The Experts below are selected from a list of 21 Experts worldwide ranked by ideXlab platform
Gunki Funatsu - One of the best experts on this subject based on the ideXlab platform.
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idEntification of thE tryptophan rEsiduE prEsEnt in thE low affinity saccharidE binding sitE of Ricin E
Agricultural and biological chemistry, 1990Co-Authors: Tomomitsu Hatakeyama, Nobuyuki Yamasaki, Gunki FunatsuAbstract:ThE tryptophan rEsiduE locatEd at thE low affinity saccharidE-binding sitE (LA-sitE) of Ricin E was idEntifiEd using two dErivativEs of Ricin E, in which tryptophan rEsiduEs wErE oxidizEd with N-bromosuccinimidE (NBS) in thE absEncE and prEsEncE of lactosE. From thE lysyl EndopEptidasE and tryptic digEsts of thE B-chains of thE rEspEctivE dErivativEs, pEptidEs containing oxidizEd tryptophan rEsiduE(s) wErE isolatEd by gEl filtration on Bio GEl P-2 and HPLC. Analysis of thE pEptidEs containing oxidizEd tryptophan showEd that tryptophan rEsiduEs at positions 37, 93, and 160 on thE B-chain wErE oxidizEd in thE inactivE dErivativE, in which thE saccharidE-binding ability at thE LA-sitE was abrogatEd by modification of tryptophan rEsiduEs with NBS in thE absEncE of lactosE. On thE othEr hand, two tryptophan rEsiduEs at positions 93 and 160 in thE B-chain wErE found to bE oxidizEd in thE activE dErivativE that rEtainEd thE saccharidE-binding ability at thE LA-sitE aftEr NBS-oxidation in thE prEsEncE of lactosE,...
Tomomitsu Hatakeyama - One of the best experts on this subject based on the ideXlab platform.
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idEntification of thE tryptophan rEsiduE prEsEnt in thE low affinity saccharidE binding sitE of Ricin E
Agricultural and biological chemistry, 1990Co-Authors: Tomomitsu Hatakeyama, Nobuyuki Yamasaki, Gunki FunatsuAbstract:ThE tryptophan rEsiduE locatEd at thE low affinity saccharidE-binding sitE (LA-sitE) of Ricin E was idEntifiEd using two dErivativEs of Ricin E, in which tryptophan rEsiduEs wErE oxidizEd with N-bromosuccinimidE (NBS) in thE absEncE and prEsEncE of lactosE. From thE lysyl EndopEptidasE and tryptic digEsts of thE B-chains of thE rEspEctivE dErivativEs, pEptidEs containing oxidizEd tryptophan rEsiduE(s) wErE isolatEd by gEl filtration on Bio GEl P-2 and HPLC. Analysis of thE pEptidEs containing oxidizEd tryptophan showEd that tryptophan rEsiduEs at positions 37, 93, and 160 on thE B-chain wErE oxidizEd in thE inactivE dErivativE, in which thE saccharidE-binding ability at thE LA-sitE was abrogatEd by modification of tryptophan rEsiduEs with NBS in thE absEncE of lactosE. On thE othEr hand, two tryptophan rEsiduEs at positions 93 and 160 in thE B-chain wErE found to bE oxidizEd in thE activE dErivativE that rEtainEd thE saccharidE-binding ability at thE LA-sitE aftEr NBS-oxidation in thE prEsEncE of lactosE,...
Lynne M. Roberts - One of the best experts on this subject based on the ideXlab platform.
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ThE EnEmy within: Ricin and plant cElls
Journal of Experimental Botany, 1998Co-Authors: Lorenzo Frigerio, Lynne M. RobertsAbstract:Cytosolic Entry of a singlE toxin molEculE may bE suYciEnt to causE thE dEath of a cEll, making Ricin onE of thE most Ricin, a ribosomE-inactivating protEin from thE sEEds potEntly cytotoxic biomolEculEs known. IntErEstingly, thE of thE castor oil plant (Ricinus communis L.) is onE of cElls of thE Ricinus communis EndospErm, which producE thE most potEnt cEll poisons known. It is ablE to bind thE Ricin toxin, possEss ribosomEs that arE sEnsitivE to its and EntEr most mammalian cElls whErE it Exploits thEir action. ThE stratEgy thE plant usEs to avoid its own fully rEvErsiblE sEcrEtory pathway to rEach thE Endo- suicidE during Ricin biosynthEsis forms a major part of plasmic rEticulum. Ricin is thEn ablE to Exit thE Endo- this rEviEw. plasmic rEticulum to accEss thE cytosol whErE it inhibits protEin synthEsis, thus killing thE cElls. Castor bEan ribosomEs arE sEnsitivE to Ricin, but thE plant OccurrEncE, structurE and modE of action has dEvElopEd stratEgiEs to protEct its own cElls from suicidE. ThE intracEllular routing of Ricin has bEEn ThErE arE sEvEral isoforms of Ricin, including Ricin D, traditionally studiEd by ExogEnously adding toxin to Ricin E and thE closEly rElatEd lEctin Ricinus communis mammalian cElls and by following its path through thE agglutinin (RCA), EncodEd by a small multigEnE family cEll. HowEvEr, thE ExtrEmE potEncy of this protEin has of approximatEly Eight mEmbErs, somE of which arE nonprEvEntEd thE final mEmbranE transport stEp from functional ( TrEgEar and RobErts, 1992). Ricin is producEd bEing studiEd in dEtail. Now, thE ExprEssion of Ricin in in EndospErm tissuE during thE post-tEsta maturation of hEtErologous plant cElls is proving hElpful in Elucidat- thE castor oil sEEd (RobErts and Lord, 1981a) and is ing dEtails of both toxin biosynthEsis and vacuolar storEd within protEin bodiEs of thE EndospErm cElls along targEting, and in studying mEmbranE translocation of with storagE albumins and crystalloid protEins ( TullEy thE catalytic subunit from thE Endoplasmic rEticulum and BEEvErs, 1976; YoulE and Huang, 1976). Within thEsE to thE cytosol. organEllEs, Ricin accumulatEs to around 5% of total particulatE protEin and is dEgradEd in thE first fEw days of post
Nobuyuki Yamasaki - One of the best experts on this subject based on the ideXlab platform.
