suggest that LPLA2 plays a role in the generation of CD1d complexes with thymic lipids required for the normal selection and maturation of iNKT cells.
ESTHER : Paduraru_2013_Proc.Natl.Acad.Sci.U.S.A_110_5097
PubMedSearch : Paduraru_2013_Proc.Natl.Acad.Sci.U.S.A_110_5097
PubMedID: 23493550

Title : Functional role of the PE domain and immunogenicity of the Mycobacterium tuberculosis triacylglycerol hydrolase LipY - Mishra_2008_Infect.Immun_76_127
Author(s) : Mishra KC , de Chastellier C , Narayana Y , Bifani P , Brown AK , Besra GS , Katoch VM , Joshi B , Balaji KN , Kremer L
Ref : Infect Immun , 76 :127 , 2008
Abstract : PE and PPE proteins appear to be important for virulence and immunopathogenicity in mycobacteria, yet the functions of the PE/PPE domains remain an enigma. To decipher the role of these domains, we have characterized the triacylglycerol (TAG) hydrolase LipY from Mycobacterium tuberculosis, which is the only known PE protein expressing an enzymatic activity. The overproduction of LipY in mycobacteria resulted in a significant reduction in the pool of TAGs, consistent with the lipase activity of this enzyme. Unexpectedly, this reduction was more pronounced in mycobacteria overexpressing LipY lacking the PE domain [LipY(deltaPE)], suggesting that the PE domain participates in the modulation of LipY activity. Interestingly, Mycobacterium marinum contains a protein homologous to LipY, termed LipY(mar), in which the PE domain is substituted by a PPE domain. As for LipY, overexpression of LipY(mar) in Mycobacterium smegmatis significantly reduced the TAG pool, and this was further pronounced when the PPE domain of LipY(mar) was removed. Fractionation studies and Western blot analysis demonstrated that both LipY and LipY(deltaPE) were mainly present in the cell wall, indicating that the PE domain was not required for translocation to this site. Furthermore, electron microscopy immunolabeling of LipY(deltaPE) clearly showed a cell surface localization, thereby suggesting that the lipase may interact with the host immune system. Accordingly, a strong humoral response against LipY and LipY(deltaPE) was observed in tuberculosis patients. Together, our results suggest for the first time that both PE and PPE domains can share similar functional roles and that LipY represents a novel immunodominant antigen.
ESTHER : Mishra_2008_Infect.Immun_76_127
PubMedSearch : Mishra_2008_Infect.Immun_76_127
PubMedID: 17938218
Gene_locus related to this paper: myctu-Rv3097c

Title : A highly conserved transcriptional repressor controls a large regulon involved in lipid degradation in Mycobacterium smegmatis and Mycobacterium tuberculosis - Kendall_2007_Mol.Microbiol_65_684
Author(s) : Kendall SL , Withers M , Soffair CN , Moreland NJ , Gurcha S , Sidders B , Frita R , Ten Bokum A , Besra GS , Lott JS , Stoker NG
Ref : Molecular Microbiology , 65 :684 , 2007
Abstract : The Mycobacterium tuberculosis TetR-type regulator Rv3574 has been implicated in pathogenesis as it is induced in vivo, and genome-wide essentiality studies show it is required for infection. As the gene is highly conserved in the mycobacteria, we deleted the Rv3574 orthologue in Mycobacterium smegmatis (MSMEG_6042) and used real-time quantitative polymerase chain reaction and microarray analyses to show that it represses the transcription both of itself and of a large number of genes involved in lipid metabolism. We identified a conserved motif within its own promoter (TnnAACnnGTTnnA) and showed that it binds as a dimer to 29 bp probes containing the motif. We found 16 and 31 other instances of the motif in intergenic regions of M. tuberculosis and M. smegmatis respectively. Combining the results of the microarray studies with the motif analyses, we predict that Rv3574 directly controls the expression of 83 genes in M. smegmatis, and 74 in M. tuberculosis. Many of these genes are known to be induced by growth on cholesterol in rhodococci, and palmitate in M. tuberculosis. We conclude that this regulator, designated elsewhere as kstR, controls the expression of genes used for utilizing diverse lipids as energy sources, possibly imported through the mce4 system.
ESTHER : Kendall_2007_Mol.Microbiol_65_684
PubMedSearch : Kendall_2007_Mol.Microbiol_65_684
PubMedID: 17635188
Gene_locus related to this paper: myctu-Rv3569c

