[Features of the structure of catalytic subunits of toxins, inhibiting protein synthesis. I. The effect of pH and interaction with the B-chain of ricin].
A comparative study of gelonin and A-chains of ricin, mistletoe lectin I and diphtheria toxin was undertaken. The effect of pH was studied on: a) the conformation of the proteins under study using intrinsic fluorescence; b) interaction of these proteins with ricin B-chain using gel-filtration. Structural stability of the proteins was assessed according to denaturing action of guanidine hydrochloride and temperature, and localization of tryptophan residues was determined using fluorescence quenching by I-, Cs+ and acrylamide. All investigated proteins were shown to undergo the conformational changes when a environment became acidic. In comparison with an intact protein--gelonin, the A-chains of ricin, a mistletoe lectin and a diphtheria toxin are less stable. At pH less than 5.0 tryptophan residues became more accessible to quencher and a positive charge of the surrounding area increases (in the case of gelonin it is negatively charged). No reliable interaction of a ricin B-chain with both gelonin and A-chain of diphtheria toxin was observed. The interaction of a ricin B-chain with a A-chain of mistletoe lectin I is weaker than that with ricin A-chain and is practically pH-independent.
Bushueva
T L
TL
Uroshevich
O I
OI
Maĭsurian
N A
NA
Mirimanova
N V
NV
Tonevitskiĭ
A G
AG
D002384:Catalysis; D002850:Chromatography, Gel; D004167:Diphtheria Toxin / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D009994:Osmolar Concentration; D028321:Plant Preparations; D010940:Plant Proteins / Q000378:metabolism; D011500:Protein Synthesis Inhibitors / Q000378:metabolism*; D054789:Ribosome Inactivating Proteins, Type 1; D054790:Ribosome Inactivating Proteins, Type 2; D012276:Ricin / Q000378:metabolism*; D013050:Spectrometry, Fluorescence; D013696:Temperature; D014118:Toxins, Biological / Q000378:metabolism*; D014364:Tryptophan
D004167:Diphtheria Toxin; D028321:Plant Preparations; D010940:Plant Proteins; D011500:Protein Synthesis Inhibitors; D054789:Ribosome Inactivating Proteins, Type 1; D054790:Ribosome Inactivating Proteins, Type 2; D014118:Toxins, Biological; C009674:ribosome inactivating protein, Viscum; C025674:GEL protein, Gelonium multiflorum; D014364:Tryptophan; D012276:Ricin
Osobennosti struktury kataliticheskikh sub''edinits toksinov, ingibiruiushchikh belkovyĭ sintez. I. Vliianie pH, vzaimodeĭstvie s B-tsep'iu ritsina.