when sm monoclonal antibody ( specific for the b ' , b , and d proteins of u snrnps ) was bound to u1 snrnps prior to micrococcal nuclease digestion , the same approximately equal to 24 nucleotide fragment of u1 rna ( corresponding to nucleotides 120-143 and termed the `` '' sm domain '' '' ) was protected as when no antibody was bound prior to digestion .
C0587072
sm
C0003241
antibo