Substrate binding and active site residues in RNases E and G: role of the 5'-sensor.

ABSTRACT: The paralogous endoribonucleases, RNase E and RNase G, play major roles in intracellular RNA metabolism in Escherichia coli and related organisms. To assay the relative importance of the principal RNA binding sites identified by crystallographic analysis, we introduced mutations into the 5'-sensor, the S1 domain, and the Mg(+2)/Mn(+2) binding sites. The effect of such mutations has been measured by assays of activity on several substrates as well as by an assay of RNA binding. RNase E R169Q and the equivalent mutation in RNase G (R171Q) exhibit the strongest reductions in both activity (the k(cat) decrease approximately 40- to 100-fold) and RNA binding consistent with a key role for the 5'-sensor. Our analysis also supports a model in which the binding of substrate results in an increase i

SUBMITTER: Garrey SM 

PROVIDER: S-EPMC2797255 | biostudies-literature | 2009 Nov

REPOSITORIES: biostudies-literature