Protein methyltransferase activities in commercial in vitro translation systems.
Protein arginine methylation is a well-known post-translational modification that has been shown to occur in rabbit reticulocyte in vitro translation lysates (RRL); however, it is not known whether this is a general feature of in vitro-produced proteins from other eukaryotic cell-free translation systems, particularly insect-derived lysates (ICL). Because methylation can affect protein localization, RNA binding and protein-protein interactions this may be of great importance as in vitro-produced proteins are often used in assays of protein function. Here, I report the presence of base-stable and base-labile methyltransferase activities in RRL, ICL and wheat germ in vitro extracts (WGE). Indeed, the presence of CARM1 in RRL and ICL and a class II protein arginine methyltransferase activity (PRMT5/7) is documented in all three systems. Additionally, the lysine methyltransferase that modifies eukaryotic elongation factor 1A (eEF-1A) was detected in ICL and WGE. Importantly, using a defined set of substrates under identical conditions I show that all three in vitro systems contain different complements of the various methyltransferases. These data suggest that three systems can be used in a complementary fashion to investigate the effect(s) of post-translational modification on protein function.
Denman
Robert B
RB
Biochemical Molecular Neurobiology Laboratory, Department of Molecular Biology, New York State Institute for Basic Research, In Developmental Disabilities, 1050 Forest Hill Road, Staten Island, NY 10314, USA. rbdenman@yahoo.com
D000595:Amino Acid Sequence; D000818:Animals; D002457:Cell Extracts; D002474:Cell-Free System; D051860:Fragile X Messenger Ribonucleoprotein 1 / Q000378:metabolism; D011495:Histone-Lysine N-Methyltransferase / Q000378:metabolism; D006657:Histones / Q000378:metabolism; D007313:Insecta / Q000201:enzymology; D008745:Methylation; D008969:Molecular Sequence Data; D004676:Myelin Basic Protein / Q000378:metabolism; D020648:Peptide Elongation Factor 1 / Q000378:metabolism; D014176:Protein Biosynthesis; D011496:Protein Methyltransferases / Q000378:metabolism*; D011499:Protein Processing, Post-Translational; D011484:Protein-Arginine N-Methyltransferases / Q000737:chemistry / Q000378:metabolism*; D011817:Rabbits; D017386:Sequence Homology, Amino Acid
D002457:Cell Extracts; D051860:Fragile X Messenger Ribonucleoprotein 1; D011495:Histone-Lysine N-Methyltransferase; D006657:Histones; D004676:Myelin Basic Protein; D020648:Peptide Elongation Factor 1; D011496:Protein Methyltransferases; D011484:Protein-Arginine N-Methyltransferases