Yoshioka K, Kanda H, Kondo S, Togashi S, Miyake T, Shiba T
Laboratory of Molecular Biology, School of Hygienic Sciences, Kitasato University, Kanagawa, Japan.
FEBS Lett. 1991 Jul 8;285(1):31-4. doi: 10.1016/0014-5793(91)80718-i.
Drosophila copia protease is likely to be encoded in the gag gene. We have expressed copia gag polyprotein precursor in E. coli. The gag precursor was correctly processed to generate a unique laminate structure in E. coli. The processing was almost completely blocked by a mutation at the putative active site of copia protease, and resulted in accumulation of the precursor. Furthermore, the laminate structure was not found in E. coli expressing the mutant precursor. These results indicate that the protease is involved in cleaving the gag precursor itself. Also, the assembly of copia gag protein should correlate to the autoprocessing of copia gag polyprotein precursor.
果蝇copia蛋白酶可能由gag基因编码。我们已在大肠杆菌中表达了copia gag多蛋白前体。gag前体在大肠杆菌中被正确加工，产生了独特的层状结构。在copia蛋白酶假定的活性位点发生突变后，加工过程几乎完全受阻，导致前体积累。此外，在表达突变前体的大肠杆菌中未发现层状结构。这些结果表明，该蛋白酶参与切割gag前体本身。而且，copia gag蛋白的组装应与copia gag多蛋白前体的自身加工相关。
