title: Polyoma virus major capsid protein, VP1. Purification after high level expression in Escherichia coli.
abstract: We have expression-cloned in Escherichia coli the major polyoma virus capsid protein, VP1. Under the inducible control of the hybrid tac promoter, VP1 constituted between 2 and 3% of the total host cell protein. The expressed VP1 was purified to near homogeneity with initial yields to 10%. Optimal expression was temperature-dependent, and significant intracellular degradation could be demonstrated. The final product was obtained as one predominant isoelectric focusing species, without the pattern of post-translational modification seen in virus-infected eukaryotic cells. The purified VP1 from E. coli will be useful as a substrate for the purification of VP1 modification enzymes and in the study of inter-VP1 oligomerization.
mesh_terms: D003001:Cloning, Molecular; D004262:DNA Restriction Enzymes; D004591:Electrophoresis, Polyacrylamide Gel; D004926:Escherichia coli / Q000235:genetics*; D005590:Fractional Precipitation; D007163:Immunosorbent Techniques; D007525:Isoelectric Focusing; D008970:Molecular Weight; D010957:Plasmids; D011120:Polyomavirus / Q000235:genetics*; D011401:Promoter Regions, Genetic; D014158:Transcription, Genetic; D014764:Viral Proteins / Q000235:genetics* / Q000302:isolation & purification; D015678:Viral Structural Proteins
chemical_list: D014764:Viral Proteins; D015678:Viral Structural Proteins; D004262:DNA Restriction Enzymes