Title : Inactivation of polyketide synthase and related genes results in the loss of complex lipids in Mycobacterium tuberculosis H37Rv - Waddell_2005_Lett.Appl.Microbiol_40_201
Author(s) : Waddell SJ , Chung GA , Gibson KJ , Everett MJ , Minnikin DE , Besra GS , Butcher PD
Ref : Lett Appl Microbiol , 40 :201 , 2005
Abstract : AIMS: Phthiocerol dimycocerosate (PDIM) waxes and other lipids are necessary for successful Mycobacterium tuberculosis infection, although the exact role of PDIM in host-pathogen interactions remains unclear. In this study, we investigated the contribution of tesA, drrB, pks6 and pks11 genes in complex lipid biosynthesis in M. tuberculosis. METHODS AND RESULTS: Four mutants were selected from M. tuberculosis H37Rv transposon mutant library. The transposon insertion sites were confirmed to be within the M. tuberculosis open reading frames for tesA (a probable thioesterase), drrB (predicted ABC transporter), pks11 (putative chalcone synthase) and pks6 (polyketide synthase). The first three of these transposon mutants were unable to generate PDIM and the fourth lacked novel polar lipids. CONCLUSIONS: Mycobacterium tuberculosis can be cultivated in vitro without the involvement of certain lipid synthesis genes, which may be necessary for in vivo pathogenicity. SIGNIFICANCE AND IMPACT OF THE STUDY: The use of transposon mutants is a new functional genomic approach for the eventual definition of the mycobacterial 'lipidome'.
ESTHER : Waddell_2005_Lett.Appl.Microbiol_40_201
PubMedSearch : Waddell_2005_Lett.Appl.Microbiol_40_201
PubMedID: 15715645
Gene_locus related to this paper: myctu-yt28

Title : Mycobacterium tuberculosis antigen 85A and 85C structures confirm binding orientation and conserved substrate specificity - Ronning_2004_J.Biol.Chem_279_36771
Author(s) : Ronning DR , Vissa V , Besra GS , Belisle JT , Sacchettini JC
Ref : Journal of Biological Chemistry , 279 :36771 , 2004
Abstract : The maintenance of the highly hydrophobic cell wall is central to the survival of Mycobacterium tuberculosis within its host environment. The antigen 85 proteins (85A, 85B, and 85C) of M. tuberculosis help maintain the integrity of the cell wall 1) by catalyzing the transfer of mycolic acids to the cell wall arabinogalactan and 2) through the synthesis of trehalose dimycolate (cord factor). Additionally, these secreted proteins allow for rapid invasion of alveolar macrophages via direct interactions between the host immune system and the invading bacillus. Here we describe two crystal structures: the structure of antigen 85C co-crystallized with octylthioglucoside as substrate, resolved to 2.0 A, and the crystal structure of antigen 85A, which was solved at a resolution of 2.7 A. The structure of 85C with the substrate analog identifies residues directly involved in substrate binding. Elucidation of the antigen 85A structure, the last of the three antigen 85 homologs to be solved, shows that the active sites of the three antigen 85 proteins are virtually identical, indicating that these share the same substrate. However, in contrast to the high level of conservation within the substrate-binding site and the active site, surface residues disparate from the active site are quite variable, indicating that three antigen 85 enzymes are needed to evade the host immune system.
ESTHER : Ronning_2004_J.Biol.Chem_279_36771
PubMedSearch : Ronning_2004_J.Biol.Chem_279_36771
PubMedID: 15192106
Gene_locus related to this paper: myctu-a85a , myctu-a85c

Title : Phosphonate inhibitors of antigen 85C, a crucial enzyme involved in the biosynthesis of the Mycobacterium tuberculosis cell wall - Gobec_2004_Bioorg.Med.Chem.Lett_14_3559
Author(s) : Gobec S , Plantan I , Mravljak J , Wilson RA , Besra GS , Kikelj D
Ref : Bioorganic & Medicinal Chemistry Lett , 14 :3559 , 2004
Abstract : The first phosphonate inhibitors of antigen 85C--a major protein component of the Mycobacterium tuberculosis cell wall possessing mycolyltransferase activity were prepared using structure-based design. These potential novel antituberculosis agents, consisting of a phosphonate moiety, hydrophobic alkyl chain and a simple trehalose-mimicking aromatic structure, were designed as tetrahedral transition-state analogue inhibitors of antigen 85C, which catalyzes the key mycolyltransferase reaction involved in cell wall biosynthesis.
ESTHER : Gobec_2004_Bioorg.Med.Chem.Lett_14_3559
PubMedSearch : Gobec_2004_Bioorg.Med.Chem.Lett_14_3559
PubMedID: 15177473

