TY - JOUR
T1 - How RNase R degrades structured RNA
T2 - Role of the helicase activity and the S1 domain
AU - Hossain, Sk Tofajjen
AU - Malhotra, Arun
AU - Deutscher, Murray P.
N1 - Funding Information:
This work was supported by National Institutes of Health Grant GM 16317 (to M.P.D.).
PY - 2016/4/8
Y1 - 2016/4/8
N2 - RNase R, a ubiquitous 3′ exoribonuclease, plays an important role in many aspects of RNA metabolism. In contrast to other exoribonucleases, RNase R can efficiently degrade highly structured RNAs, but the mechanism by which this is accomplished has remained elusive. It is known that RNase R contains an unusual, intrinsic RNA helicase activity that facilitates degradation of duplex RNA, but how it stimulates the nuclease activity has also been unclear. Here, we have made use of specifically designed substrates to compare the nuclease and helicase activities of RNase R. We have also identified and mutated several residues in the S1 RNA-binding domain that are important for interacting with duplex RNA and have measured intrinsic tryptophan fluorescence to analyze the conformational changes that occur upon binding of structured RNA. Using these approaches, we have determined the relation of the RNA helicase, ATP binding, and nuclease activities of RNase R. This information has been combined with a structural analysis of RNase R, based on its homology to RNase II, whose structure has been determined, to develop a detailed model that explains how RNase R digests structured RNA and how this differs from its action on single-stranded RNA.
AB - RNase R, a ubiquitous 3′ exoribonuclease, plays an important role in many aspects of RNA metabolism. In contrast to other exoribonucleases, RNase R can efficiently degrade highly structured RNAs, but the mechanism by which this is accomplished has remained elusive. It is known that RNase R contains an unusual, intrinsic RNA helicase activity that facilitates degradation of duplex RNA, but how it stimulates the nuclease activity has also been unclear. Here, we have made use of specifically designed substrates to compare the nuclease and helicase activities of RNase R. We have also identified and mutated several residues in the S1 RNA-binding domain that are important for interacting with duplex RNA and have measured intrinsic tryptophan fluorescence to analyze the conformational changes that occur upon binding of structured RNA. Using these approaches, we have determined the relation of the RNA helicase, ATP binding, and nuclease activities of RNase R. This information has been combined with a structural analysis of RNase R, based on its homology to RNase II, whose structure has been determined, to develop a detailed model that explains how RNase R digests structured RNA and how this differs from its action on single-stranded RNA.
UR - http://www.scopus.com/inward/record.url?scp=84964681370&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84964681370&partnerID=8YFLogxK
U2 - 10.1074/jbc.M116.717991
DO - 10.1074/jbc.M116.717991
M3 - Article
C2 - 26872969
AN - SCOPUS:84964681370
VL - 291
SP - 7877
EP - 7887
JO - Journal of Biological Chemistry
JF - Journal of Biological Chemistry
SN - 0021-9258
IS - 15
ER -