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The RNase E of Escherichia coli has at least two binding sites for DEAD‐box RNA helicases: functional replacement of RhlB by RhlE
Author(s) -
Khemici Vanessa,
Toesca Isabelle,
Poljak Leonora,
Vanzo Nathalie F.,
Carpousis Agamem J.
Publication year - 2004
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1111/j.1365-2958.2004.04361.x
Subject(s) - rnase p , biology , rna helicase a , rna , dead box , degradosome , helicase , escherichia coli , in vitro , biochemistry , microbiology and biotechnology , gene
Summary The non‐catalytic region of Escherichia coli RNase E contains a protein scaffold that binds to the other components of the RNA degradosome. Alanine scanning yielded a mutation, R730A, that disrupts the interaction between RNase E and the DEAD‐box RNA helicase, RhlB. We show that three other DEAD‐box helicases, SrmB, RhlE and CsdA also bind to RNase E in vitro . Their binding differs from that of RhlB because it is not affected by the R730A mutation. Furthermore, the deletion of residues 791–843, which does not affect RhlB binding, disrupts the binding of SrmB, RhlE and CsdA. Therefore, RNase E has at least two RNA helicase binding sites. Reconstitution of a complex containing the protein scaffold of RNase E, PNPase and RhlE shows that RhlE can furnish an ATP‐dependent activity that facilitates the degradation of structured RNA by PNPase. Thus, RhlE can replace the function of RhlB in vitro . The results in the accompanying article show that CsdA can also replace RhlB in vitro . Thus, RhlB, RhlE and CsdA are interchangeable in in vitro RNA degradation assays.