Abstract
Arginine methylation is a post-translational modification found mostly in RNA-binding proteins. Poly(A)-binding protein II from calf thymus was shown by mass spectrometry and sequencing to contain NG, NG-dimethylarginine at 13 positions in its amino acid sequence. Two additional arginine residues were partially methylated. Almost all of the modified residues were found in Arg-Xaa-Arg clusters in the C terminus of the protein. These motifs are distinct from Arg-Gly-Gly motifs that have been previously described as sites and specificity determinants for asymmetric arginine dimethylation. Poly(A)-binding protein II and deletion mutants expressed in Escherichia coli were in vitro substrates for two mammalian protein arginine methyltransferases, PRMT1 and PRMT3, with S-adenosyl-L-methionine as the methyl group donor. Both PRMT1 and PRMT3 specifically methylated arginines in the C-terminal domain corresponding to the naturally modified sites.
Highlights
Poly(A)-binding protein II (PABP2)1 is a protein of 33 kDa that binds poly(A) with high affinity and specificity
A characteristic feature of the RGG motif is the post-translational modification of arginine residues to NG,NG-dimethylarginine (NG,NG-DMA) (18 –23)
A second mammalian methyltransferase termed PRMT3 has been cloned. This enzyme methylates a glutathione-S-transferase (GST) fusion protein containing a glycineand arginine-rich region from human fibrillarin, GST-GAR, no natural protein substrates have yet been identified for PRMT3 in heated hypomethylated rat cell extracts
Summary
Poly(A)-binding protein II (PABP2)1 is a protein of 33 kDa that binds poly(A) with high affinity and specificity. The observed masses of all the above-mentioned fragments were in very close agreement with the masses predicted from the cDNA sequence, indicating no modification of amino acid residues. Fragment Lys-C7, corresponding to Met-167–Lys-207, contained two arginine residues, Arg-172 and Arg-200.
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
