title: Photoaffinity labeling with GTP of viral p21 ras protein expressed in Escherichia coli.
abstract: The v-ras oncogene of Harvey murine sarcoma virus encodes a 21,000-dalton protein, p21, which mediates transformation produced by that virus. Previous work has shown that both p21v-rasH and the cellular homolog p21c-rasH appear to bind guanine nucleotides. We report here the expression in Escherichia coli of v-rasH to produce a biochemically active p21 fusion protein which retains both guanine nucleotide binding and autophosphorylating activity. Furthermore, direct interaction of this protein with GTP is unequivocally demonstrated by photoaffinity labeling it with [alpha-32P]GTP.
mesh_terms: D000345:Affinity Labels / Q000378:metabolism*; D000595:Amino Acid Sequence; D001483:Base Sequence; D003001:Cloning, Molecular; D004262:DNA Restriction Enzymes; D004926:Escherichia coli / Q000235:genetics*; D005814:Genes, Viral; D006160:Guanosine Triphosphate / Q000378:metabolism*; D006251:Harvey murine sarcoma virus / Q000235:genetics*; D008970:Molecular Weight; D015689:Oncogene Protein p21(ras); D009857:Oncogenes; D010761:Phosphorus Radioisotopes; D010957:Plasmids; D009053:Sarcoma Viruses, Murine / Q000235:genetics*; D014764:Viral Proteins / Q000235:genetics* / Q000302:isolation & purification
chemical_list: D000345:Affinity Labels; D010761:Phosphorus Radioisotopes; D014764:Viral Proteins; D006160:Guanosine Triphosphate; D004262:DNA Restriction Enzymes; D015689:Oncogene Protein p21(ras)