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Phage display selection can differentiate insecticidal activity of soybean cystatins
Author(s) -
Koiwa Hisashi,
Shade Richard E.,
ZhuSalzman Keyan,
Subramanian Lalitha,
Murdock Larry L.,
Nielsen S. Suzanne,
Bressan Ray A.,
Hasegawa Paul M.
Publication year - 1998
Publication title -
the plant journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.058
H-Index - 269
eISSN - 1365-313X
pISSN - 0960-7412
DOI - 10.1046/j.1365-313x.1998.00119.x
Subject(s) - biopanning , biology , papain , phage display , callosobruchus maculatus , vicilin , cystatin , recombinant dna , bacillus thuringiensis , bioassay , biochemistry , gene , peptide sequence , genetics , storage protein , botany , peptide library , pest analysis , bacteria , enzyme , peptide , renal function , cystatin c
Summary Plant cysteine proteinase inhibitors (phytocystatins) have been implicated as defensive molecules against Coleopteran and Hemipteran insect pests. Two soybean cystatins, soyacystatin N (scN) and soyacystatin L (scL), have 70% sequence identity but scN is a much more potent inhibitor of papain, vicilin peptidohydrolase and insect gut proteinases. When these cystatins were displayed on phage particles, papain‐binding affinity and CPI activity of scN were substantially greater than those of scL, in direct correlation with their relative CPI activity as soluble recombinant proteins. Furthermore, scN substantially delayed cowpea weevil ( Callosobruchus maculatus (F.)) growth and development in insect feeding bioassays, whereas scL was essentially inactive as an insecticide. Papain biopanning selection of phage‐displayed soyacystatins resulted in a 200–1000‐fold greater enrichment for scN relative to scL. These results establish that binding affinity of cystatins can be used in phage display biopanning procedures to select variants with greater insecticidal activity, illustrating the potential of phage display and biopanning selection for directed molecular evolution of biological activity of these plant defensive proteins.