Enzyme Inhibitors of Seeds: Types and Properties

Shewry, Peter R.

doi:10.1007/978-94-011-4431-5_25

Cited by 27 publications

(28 citation statements)

References 137 publications

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“…The manner in which PawS1 has evolved a trypsin-inhibitory peptide for its PDP region within the Helianthinae subtribe implies natural selection has also played a role in the origin of the trypsin-inhibitory function. Seed protease inhibitors are thought to provide protection from gramnivores (Shewry, 1999), with some Ser protease inhibitors demonstrated to protect plants from insects (Dunse et al, 2010;Hartl et al, 2010). The age of the PDP family and the appearance of the protease inhibitory motif independently in plant and animal kingdoms suggests the trypsin-inhibitory biochemical function arose by convergent exploration of sequence space under the relaxed selection permitted by albumin.…”

Section: Discussionmentioning

confidence: 99%

“…The PDP region appears hypervariable relative to the major subunits of the adjacent napin-type albumin (Supplemental Figure 5). These albumins typically vary greatly between species with the main conserved features being an ER targeting signal sequence, richness in Gln, and eight conserved Cys residues (Shewry, 1999). Sunflower contains at least six highly variable albumin-coding genes Ha-G5 (Allen et al, 1987), Ha-BA1, SUNFLOWER ALBUMIN8 (SFA8) (Kortt et al, 1991), and pHAO (Thoyts et al, 1996), along with PawS1 and PawS2 (Mylne et al, 2011).…”

Section: Within Paws1 Genes Both the Pdp And Albumin Regions Are Evomentioning

confidence: 99%

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Evolutionary Origins of a Bioactive Peptide Buried within Preproalbumin

et al. 2014

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The de novo evolution of proteins is now considered a frequented route for biological innovation, but the genetic and biochemical processes that lead to each newly created protein are often poorly documented. The common sunflower (Helianthus annuus) contains the unusual gene PawS1 (Preproalbumin with SFTI-1) that encodes a precursor for seed storage albumin; however, in a region usually discarded during albumin maturation, its sequence is matured into SFTI-1, a protease-inhibiting cyclic peptide with a motif homologous to unrelated inhibitors from legumes, cereals, and frogs. To understand how PawS1 acquired this additional peptide with novel biochemical functionality, we cloned PawS1 genes and showed that this dual destiny is over 18 million years old. This new family of mostly backbone-cyclic peptides is structurally diverse, but the protease-inhibitory motif was restricted to peptides from sunflower and close relatives from its subtribe. We describe a widely distributed, potential evolutionary intermediate PawS-Like1 (PawL1), which is matured into storage albumin, but makes no stable peptide despite possessing residues essential for processing and cyclization from within PawS1. Using sequences we cloned, we retrodict the likely stepwise creation of PawS1's additional destiny within a simple albumin precursor. We propose that relaxed selection enabled SFTI-1 to evolve its inhibitor function by converging upon a successful sequence and structure.

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Section: Discussionmentioning

confidence: 99%

Section: Within Paws1 Genes Both the Pdp And Albumin Regions Are Evomentioning

confidence: 99%

Evolutionary Origins of a Bioactive Peptide Buried within Preproalbumin

et al. 2014

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“…Some inhibit amylases, while others are bi-functional inhibitors that act both on proteases and amylases (reviewed by Shewry 1999). One representative of this group is a barley protein of 19.8 kDa that inhibits a-amylase and the protease subtilisin (Svendsen et al 1986).…”

Section: Introductionmentioning

confidence: 98%

Structural diversity and organization of three gene families for Kunitz-type enzyme inhibitors from potato tubers ( Solanum tuberosum L.)

Heibges¹,

Glaczinski²,

Ballvora³

et al. 2003

Mol Gen Genomics

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In the potato, Kunitz-type enzyme inhibitors are abundant and highly polymorphic small proteins found in tubers. DNA sequence analysis of 1596 unselected ESTs (expressed sequence tags) from mature tubers of the cultivars Provita and Saturna resulted in the identification of 55 different DNA sequences with high sequence similarity to Kunitz-type enzyme inhibitors. The frequency of Kunitz-type inhibitor ESTs in Provita was four times higher than in Saturna tubers, and none of the Provita ESTs was identical to any of the Saturna ESTs. A phenogram constructed from the deduced amino acid sequences of the inhibitors revealed three major homology groups-A, B and C. Group A inhibitors were all derived from Provita ESTs. Inhibitor groups A and B were more similar to each other than to group C inhibitors, and for most members within-group similarity was at least 90%. Non-conservative amino acid substitutions and insertion/deletion polymorphisms suggest functional differentiation between members of the gene family. A minimum of 21 genes for Kunitz-type enzyme inhibitors (six for group A, nine for group B and six for group C) was estimated to exist in the potato genome. Genetic mapping and the identification of BAC (bacterial artificial chromosome) clones containing more than one member of the gene family indicated that most inhibitor genes of groups A, B and C are organized in a cluster that maps to a single region on potato chromosome III.

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“…Kunitz-type enzyme inhibitors are a highly polymorphic and abundant class of plant proteins with multiple functions as enzyme inhibitors (Shewry 1999), storage proteins (Kortt et al 1989) or agents of defence against pathogens or insects (Boulter 1993;Schuler et al 1998).…”

Section: Introductionmentioning

confidence: 99%

Functional comparison of homologous members of three groups of Kunitz-type enzyme inhibitors from potato tubers ( Solanum tuberosum L.)

Heibges¹,

Salamini²,

Gebhardt³

2003

Mol Gen Genomics

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For functional studies, nine cDNAs encoding Kunitz-type enzyme inhibitors from potato tubers were expressed as GST (glutathione S transferase)-tagged fusion proteins in the fission yeast Schizosaccharomyces pombe. The inhibitors represented the three major homology groups A, B and C found in tubers. Members of the same homology group were at least 90% identical in sequence. The purified GST fusion proteins were tested for their ability to inhibit the proteases trypsin, alpha-chymotrypsin, subtilisin, papain and aspergillopepsin I, and for inhibition of the growth of fungi. Fusion proteins belonging to the same and different homology groups were found to exhibit distinct protease inhibition profiles. Removal of the GST tag by cleavage with enterokinase did not change the inhibition profile but increased the inhibitory activity. Group A and B inhibitors affected the proteases to different extents, whereas group C inhibitors showed only weak or no protease inhibition. One fusion protein completely inhibited aspergillopepsin I. One fusion protein each of groups A and B strongly inhibited mycelial growth of the fungus Fusarium moniliforme. The results suggest functional polymorphism among closely related members of the Kunitz-type inhibitor family.

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Enzyme Inhibitors of Seeds: Types and Properties

Cited by 27 publications

References 137 publications

Evolutionary Origins of a Bioactive Peptide Buried within Preproalbumin

Evolutionary Origins of a Bioactive Peptide Buried within Preproalbumin

Structural diversity and organization of three gene families for Kunitz-type enzyme inhibitors from potato tubers ( Solanum tuberosum L.)

Functional comparison of homologous members of three groups of Kunitz-type enzyme inhibitors from potato tubers ( Solanum tuberosum L.)

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