Title : The structure of Mycobacterium tuberculosis MPT51 (FbpC1) defines a new family of non-catalytic alpha\/beta hydrolases - Wilson_2004_J.Mol.Biol_335_519
Author(s) : Wilson RA , Maughan WN , Kremer L , Besra GS , Futterer K
Ref : Journal of Molecular Biology , 335 :519 , 2004
Abstract : Mycobacterium tuberculosis, the causative agent of tuberculosis, is known to secrete a number of highly immunogenic proteins that are thought to confer pathogenicity, in part, by mediating binding to host tissues. Among these secreted proteins are the trimeric antigen 85 (Ag85) complex and the related MPT51 protein, also known as FbpC1. While the physiological function of Ag85, a mycolyltransferase required for the biosynthesis of the cell wall component alpha,alpha'-trehalose dimycolate (or cord factor), has been identified recently, the function of the closely related MPT51 (approximately 40% identity with the Ag85 components) remains to be established. The crystal structure of M.tuberculosis MPT51, determined to 1.7 A resolution, shows that MPT51, like the Ag85 components Ag85B and Ag85C2, folds as an alpha/beta hydrolase, but it does not contain any of the catalytic elements required for mycolyltransferase activity. Moreover, the absence of a recognizable alpha,alpha'-trehalose monomycolate-binding site and the failure to detect an active site suggest that the function of MPT51 is of a non-enzymatic nature and that MPT51 may in fact represent a new family of non-catalytic alpha/beta hydrolases. Previous experimental evidence and the structural similarity to some integrins and carbohydrate-binding proteins led to the hypothesis that MPT51 might have a role in host tissue attachment, whereby ligands may include the serum protein fibronectin and small sugars.
ESTHER : Wilson_2004_J.Mol.Biol_335_519
PubMedSearch : Wilson_2004_J.Mol.Biol_335_519
PubMedID: 14672660
Gene_locus related to this paper: myctu-mpt51

Title : Sequencing and analysis of the genome of the Whipple's disease bacterium Tropheryma whipplei - Bentley_2003_Lancet_361_637
Author(s) : Bentley SD , Maiwald M , Murphy LD , Pallen MJ , Yeats CA , Dover LG , Norbertczak HT , Besra GS , Quail MA , Harris DE , von Herbay A , Goble A , Rutter S , Squares R , Squares S , Barrell BG , Parkhill J , Relman DA
Ref : Lancet , 361 :637 , 2003
Abstract : BACKGROUND: Whipple's disease is a rare multisystem chronic infection, involving the intestinal tract as well as various other organs. The causative agent, Tropheryma whipplei, is a Gram-positive bacterium about which little is known. Our aim was to investigate the biology of this organism by generating and analysing the complete DNA sequence of its genome. METHODS: We isolated and propagated T whipplei strain TW08/27 from the cerebrospinal fluid of a patient diagnosed with Whipple's disease. We generated the complete sequence of the genome by the whole genome shotgun method, and analysed it with a combination of automatic and manual bioinformatic techniques. FINDINGS: Sequencing revealed a condensed 925938 bp genome with a lack of key biosynthetic pathways and a reduced capacity for energy metabolism. A family of large surface proteins was identified, some associated with large amounts of non-coding repetitive DNA, and an unexpected degree of sequence variation. INTERPRETATION: The genome reduction and lack of metabolic capabilities point to a host-restricted lifestyle for the organism. The sequence variation indicates both known and novel mechanisms for the elaboration and variation of surface structures, and suggests that immune evasion and host interaction play an important part in the lifestyle of this persistent bacterial pathogen.
ESTHER : Bentley_2003_Lancet_361_637
PubMedSearch : Bentley_2003_Lancet_361_637
PubMedID: 12606174
Gene_locus related to this paper: trowh-TW083.1 , trowh-TW083.2 , trowh-TWT693

