Disease relevance of NIa-Pro

• Another signal corresponding to approximately 49 kDa was detected in disrupted, RNase-treated virions with anti-VPg antibodies but not with antibodies to NIa-Pro [1].
• NIaPro and two NIaPro-containing polyproteins (NIa and 6/NIa) were analyzed from extracts of recombinant Escherichia coli [2].
• Binding properties of P1, HC-Pro, CI and NIaPro are consistent with previous studies carried out on a few other potyviruses, but the binding of VPg, NIb and CP to RNA reveal novel interactions between RNA and potyvirus proteins [3].

High impact information on NIa-Pro

• In previous work, we have shown that the protease domain of the nuclear inclusion a protease (NIaPro) from PVY is the elicitor of the Ry-mediated resistance and that integrity of the protease active site is required for the elicitation of the resistance response [4].
• To resolve these possibilities, the NIaPro from PVY was randomly mutagenised and the clones obtained were screened for elicitation of cell death as an indicator of resistance and proteolytic activity [4].
• Eighteen recombination sites were found spaced throughout the 5' two-thirds of the genome, but there were only two in the 3' one-third; thus, 24 and 35 % of the P1 and NIa-VPg gene sequences examined were recombinants, whereas only 1 % of the corresponding NIa-Pro and CP gene sequences were recombinants [5].
• The results of this study indicate that NIaPro catalyses proteolytic cleavages preferentially in cis, and that the 6K1/CI and NIb/CP sites can also be processed in trans [6].
• The sites at the P3/6K1, CI-6K2 and VPg/NIaPro junctions were processed slowly, in contrast to other proteolytic cleavage sites which were processed at a high rate [6].

Biological context of NIa-Pro

• Both 6K peptides are indispensable for virus replication, and proteolytic separation of the 6K2 protein from the adjacent proteins by NIaPro is important for the rate of virus replication and movement [6].

Associations of NIa-Pro with chemical compounds

• Their sequences agree with consensus potyviral NIa-Pro cleavage sequences except for that at the 6K-VPg site, which is characterized by a glutamic acid residue preceding the hydrolysed peptide bond [7].

References