phe-trna of escherichia coli , specifically derivatized at the s4u8 position with the 9 a long p-azidophenacyl photoaffinity probe , was crosslinked exclusively to protein s19 of the 30 s ribosomal subunit when the transfer rna occupied the ribosomal a site ( lin et al. , 1983 ) .
C0073320
protein s19
C0035553
ribosomal