Cooperativity in low-affinity Mg2+ binding to tRNA.

نویسندگان

  • D Labuda
  • K Nicoghosian
  • R Cedergren
چکیده

The Pb2+-catalyzed cleavage of tRNAPhe has been used to probe the effect of Na+ and Mg2+ binding to tRNA. Na+ is a noncompetitive inhibitor of the Pb2+-catalyzed cleavage. Millimolar Mg2+ is also a noncompetitive inhibitor. Analysis of the Mg2+ data show that at least two sites are involved in binding and that there is an interaction between the sites (cooperativity). Low-affinity Mg2+ binding is thus different from "weak" and "strong" Mg2+ binding to tRNA characterized previously. We postulate that the alterations induced by low-affinity Mg2+ binding in tRNA mimic to some extent those brought about in RNA by the interaction with a protein factor and that at appropriate [Mg2+] the whole structure of tRNA is able to respond in a concerted way to a signal from the environment such as aminoacylation or codon binding.

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عنوان ژورنال:
  • The Journal of biological chemistry

دوره 260 2  شماره 

صفحات  -

تاریخ انتشار 1985