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Effects of some proteins that inactivate the eukaryotic ribosome
Author(s) -
Fernandez-Puentes C.,
Vazquez D.
Publication year - 1977
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(77)80292-5
Subject(s) - chemistry
The glycoproteins abrin and ricin ([l] review) and the proteins PAP [2], alpha sarcin (J. E. Davies, personal communication), cretin II [3], curcin II [3] , enomycin [4] and phenomycin [S] have been reported to block translation by eukaryotic ribosomes. The glycoproteins abrin and ricin are very active in intact cells since they are composed of two subunits, one of which (the B chain) facilitates the entrance into the cell of the other subunit (the A chain), which catalytically inactivates the 60 S ribosomal subunits ([ 1 ] review). However ricin A chain and the individual proteins abrin A chain, PAP, alpha sarcin, cretin II, curcin II, enomycin and phenomycin are very active in blocking translation in cell-free systems but far less so in intact cells probably owing to the cellular permeability barrier [l--S]. All these toxins might have a similar or related mechanism of action since abrin A chain [6], ricin A chain [6], PAP [2], cretin 11 [3], alpha sarcin (J. E. Davies, personal communication) and enomycin [4,7] were observed to have a certain inhibitory effect on the EF l-dependent binding of aminoacyl-tRNA to the ribosome. However the mode of action of the toxins has been studied independently by different groups using different cells and cell-free systems and it is not possible to conclude from the results available whether or not the toxins act in a similar manner. We have therefore studied comparatively the effects of ricin and abrin with PAP, alpha sarcin and enomycin on the EF l-dependent binding of aminoacyl-tRNA, formation of the EF 2-GTP-ribosome complex, peptidyl-tRNA translocation and EF 2and ribosome-dependent GTP hydrolysis using