Analysis of toxicity in Escherichia coli from the expression of human purinergic receptor P2X 4

초록

In general, expression of membrane protein in Escherichia coli is very toxic to the host organism, but the mechanism for the toxicity is not clear yet. Expression of human purinergic receptor P2X 4 was found to be extremely toxic to the host E. coli. We examined this toxicity by isolation and analysis of less toxic mutant proteins. We could isolate 30 less toxic mutants of P2X 4 after hydroxylamine mutagenesis. Western blot showed that all of them produced proteins smaller than the wild type P2X 4. DNA sequencing of two largest mutant proteins showed that they were lost its second transmembrane domain. Localization analysis of these mutant proteins showed that they are not in cytoplasmic membrane, but in inclusion bodies. These data showed that inactive truncated P2X 4 is not toxic to E. coli and membrane integration and functionality of P2X 4 may be needed to show host toxicity. © 2011, The Microbiological Society of Korea.

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