An atypical aspartic protease modulates lateral root development in Arabidopsis thaliana

We determined the specificity profile of recombinant ASPR1 (Atypical Aspartic Protease in Roots 1) using proteome-derived libraries. Although rASPR1 preferred hydrophobic amino acids in the S1 subsite, which is in line with what was previously described for other APs, rASPR1 also displayed a clear preference for accommodating asparagine and lysine in S1, a characteristic only reported so far for fungal APs. Both primary and secondary specificity preferences of rASPR1 thus revealed unique specificity requirements similar to fungal APs that are unprecedented for plant APs.