5XOZ

Crystal structure of a Kunitz type trypsin inhibitor from Cicer arietinumL

Summary for 5XOZ

• Entry DOI: 10.2210/pdb5xoz/pdb
• Descriptor: Trypsin protein inhibitor 2 (1 entity in total)
• Functional Keywords: kunitz, inhibitor, beta-trefoil, hydrolase inhibitor
• Biological source: Cicer arietinum (Chickpea)
• Total number of polymer chains: 2
• Total formula weight: 48810.68

Authors

Bendre, A.D.,Suresh, C.G.,Ramasamy, S. (deposition date: 2017-05-31, release date: 2018-06-20, Last modification date: 2024-11-13)

Primary citation

Bendre, A.D.,Suresh, C.G.,Shanmugam, D.,Ramasamy, S.
Structural insights into the unique inhibitory mechanism of Kunitz type trypsin inhibitor from Cicer arietinum L.
J.Biomol.Struct.Dyn., 37:2669-2677, 2019

PubMed Abstract: Kunitz-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.

PubMed: 30052127
DOI: 10.1080/07391102.2018.1494633

Experimental method

X-RAY DIFFRACTION (2.8 Å)