Sequence determination by MALDI-TOF mass spectrometry of an insecticidal lentil peptide of the PA1b type. (June 2015)

• Record Type: Journal Article
• Authors: Taylor, Wesley G.; Sutherland, Daniel H.; Zhang, Haixia; Hegedus, Dwayne D.
• Is Part Of: Phytochemistry letters. Volume 12(2015:Jun.)
• Page Start: 105
• Page End: 112
• Publication Date: 2015-06
• Subjects: Lens culinaris -- Lentils -- Seed albumin -- PA1b peptide -- Mass spectrometry -- Proteases -- Ladder sequencing; Botanical chemistry -- Periodicals; Chimie végétale -- Périodiques; 572.205
• DOI: 10.1016/j.phytol.2015.03.003
• Languages: English
• ISSNs: 1874-3900

Abstract

Graphical abstract: Highlights: Lentil ( Lens culinaris Medik.) seeds contain an insecticidal peptide. Insecticidal lentil peptide (ILP) was purified and the amino acid sequence determined. ILP was similar to pea PA1b peptide and to soybean leginsulin. L. culinaris genomic DNA information confirmed the ILP sequence. Abstract: Mature seeds of lentil ( Lens culinaris Medik.) were previously reported to contain an insecticidal cysteine-rich peptide, likely of the albumin-1 subunit b type. The purpose of this work was to determine the amino acid sequence of this insecticidal lentil peptide in an Eston lentil extract by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS), after reduction of the disulfide bridges, alkylation of the cysteine residues and hydrolysis by pronase, trypsin, chymotrypsin and endoproteinase Asp-N. Sequences of key fragments were supported by monoisotopic mass measurements and by sequence ions from collision-induced dissociation (CID) experiments with a MALDI-TOF/TOF analyzer (MS/MS analysis). The new 37 amino acid sequence revealed strong similarities to a histidine-containing pea PA1b peptide and to soybean leginsulins but with a unique segment of RSSA in the middle. The lentil PA1b peptide sequence agreed completely with that derived from a L. culinaris genomic DNA sequence.