A basic region neighboring the lysine-rich C-terminus of protein SRP19 is required for binding to signal recognition particle RNA.
To identify some of the determinants in the 19-kilodalton protein of signal recognition particle (SRP19) for binding to signal recognition particle RNA, two mutant derivatives of the SRP19 were constructed, lacking 14 and 24 C-terminal amino acids. Polypeptides were transcribed and translated in vitro and tested for their ability to bind to signal recognition particle RNA by retention of protein-RNA complexes on DEAE-Sepharose. Both mutant polypeptides form complexes with the RNA, demonstrating that the 24 C-terminal amino acids, which include a lysine-rich sequence at positions 136-144, are dispensable. A third mutant polypeptide, in which eight additional amino acids were removed by oligonucleotide-directed digestion of the mRNA, was unable to bind. The amino acids in the sequence PKLKTRTQ correspond to positions 113-120; they are suggested to be involved in interaction with signal recognition particle RNA.
Zwieb
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Department of Molecular Biology, University of Texas Health Center, Tyler 75710.
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D001665:Binding Sites; D008239:Lysine / Q000737:chemistry; D008969:Molecular Sequence Data; D009154:Mutation; D014176:Protein Biosynthesis; D012313:RNA / Q000378:metabolism*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D051381:Rats; D012261:Ribonucleoproteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D018271:Signal Recognition Particle; D014158:Transcription, Genetic
D012333:RNA, Messenger; D012261:Ribonucleoproteins; D018271:Signal Recognition Particle; D012313:RNA; D008239:Lysine