Further in vitro characterization of mouse hepatitis virus papain-like proteinase 1: cleavage sequence requirements within pp1a.
Proteolytic processing of the mouse hepatitis virus strain A59 (MHV-A59) replicase gene product, pp1a, results in polypeptides p28, p65, p50, and p240 in infected cells. Based on previously identified p28 and p65 cleavage sites, a p50 cleavage site was proposed to occur between Ala-1262 and Ala-1263. Results of mutagenesis and in vitro cleavage assays show that PLP-1 was able to cleave in trans when the proposed p50 cleavage sequence replaced the p28 cleavage sequence. Mutagenesis was also used to investigate cleavage between Gly-904 and Val-905, a cleavage site predicted to produce a precursor of p65, p72, that was detected in cells infected with MHV strain JHM, but not with MHV-A59. No cleavage could be detected using substrate that carried both the p65 site and the predicted p72 cleavage sequence. Thus, it appeared that PLP-1 could recognize the proposed p50 sequence but not the predicted p72 site under the in vitro conditions used.
Teng
Henry
H
Department of Microbiology, University of Pennsylvania School of Medicine, Philadelphia 19104-6076, USA.
Weiss
Susan R
SR
D020134:Catalytic Domain; D000086882:Coronavirus Papain-Like Proteases; D066298:In Vitro Techniques; D006517:Murine hepatitis virus / Q000235:genetics*; D016296:Mutagenesis; D016366:Open Reading Frames / Q000235:genetics; D010206:Papain / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*
D000086882:Coronavirus Papain-Like Proteases; D010206:Papain