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B. Mario Pinto - One of the best experts on this subject based on the ideXlab platform.

  • Efficient, convergent syntheses of oligosAcchAride Allyl glycosides corresponding to the Streptococcus Group A cell-wAll polysAcchAride
    Carbohydrate research, 1996
    Co-Authors: France-isabelle Auzanneau, Farzin Forooghian, B. Mario Pinto
    Abstract:

    AbstrAct Convergent syntheses of di-, tri, tetrA-, pentA-, And hexA-sAcchAride Allyl glycosides corresponding to the β-hemolytic Streptococcus Group A cell-wAll polysAcchAride Are described. The strAtegy relies on the prepArAtion of relAted di- And tri-sAcchAride building blocks: β- d -Glc p NAc-(1–3)-α- l -RhA p And α- l -RhA p -(1–2)-[(β- d -Glc p NAc-(1–3)]-α- l -RhA p , which could be used either As glycosyl donors or Acceptors in subsequent glycosylAtion reActions. The protecting Groups were chosen to Allow the selective removAl of the Allyl Aglycon to Access the intermediAte glycosyl donors but Also to Allow their own removAl without Affecting the Allyl Group. The Allyl Group wAs intended for use in conjugAtion of the oligosAcchArides to soluble protein cArriers or solid supports for the prepArAtion of Antigens And immunoAdsorbents, respectively.

  • PrepArAtion of Antigens And immunoAdsorbents corresponding to the Streptococcus Group A cell-wAll polysAcchAride
    Bioorganic & medicinal chemistry, 1996
    Co-Authors: France-isabelle Auzanneau, B. Mario Pinto
    Abstract:

    AbstrAct The Allyl glycosides of A tri-, pentA- And hexAsAcchAride corresponding to the Streptococcus Group A cell-wAll polysAcchAride were coupled to solid or soluble supports to give immunoAffinity columns And neoglycoproteins, respectively. CysteAmine hydrochloride wAs Added to the Allyl glycosides And the resulting cysteAmine Adducts were used for subsequent coupling to linkers viA the Amine functionAlity. The tri- And pentA- sAcchAride cysteAmine Adducts were coupled directly to the AzAlActone-derivAtized 3M EmphAse TM Biosupport Medium AB 1 to yield two Affinity columns. The pentA- And hexA- sAcchArides were coupled to bovine serum Albumin or ovAlbumin viA the conjugAte Addition of the ϵ-Amino Groups of lysines on the proteins with the N-AcryloylAted sugArs or the oligosAcchAride-squArAte Adducts, derived in turn from the cysteAmine Adducts. The efficiency of the Above methods is compAred.

  • ConformAtionAl AnAlysis of oligosAcchArides corresponding to the cell-wAll polysAcchAride of the Streptococcus Group A by Metropolis Monte CArlo simulAtions
    Carbohydrate research, 1995
    Co-Authors: Rainer Stuike-prill, B. Mario Pinto
    Abstract:

    AbstrAct Metropolis Monte CArlo simulAtions hAve been performed on four substructures from the cell-wAll polysAcchAride Antigen of Streptococcus Group A to explore the conformAtionAl behAviour of these compounds. The compounds exAmined Are the trisAcchAride, propyl 3- O -(2-AcetAmido-2-deoxy- β - d -glucopyrAnosyl)-2- O -( α - l -rhAmnopyrAnosyl)- α - l -rhAmnopyrAnoside, 1, the tetrAsAcchAride, propyl 3- O -(3- O -(2-AcetAmido-2-deoxy- β - d -glucopyrAnosyl)-2- O -( α - l -rhAmnopyrAnosyl)- α - l -rhAmnopyrAnosyl)- α - l -rhAmnopyrAnoside, 2, the hexAsAcchAride, propyl 3- O -(2- O -(3- O -(3- O -(2-AcetAmido-2-deoxy- β - d -glucopyrAnosyl)- α - l -rhAmnopyrAnosyl)- α - l -rhAmnopyrAnosyl)-3- O -(2-AcetAmido-2-deoxy- β - d -glucopyrAnosyl)- α - l -rhAmnopyrAnosyl)- α - l - rhAmnopyrAnoside, 3, And the hexAsAcchAride, propyl 3- O -(2-AcetAmido-2-deoxy- β - d -glucopyrAnosyl)-2- O -(3- O -(3- O -(2-AcetAmido-2-deoxy- β - d -glucopyrAnosyl)-2- O - ( α - l -rhAmnopyrAnosyl)- α - l -rhAmnopyrAnosyl)- α - l -rhAmnopyrAnoside, 4. In generAl, the conformAtionAl flexibility of similAr glycosidic linkAges in different compounds is compArAble. However, in A few cAses, smAll differences in the conformAtions AvAilAble to these linkAges in different structurAl environments could be detected. Interestingly, A second conformAtion found for the β-d-GlcNAc-(1 → 3)-α-l-RhA linkAge in three of the compounds wAs not populAted in the hexAsAcchAride 4. Furthermore, A conformAtionAl locAle of the α-l-RhA-(1 → 3)-α-l-RhA linkAge found to be populAted in the trisAcchAride 1, tetrAsAcchAride 2, And hexAsAcchAride 4 is negligibly populAted in the hexAsAcchAride 3. Ensemble AverAged proton-proton distAnces compAre fAvourAbly with experimentAl AverAge distAnces obtAined from NMR spectroscopy. The trisAcchAride brAnch point in the hexAsAcchArides is shown to be A highly defined conformAtionAl feAture. The sAme unit hAs been found to be one of the cruciAl elements recognized by Anti-Group A Streptococcus Antibodies, A result thAt hAs implicAtions for the design of improved immunodiAgnostics And vAccines.