Title : The complete genome sequence and analysis of Corynebacterium diphtheriae NCTC13129 - Cerdeno-Tarraga_2003_Nucleic.Acids.Res_31_6516
Author(s) : Cerdeno-Tarraga AM , Efstratiou A , Dover LG , Holden MT , Pallen M , Bentley SD , Besra GS , Churcher C , James KD , De Zoysa A , Chillingworth T , Cronin A , Dowd L , Feltwell T , Hamlin N , Holroyd S , Jagels K , Moule S , Quail MA , Rabbinowitsch E , Rutherford KM , Thomson NR , Unwin L , Whitehead S , Barrell BG , Parkhill J
Ref : Nucleic Acids Research , 31 :6516 , 2003
Abstract : Corynebacterium diphtheriae is a Gram-positive, non-spore forming, non-motile, pleomorphic rod belonging to the genus Corynebacterium and the actinomycete group of organisms. The organism produces a potent bacteriophage-encoded protein exotoxin, diphtheria toxin (DT), which causes the symptoms of diphtheria. This potentially fatal infectious disease is controlled in many developed countries by an effective immunisation programme. However, the disease has made a dramatic return in recent years, in particular within the Eastern European region. The largest, and still on-going, outbreak since the advent of mass immunisation started within Russia and the newly independent states of the former Soviet Union in the 1990s. We have sequenced the genome of a UK clinical isolate (biotype gravis strain NCTC13129), representative of the clone responsible for this outbreak. The genome consists of a single circular chromosome of 2 488 635 bp, with no plasmids. It provides evidence that recent acquisition of pathogenicity factors goes beyond the toxin itself, and includes iron-uptake systems, adhesins and fimbrial proteins. This is in contrast to Corynebacterium's nearest sequenced pathogenic relative, Mycobacterium tuberculosis, where there is little evidence of recent horizontal DNA acquisition. The genome itself shows an unusually extreme large-scale compositional bias, being noticeably higher in G+C near the origin than at the terminus.
ESTHER : Cerdeno-Tarraga_2003_Nucleic.Acids.Res_31_6516
PubMedSearch : Cerdeno-Tarraga_2003_Nucleic.Acids.Res_31_6516
PubMedID: 14602910
Gene_locus related to this paper: cordi-DIP1007 , cordi-DIP1729 , cordi-q6ned6 , cordi-q6nes3 , cordi-q6nes4 , cordi-q6nes6 , cordi-q6nes8 , cordi-q6nev5 , cordi-q6nex0 , cordi-q6nez6 , cordi-q6nf79 , cordi-q6nfa8 , cordi-q6nfg5 , cordi-q6nfz1 , cordi-q6ng42 , cordi-q6ngl8 , cordi-q6nhd8 , cordi-q6niz3 , cordi-q6nj46 , cordi-q6njn3 , cordi-q6njn4 , cordi-q6njt5 , cordi-q6nkb6 , cordk-h2hkn5

Title : Crystal structure of the secreted form of antigen 85C reveals potential targets for mycobacterial drugs and vaccines - Ronning_2000_Nat.Struct.Biol_7_141
Author(s) : Ronning DR , Klabunde T , Besra GS , Vissa VD , Belisle JT , Sacchettini JC
Ref : Nat Struct Biol , 7 :141 , 2000
Abstract : The antigen 85 (ag85) complex, composed of three proteins (ag85A, B and C), is a major protein component of the Mycobacterium tuberculosis cell wall. Each protein possesses a mycolyltransferase activity required for the biogenesis of trehalose dimycolate (cord factor), a dominant structure necessary for maintaining cell wall integrity. The crystal structure of recombinant ag85C from M. tuberculosis, refined to a resolution of 1.5 A, reveals an alpha/beta-hydrolase polypeptide fold, and a catalytic triad formed by Ser 124, Glu 228 and His 260. ag85C complexed with a covalent inhibitor implicates residues Leu 40 and Met 125 as components of the oxyanion hole. A hydrophobic pocket and tunnel extending 21 A into the core of the protein indicates the location of a probable trehalose monomycolate binding site. Also, a large region of conserved surface residues among ag85A, B and C is a probable site for the interaction of ag85 proteins with human fibronectin.
ESTHER : Ronning_2000_Nat.Struct.Biol_7_141
PubMedSearch : Ronning_2000_Nat.Struct.Biol_7_141
PubMedID: 10655617
Gene_locus related to this paper: myctu-a85c

Title : Role of the major antigen of Mycobacterium tuberculosis in cell wall biogenesis - Belisle_1997_Science_276_1420
Author(s) : Belisle JT , Vissa VD , Sievert T , Takayama K , Brennan PJ , Besra GS
Ref : Science , 276 :1420 , 1997
Abstract : The dominant exported proteins and protective antigens of Mycobacterium tuberculosis are a triad of related gene products called the antigen 85 (Ag85) complex. Each has also been implicated in disease pathogenesis through its fibronectin-binding capacities. A carboxylesterase domain was found within the amino acid sequences of Ag85A, B, and C, and each protein acted as a mycolyltransferase involved in the final stages of mycobacterial cell wall assembly, as shown by direct enzyme assay and site-directed mutagenesis. Furthermore, the use of an antagonist (6-azido-6-deoxy-alpha, alpha'-trehalose) of this activity demonstrates that these proteins are essential and potential targets for new antimycobacterial drugs.
ESTHER : Belisle_1997_Science_276_1420
PubMedSearch : Belisle_1997_Science_276_1420
PubMedID: 9162010
Gene_locus related to this paper: myctu-a85a , myctu-a85b , myctu-a85c