| Autor: |
Moehring, J M, Moehring, T J, Danley, D E |
| Zdroj: |
Proceedings of the National Academy of Sciences of the United States of America; February 1980, Vol. 77 Issue: 2 p1010-1014, 5p |
| Abstrakt: |
We have identified two types of mutants of Chinese hamster ovary cells in which the unique ADP-ribose attachment site in elongation factor 2 (EF-2) is altered, thereby rendering them resistant to diphtheria and Pseudomonas toxins (TOXR). The first is mutant in the gene for EF-2 and possesses a permanently altered, TOXR gene product. The second lacks a component of a posttranslational modification system that converts TOXR EF-2 to the toxin-sensitive (TOXS) state. We postulate that this modification system is involved in the conversion of a single histidine residue in EF-2 to the specific target of toxin-catalyzed ADP-ribosylation, the novel amino acid X. We have designated the second type MOD- mutants. The missing of nonfunctional component in the MOD- mutants can be restored by hybridizing them with either normal TOXS cells or with EF-2 structural gene mutants. The TOXR EF-2 from MOD- mutants is also converted to toxin sensitivity in vitro by incubation with extracts of TOXS or EF-2 gene mutant cells in the presence of an energy-generating system. Our results demonstrate that EF-2 can be synthesized and released from ribosomes in a toxin-resistant form and then converted to toxin sensitivity by posttranslational modification. |
| Databáze: |
Supplemental Index |
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