The pooled sample was then loaded onto a Mono Q
FPLC column. The RNA binding protein was eluted between
120 and 300 mM NaCl. The active fractions from the Mono Q
column were then concentrated and loaded on an Superose 12
FPLC column. Active fractions from the Superose 12 column
were then subjected to butyl C4 reverse phase (r) HPLC. To test
for the binding activity from fractions eluted from the rHPLC
column, it was necessary to remove acetonitrile by lyophilizing
the fractions and dissolving them in 10 mM Tris HCl (pH 7.4).
To obtain the RV RNA binding protein as a single polypeptide,
active fractions from the HPLC column were pooled, concentrated,
and separated by HPEC. Fractions containing a single
protein band in silver-stained SDS/PAGE gels were pooled and
concentrated.