Abstract
Oligoribonuclease, a 3′-to-5′ exoribonuclease specific for small oligoribonucleotides, was purified to homogeneity from extracts of
Escherichia coli
. The purified protein is an α2 dimer of 40 kDa. NH
2
-terminal sequence analysis of the protein identified the gene encoding oligoribonuclease as
yjeR
(
o204a
), a previously reported open reading frame located at 94 min on the
E. coli
chromosome. However, as a consequence of the sequence information, the translation start site of this open reading frame has been revised. Cloning of
yjeR
led to overexpression of oligoribonuclease activity, and interruption of the cloned gene with a kanamycin resistance cassette eliminated the overexpression. On the basis of these data, we propose that
yjeR
be renamed
orn
. Orthologs of oligoribonuclease are present in a wide range of organisms, extending up to humans.
