Download MendeleyStructural basis for Ca2+-independence and activation by homodimerization of tomato subtilase 3.
Ottmann, C., Rose, R., Huttenlocher, F., Cedzich, A., Hauske, P., Kaiser, M., Huber, R., Schaller, A.(2009) Proc Natl Acad Sci U S A 106: 17223-17228
- PubMed: 19805099
- DOI: https://doi.org/10.1073/pnas.0907587106
- Primary Citation of Related Structures:
3I6S, 3I74 - PubMed Abstract:
Subtilases are serine proteases found in Archae, Bacteria, yeasts, and higher eukaryotes. Plants possess many more of these subtilisin-like endopeptidases than animals, e.g., 56 identified genes in Arabidopsis compared with only 9 in humans, indicating important roles for subtilases in plant biology. We report the first structure of a plant subtilase, SBT3 from tomato, in the active apo form and complexed with a chloromethylketone (cmk) inhibitor. The domain architecture comprises an N-terminal protease domain displaying a 132 aa protease-associated (PA) domain insertion and a C-terminal seven-stranded jelly-roll fibronectin (Fn) III-like domain. We present the first structural evidence for an explicit function of PA domains in proteases revealing a vital role in the homo-dimerization of SBT3 and in enzyme activation. Although Ca(2+)-binding sites are conserved and critical for stability in other subtilases, SBT3 was found to be Ca(2+)-free and its thermo stability is Ca(2+)-independent.
Organizational Affiliation:
Chemical Genomics Centre, Otto-Hahn-Strasse 15, 44227 Dortmund, Germany.
