a particle sedimenting at 42s contains 5s rna and trna together with two proteins of mr 48000 ( p48 ) and mr 43000 ( p43 ) and a second particle sedimenting at 7s contains 5s rna plus a protein of mr 40000 ( p40 , also known as the transcription factor , tfiiia ) .
C0033684
proteins
C0040648
transcription factor