title: WCI, a novel wheat chymotrypsin inhibitor: purification, primary structure, inhibitory properties and heterologous expression.
abstract: A novel chymotrypsin inhibitor, detected in the endosperm of Triticum aestivum, was purified and characterized with respect to the main physical-chemical properties. On the basis of its specificity, this inhibitor was named WCI (wheat chymotrypsin inhibitor). WCI is a monomeric neutral protein made up of 119 residues and molecular mass value of 12,933.40 Da. Automated sequence and mass spectrometry analyses, carried out on several samples of purified inhibitor, evidenced an intrinsic molecular heterogeneity due to the presence of the isoform [des-(Thr)WCI], accounting for about 40% of the total sample. In vitro, WCI acted as a strong inhibitor of bovine pancreatic chymotrypsin as well as of chymotryptic-like activities isolated from the midgut of two phytophagous insects, Helicoverpa armigera (Hüb.) and Tenebrio molitor L., respectively. No inhibitory activities were detected against bacterial subtilisins, bovine pancreatic trypsin, porcine pancreatic elastase or human leukocyte elastase. The primary structure of WCI was significantly similar (45.7-89.1%) to those of several proteins belonging to the cereal trypsin/α-amylase inhibitor super-family and showed the typical sequence motif of this crowed protein group. The cDNA of the inhibitor (wci-cDNA) was isolated from wheat immature caryopses and employed to obtain a recombinant product in E. coli. Experimental evidences indicated that the recombinant inhibitor was localized in the inclusion bodies from which it was recovered as soluble and partially active protein by applying an appropriate refolding procedure. WCI reactive site localization, as well as its inhibitory specificity, was investigated by molecular modeling approach.
authors: Dipartimento di Scienze della Vita, Seconda Università degli Studi di Napoli, 81100 Caserta, Italy.
authors: Antimo
authors: A
authors: Di Maro
authors: Francesca
authors: F
authors: Farisei
authors: Daniela
authors: D
authors: Panichi
authors: Valeria
authors: V
authors: Severino
authors: Natalia
authors: N
authors: Bruni
authors: Anna Grazia
authors: AG
authors: Ficca
authors: Pasquale
authors: P
authors: Ferranti
authors: Valeria
authors: V
authors: Capuzzi
authors: Francesca
authors: F
authors: Tedeschi
authors: Elia
authors: E
authors: Poerio
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