2LQX

NMR spatial structure of the trypsin inhibitor BWI-2c from the buckwheat seeds

Summary for 2LQX

• Entry DOI: 10.2210/pdb2lqx/pdb
• NMR Information: BMRB: 18334
• Descriptor: Trypsin inhibitor BWI-2c (1 entity in total)
• Functional Keywords: helical hairpin, hydrolase inhibitor
• Biological source: Fagopyrum esculentum
• Total number of polymer chains: 1
• Total formula weight: 5196.94

Authors

Mineev, K.S.,Vassilevski, A.A.,Oparin, P.B.,Grishin, E.V.,Egorov, T.A. (deposition date: 2012-03-19, release date: 2012-05-30, Last modification date: 2023-06-14)

Primary citation

Oparin, P.B.,Mineev, K.S.,Dunaevsky, Y.E.,Arseniev, A.S.,Belozersky, M.A.,Grishin, E.V.,Egorov, T.A.,Vassilevski, A.A.
Buckwheat trypsin inhibitor with helical hairpin structure belongs to a new family of plant defence peptides.
Biochem.J., 446:69-77, 2012

PubMed Abstract: A new peptide trypsin inhibitor named BWI-2c was obtained from buckwheat (Fagopyrum esculentum) seeds by sequential affinity, ion exchange and reversed-phase chromatography. The peptide was sequenced and found to contain 41 amino acid residues, with four cysteine residues involved in two intramolecular disulfide bonds. Recombinant BWI-2c identical to the natural peptide was produced in Escherichia coli in a form of a cleavable fusion with thioredoxin. The 3D (three-dimensional) structure of the peptide in solution was determined by NMR spectroscopy, revealing two antiparallel α-helices stapled by disulfide bonds. Together with VhTI, a trypsin inhibitor from veronica (Veronica hederifolia), BWI-2c represents a new family of protease inhibitors with an unusual α-helical hairpin fold. The linker sequence between the helices represents the so-called trypsin inhibitory loop responsible for direct binding to the active site of the enzyme that cleaves BWI-2c at the functionally important residue Arg(19). The inhibition constant was determined for BWI-2c against trypsin (1.7×10(-1)0 M), and the peptide was tested on other enzymes, including those from various insect digestive systems, revealing high selectivity to trypsin-like proteases. Structural similarity shared by BWI-2c, VhTI and several other plant defence peptides leads to the acknowledgement of a new widespread family of plant peptides termed α-hairpinins.

PubMed: 22612157
DOI: 10.1042/BJ20120548

Experimental method

SOLUTION NMR