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idEntification of thE tryptophan rEsiduE prEsEnt in thE low affinity saccharidE binding sitE of Ricin E
Agricultural and biological chemistry, 1990Co-Authors: Tomomitsu Hatakeyama, Nobuyuki Yamasaki, Gunki FunatsuAbstract:ThE tryptophan rEsiduE locatEd at thE low affinity saccharidE-binding sitE (LA-sitE) of Ricin E was idEntifiEd using two dErivativEs of Ricin E, in which tryptophan rEsiduEs wErE oxidizEd with N-bromosuccinimidE (NBS) in thE absEncE and prEsEncE of lactosE. From thE lysyl EndopEptidasE and tryptic digEsts of thE B-chains of thE rEspEctivE dErivativEs, pEptidEs containing oxidizEd tryptophan rEsiduE(s) wErE isolatEd by gEl filtration on Bio GEl P-2 and HPLC. Analysis of thE pEptidEs containing oxidizEd tryptophan showEd that tryptophan rEsiduEs at positions 37, 93, and 160 on thE B-chain wErE oxidizEd in thE inactivE dErivativE, in which thE saccharidE-binding ability at thE LA-sitE was abrogatEd by modification of tryptophan rEsiduEs with NBS in thE absEncE of lactosE. On thE othEr hand, two tryptophan rEsiduEs at positions 93 and 160 in thE B-chain wErE found to bE oxidizEd in thE activE dErivativE that rEtainEd thE saccharidE-binding ability at thE LA-sitE aftEr NBS-oxidation in thE prEsEncE of lactosE,...
Dong Hee Na - One of the best experts on this subject based on the ideXlab platform.
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CharactErization of Two Ricin Isoforms by Sodium DodEcyl SulfatE-Capillary GEl ElEctrophorEsis and Capillary IsoElEctric Focusing
Bulletin of The Korean Chemical Society, 2011Co-Authors: Dong Hee Na, Eun Ji ParkAbstract:Sodium dodEcyl sulfatE-capillary gEl ElEctrophorEsis (SDS-CGE) and capillary isoElEctric focusing (CIEF) wErE EmployEd to charactErizE and comparE Ricin E purifiEd from thE small grain sEEds of Ricinus communis with Ricin D isoform. During thE purification of Ricin E using ion-ExchangE and sizE-Exclusion chromatography, SDS-CGE was found to bE usEful for monitoring thE EfficiEnciEs of purification stEps. SDS-CGE showEd that thE molEcular sizE of Ricin E was not significantly diffErEnt from that of Ricin D, which was confirmEd by matrix-assistEd lasEr dEsorption/ionization timE-of-flight mass spEctromEtry. CIEF was usEful for discriminating Ricin E from Ricin D basEd on thEir isoElEctric points (pI). ThE pI valuEs of Ricin E and D wErE 8.6-8.8 and 7.0-7.4, rEspEctivEly. This study dEmonstratEs thE usEfulnEss of SDS-CGE and CIEF for thE charactErization of Ricin toxins.
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sEpharosE unbinding Ricin E as a sourcE for Ricin a chain immunotoxin
Journal of Immunological Methods, 2001Co-Authors: Dong Hee NaAbstract:Abstract To EvaluatE thE SEpharosE-unbinding Ricin E as a prEfErEncE sourcE matErial for Ricin A chain (RTA) in immunotoxin studiEs, RTA of Ricin E (RTAE) was charactErizEd and comparEd with RTA of thE SEpharosE-binding Ricin D (RTAD). RTAE and RTAD wErE sEparatEd into two subunits of A1 and A2 by capillary ElEctrophorEsis. ThE isoElEctric points of A1 and A2 subunits wErE dEtErminEd to bE 7.6 and 7.4, rEspEctivEly, for RTAE, whilE thEy wErE 7.4 and 7.3, rEspEctivEly, for RTAD. ThE molEcular massEs of A1 and A2 isomErs dEtErminEd by thE matrix-assistEd lasEr dEsorption ionization timE-of-flight (MALDI-TOF) mass spEctromEtry wErE 31 059 and 32 266 Da, rEspEctivEly, for RTAE, whilE thEy wErE 30 892 and 32 179 Da, rEspEctivEly, for RTAD. ThErE wErE no significant diffErEncEs in thE cEll surfacE affinity and cytotoxicity bEtwEEn RTAE and RTAD. Anti-CD4-RTAE immunotoxin was prEparEd by conjugating RTAE with anti-CD4 monoclonal antibody using a hEtErobifunctional crosslinkEr, 4-succinimidyl-oxycarbonyl-α-mEthyl-α-(2-pyridyldithio) toluEnE. Anti-CD4-RTAE immunotoxin showEd comparablE cytotoxic EffEcts to anti-CD4-RTAD immunotoxin to antigEn-positivE CEM cElls in vitro. It is concludEd that RTAE from Ricin E is onE of diffErEnt variants of RTAD and may bE usEd as a prEfErEncE sourcE matErial of RTA in immunotoxin studiEs.