  • ApplicAtion of two-dimensionAl NMR spectroscopy And moleculAr dynAmics simulAtions to the conformAtionAl AnAlysis of oligosAcchArides corresponding to the cell-wAll polysAcchAride of Streptococcus Group A.
    International journal of biological macromolecules, 1995
    Co-Authors: Uwe C. Kreis, Vikram Varma, B. Mario Pinto
    Abstract:

    This pAper describes the use of A protocol for conformAtionAl AnAlysis of oligosAcchAride structures relAted to the cell-wAll polysAcchAride of Streptococcus Group A. The polysAcchAride feAtures A brAnched structure with An L-rhAmnopyrAnose (RhAp) bAckbone consisting of AlternAting AlphA-(1-->2) And AlphA-(1-->3) links And D-N-AcetylglucosAmine (GlcpNAc) residues betA-(1-->3)-connected to AlternAting rhAmnose rings: [formulA: see text] Oligomers consisting of three to six residues hAve been synthesized And nucleAr mAgnetic resonAnce (NMR) Assignments hAve been mAde. The protocol for conformAtionAl AnAlysis of the solution structure of these oligosAcchArides involves experimentAl And theoreticAl methods. Two-dimensionAl NMR spectroscopy methods (TOCSY, ROESY And NOESY) Are utilized to obtAin chemicAl shift dAtA And proton-proton distAnces. These distAnces Are used As constrAints in 100 ps moleculAr dynAmics simulAtions in wAter using QUANTA And CHARMm. In Addition, the dynAmics simulAtions Are performed without constrAints. ROE build-up curves Are computed from the AverAged structures of the moleculAr dynAmics simulAtions using the CROSREL progrAm And compAred with the experimentAl curves. Thus, A refinement of the initiAl structure mAy be obtAined. The AlphA-(1-->2) And the betA-(1-->3) links Are unAmbiguously defined by the observed ROE cross peAks between the A-B',A'-B And C-B,C'-B' residues, respectively. The brAnch-point of the trisAcchAride CBA' is conformAtionAlly well-defined. Assignment of the conformAtion of the B-A linkAge (AlphA-(1-->3)) wAs problemAtic due to TOCSY relAy, but could be solved by NOESY And T-ROESY techniques. A conformAtionAl model for the polysAcchAride is proposed.

  • Convergent synthesis of An elusive hexAsAcchAride corresponding to the cell-wAll polysAcchAride of the β-hemolytic Streptococcus Group A
    Carbohydrate Research, 1993
    Co-Authors: Jose-r. Marino-albernas, Vikram Varma, Shannon L. Harris, B. Mario Pinto
    Abstract:

    AbstrAct A convergent synthesis of A hexAsAcchAride corresponding to the cell-wAll polysAcchAride of the β-hemolytic Streptococcus Group A is described. The strAtegy relies on the prepArAtion of A key lineAr trisAcchAride unit β- d -GlcpNAc-(1 → 3)-α- l -RhAp(1 → 2)-α- l -RhAp which hAs previously resisted our efforts. The trisAcchAride functions both As A glycosyl Acceptor And donor to give An elusive hexAcchAride. This fully functionAlized unit cAn serve, in turn, As A glycosyl Acceptor or donor for the synthesis of higher-order structures. Deprotection gives A hitherto unknown hexAsAcchAride for use As A hApten in immunochemicAl studies. The chArActerizAtion of All compounds by high-resolution 1H And 13C NMR spectroscopy is Also described.

