A Multigene Family of Trypsin/α-Amylase Inhibitors from Cereals

Crystal Structure of Barley Limit Dextrinase-Limit Dextrinase Inhibitor (LD-LDI) Complex Reveals Insights into Mechanism and Diversity of Cereal Type Inhibitors

“…The impressive conformational stability of LDI together with possibility for integration with redox regulatory networks provides a possible rationale for conservation of the structural scaffold of the CTIs through a divergent evolution of the individual protein subfamilies. The outcome of this is a multitude of roles played by CTIs in regulation of plant development as seen in the present study and for previously described defense mechanisms (53).…”

Differential in vitro and in vivo effect of barley cysteine and serine protease inhibitors on phytopathogenic microorganisms

“…These proteins had been previously characterized [5,17,32], and their role as insecticides and acaricides supported by in vitro assays against digestive proteases from insects and acari, and by in vivo assays using transformed plants expressing some of the cystatins and the BTI-CMe protein [10,11,[33][34][35][36]. However, their inhibitory capacity towards plant bacterial and fungal pathogens had been less characterized.…”

“…Then, they were classified as cysteine, Abbreviations: PhyCys, plant cystatins; ORF, open reading frame; EC 50 , effective concentration for 50% inhibition; BTI, barley trypsin inhibitor; CPI, cystatin protease inhibitor. serine, aspartic, and metalloprotease inhibitors [2], However, several homologous inhibitors are able to inhibit different kind of proteases and they are now classified in function of their sequence similarities and tridimensional structures [3], Two of the most abundant plant protease inhibitors are the cystatins, family 125, that are cysteine protease inhibitors, and the cereal trypsin/ a-amylase inhibitors, family 16 [4,5], Plant cystatins (PhyCys) are plant proteinaceous inhibitors of cysteine proteases of the papain CIA family integrated in an independent subfamily on the cystatin phylogenetic tree [6,7], The cystatin inhibitory mechanism is produced by a tight and reversible interaction with their target enzymes. It involves a tripartite wedge formed by the partially flexible N-terminus containing a glycine residue and two hairpin loops carrying a conserved QxVxG motif and a tryptophan residue, respectively.…”

“…On the other hand, the plant family of the cereal trypsin/ a-amylase inhibitors is formed by proteins that accumulate in the seed [5]. Their members can be classified as trypsin inhibitors, a-amylase inhibitors, and dual trypsin/a-amylase inhibitors [22].…”

A Review: Biological and Technological Functions of Barley Seed Pathogenesis-Related Proteins (PRs)

“…They are categorized according to their amino acid or nucleotide sequence. The main protease inhibitors present in barley seeds are the following: a bifunctional barley α-amylase/subtilisin inhibitor (BASI), chymotrypsin/subtilisin inhibitors 1 and 2 (CI-1 and CI-2), a barley Bowman-Birk type trypsin inhibitor (BBBI), a large group of inhibitors representing bifunctional α-amylase/trypsin inhibitors (CM proteins) and serpins 43,305 . Each family contains members differing in enzyme specificities 43,305 .…”