Isolation and characterization of four type 2 ribosome inactivating pulchellin isoforms from Abrus pulchellus seeds.

摘要: Abrus pulchellus seeds contain at least seven closely related and highly toxic type 2 ribosome-inactivating pulchellins, each consisting of a A-chain linked to sugar binding B-chain. In the present study, four pulchellin isoforms (termed P I, II, III IV) were isolated by affinity, ion exchange chromatofocusing chromatographies, investigated with respect toxicity specificity. Half maximal inhibitory concentration median lethal dose values indicate that I II have similar toxicities both are more cultured HeLa cells mice than IV. Interestingly, secondary structural characteristics properties respective pairs correlate well two levels, in I/P III/P IV form specific subgroups. From deduced amino acids sequences isoforms, it is clear highest similarity within subgroup found occur domain B-chains, suggesting disparity levels might be attributed subtle differences B-chain-mediated cell surface interactions precede determine toxin uptake pathways.