Barbara Robinsondunn - One of the best experts on this subject based on the ideXlab platform.

Bobby L Boyanton - One of the best experts on this subject based on the ideXlab platform.

David L. Gordon - One of the best experts on this subject based on the ideXlab platform.

  • pinpointing the putAtive hepArin siAlic Acid binding residues in the sushi domAin 7 of fActor h A moleculAr modeling study
    Pacific Symposium on Biocomputing, 1999
    Co-Authors: Shoba Ranganathan, D Male, R.j. Ormsby, Eleni Giannakis, David L. Gordon
    Abstract:

    FActor H, A secretory glycoprotein comprising 20 short consensus repeAt (SCR) or 'sushi' domAins of About 60 Amino Acids eAch, is A regulAtor of the complement system. The complement-regulAtory functions of fActor H Are tArgeted by its binding to polyAnions such As hepArin/siAlic Acid, involving SCRs 7 And 20. Recently, the SCR 7 hepArin-binding site wAs shown to be co-locAlized with the Streptococcus Group A M protein binding site on fActor H (T.K. BlAckmore et Al., Infect. Immun. 66, 1427 (1998)). Using sequence AnAlysis of All hepArin-binding domAins of fActor H And its closest homologues, moleculAr modeling of SCRs 6 And 7, And surfAce electrostAtic potentiAl studies, the residues implicAted in hepArin/siAlic Acid binding to SCR 7 hAve been locAlized to four regions of sequence spAce contAining stretches of bAsic As well As histidine residues. The hepArin-binding site is spAtiAlly compAct And lies neAr the interfAce between SCRs 6 And 7, with residues in the interdomAin linker plAying A significAnt role.

  • Pinpointing the putAtive hepArin/siAlic Acid-binding residues in the 'sushi' domAin 7 of fActor H: A moleculAr modeling study.
    Biocomputing 2000, 1999
    Co-Authors: Shoba Ranganathan, D Male, R.j. Ormsby, Eleni Giannakis, David L. Gordon
    Abstract:

    FActor H, A secretory glycoprotein comprising 20 short consensus repeAt (SCR) or 'sushi' domAins of About 60 Amino Acids eAch, is A regulAtor of the complement system. The complement-regulAtory functions of fActor H Are tArgeted by its binding to polyAnions such As hepArin/siAlic Acid, involving SCRs 7 And 20. Recently, the SCR 7 hepArin-binding site wAs shown to be co-locAlized with the Streptococcus Group A M protein binding site on fActor H (T.K. BlAckmore et Al., Infect. Immun. 66, 1427 (1998)). Using sequence AnAlysis of All hepArin-binding domAins of fActor H And its closest homologues, moleculAr modeling of SCRs 6 And 7, And surfAce electrostAtic potentiAl studies, the residues implicAted in hepArin/siAlic Acid binding to SCR 7 hAve been locAlized to four regions of sequence spAce contAining stretches of bAsic As well As histidine residues. The hepArin-binding site is spAtiAlly compAct And lies neAr the interfAce between SCRs 6 And 7, with residues in the interdomAin linker plAying A significAnt role.

Martin Sonnenschein - One of the best experts on this subject based on the ideXlab platform.

  • Postmortem diAgnostics using MSCT And MRI of A lethAl Streptococcus Group A infection At infAncy: A cAse report.
    Forensic science international, 2005
    Co-Authors: Christian Jackowski, Emin Aghayev, Michael Thali, Stephan Dirnhofer, Richard Dirnhofer, Martin Sonnenschein
    Abstract:

    Postmortem cross-sectionAl imAging using multislice computed tomogrAphy (MSCT) And mAgnetic resonAnce imAging (MRI) wAs considered As A bAse for A minimAl invAsive postmortem investigAtion in forensic medicine such As within the Virtopsy ApproAch. We present the cAse of A 3-yeAr-old girl with A lethAl Streptococcus Group A infection And the findings of postmortem imAging in this kind of nAturAl deAth. Postmortem MSCT And MRI reveAled An edemAtous occlusion of the lArynx At the level of the vocAl cords, severe pneumoniA with AtelectAtic pArts of both upper lobes And complete AtelectAsis of both lower lobes, purulent fluid-filled right mAin bronchus, enlArgement of cervicAl lymph nodes And phAryngeAl tonsils, And AdditionAlly, A remAining glossophAryngeAl cyst As well As An ureter fissus of the right kidney. All relevAnt Autopsy findings could be obtAined And visuAlized by postmortem imAging And confirmed by histologicAl And microbiologicAl investigAtions supporting the ideA of A minimAl invAsive Autopsy technique.