caa a22 4500 475766245 CHVBK 20180406123606.0 cr unu---uuuuu 170329e20001201xx s 000 0 eng 10.1007/s007050070004 doi (NATIONALLICENCE)springer-10.1007/s007050070004 Mutational analysis of the NIa protease from pepper vein banding potyvirus [Elektronische Daten] [J. Joseph, H. S. Savithri] Summary.:  The nuclear inclusion protein a (NIa) protease plays an important role in the life cycle of potyviruses by processing the viral polyprotein into functional proteins. For functional characterization, the NIa protease from Pepper vein banding potyvirus (PVBV) was overexpressed in Escherichia coli and purified. Using a recombinant polyprotein substrate containing the nuclear inclusion protein b (NIb)-coat protein (CP) cleavage site, a trans-cleavage assay was developed for the NIa protease. The polyprotein substrate also possessed the cleavage site between NIa and NIb, in addition to the NIb-CP site. However, no trans-cleavage by the NIa protease between NIa and NIb was detected indicating that the cleavage between NIa and NIb under natural conditions would be by a cis-cleavage reaction. Site-specific mutations of the conserved residues D81, D90, C110, T146, C151 and H167 were performed to investigate their roles in the catalytic process of the protease. Such an analysis has revealed that D81 and C151 constitute two of the catalytic triad residues in the NIa protease, D90 and C110 are not essential for catalysis, and T146 and H167 are probably involved in binding to Gln at the P1 position of the substrate. Springer-Verlag/Wien, 2000 Joseph J. Department of Biochemistry, Indian Institute of Science, Bangalore, India, IN aut Savithri H. S. Department of Biochemistry, Indian Institute of Science, Bangalore, India, IN aut https://doi.org/10.1007/s007050070004 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s007050070004 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Joseph J. Department of Biochemistry, Indian Institute of Science, Bangalore, India, IN aut NATIONALLICENCE 700 1- Savithri H. S. Department of Biochemistry, Indian Institute of Science, Bangalore, India, IN aut Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer