Linked Life Data

11948193

Source:http://linkedlifedata.com/resource/pubmed/id/11948193

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
24
pubmed:dateCreated
2002-6-10
pubmed:abstractText
Escherichia coli RNase R, a 3' --> 5' exoribonuclease homologous to RNase II, was overexpressed and purified to near homogeneity in its native untagged form by a rapid procedure. The purified enzyme was free of nucleic acid. It migrated upon gel filtration chromatography as a monomer with an apparent molecular mass of approximately 95 kDa, in close agreement with its expected size based on the sequence of the rnr gene. RNase R was most active at pH 7.5-9.5 in the presence of 0.1-0.5 mm Mg(2+) and 50-500 mm KCl. The enzyme shares many catalytic properties with RNase II. Both enzymes are nonspecific processive ribonucleases that release 5'-nucleotide monophosphates and leave a short undigested oligonucleotide core. However, whereas RNase R shortens RNA processively to di- and trinucleotides, RNase II becomes more distributive when the length of the substrate reaches approximately 10 nucleotides, and it leaves an undigested core of 3-5 nucleotides. Both enzymes work on substrates with a 3'-phosphate group. RNase R and RNase II are most active on synthetic homopolymers such as poly(A), but their substrate specificities differ. RNase II is more active on poly(A), whereas RNase R is much more active on rRNAs. Neither RNase R nor RNase II can degrade a complete RNA-RNA or DNA-RNA hybrid or one with a 4-nucleotide 3'-RNA overhang. RNase R differs from RNase II in that it cannot digest DNA oligomers and is not inhibited by such molecules, suggesting that it does not bind DNA. Although the in vivo function of RNase R is not known, its ability to digest certain natural RNAs may explain why it is maintained in E. coli together with RNase II.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jun
pubmed:issn
0021-9258
pubmed:author
pubmed:issnType
Print
pubmed:day
14
pubmed:volume
277
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
21624-9
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
2002
pubmed:articleTitle
Purification and characterization of the Escherichia coli exoribonuclease RNase R. Comparison with RNase II.
pubmed:affiliation
Department of Biochemistry and Molecular Biology, University of Miami School of Medicine, Miami, Florida 33101, USA.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S.