3i74
Crystal Structure of the plant subtilisin-like protease SBT3 in complex with a chloromethylketone inhibitor
Structural highlights
FunctionSBT3_SOLLC Serine protease (PubMed:19332543, PubMed:19407393, PubMed:19805099, PubMed:27259555, PubMed:27451395). Has preference for Gln in the P1 position and Lys in the P2 position of oligopeptide substrates. Active also with His in the P1 position (PubMed:19332543). Involved in resistance against insects partly by regulating expression of systemic wound response genes and possibly by its post-ingestive activity in the insect gut. Apart from the role in defense, may be involved in regulation of pectin methylesterases (PMEs) activity and pectin methylesterification of the cell wall (PubMed:27259555).[1] [2] [3] [4] [5] Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedSubtilases 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. Structural 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 Proc Natl Acad Sci U S A. 2009 Oct 6;106(40):17223-8. Epub 2009 Sep 23. PMID:19805099[6] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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