Structural insights into the unique inhibitory mechanism of Kunitz type trypsin inhibitor from Cicer arietinum L.

TitleStructural insights into the unique inhibitory mechanism of Kunitz type trypsin inhibitor from Cicer arietinum L.
Publication TypeJournal Article
Year of Publication2018
AuthorsBendre, AD, Suresh, CG, Shanmugam, D, Ramasamy, S
JournalJournal of Biomolecular Structure and Dynamics
Volume24
Pagination1-9
Date PublishedNOV
Type of ArticleArticle
AbstractKunitz-type trypsin inhibitors bind to the active pocket of trypsin causing its inhibition. Plant Kunitz-type inhibitors are thought to be important in defense, especially against insect pests. From sequence analysis of various Kunitz-type inhibitors from plants, we identified CaTI2 from chickpea as a unique variant lacking the functionally important arginine residue corresponding to the soybean trypsin inhibitor (STI) and having a distinct and unique inhibitory loop organization. To further explore the implications of these sequence variations, we obtained the crystal structure of recombinant CaTI2 at 2.8Å resolution. It is evident from the structure that the variations in the inhibitory loop facilitates non-substrate like binding of CaTI2 to trypsin, while the canonical inhibitor STI binds to trypsin in substrate like manner. Our results establish the unique mechanism of trypsin inhibition by CaTI2, which warrant further research into its substrate spectrum. Abbreviations BApNA Nα-Benzoyl-L-arginine 4-nitroanilide BPT bovine pancreatic trypsin CaTI2 Cicer arietinum L trypsin inhibitor 2 DrTI Delonix regia Trypsin inhibitor EcTI Enterolobium contortisiliquum trypsin inhibitor ETI Erythrina caffra trypsin inhibitor KTI Kunitz type inhibitor STI soybean trypsin inhibitor TKI Tamarindus indica Kunitz inhibitor Communicated By Ramaswamy H. Sarma.
Type of Journal (Indian or Foreign)Foreign
Impact Factor (IF)3.107
Divison category: 
Biochemical Sciences

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