A new family of small (5 kDa) protein inhibitors of insect α‐amylases from seeds or sorghum (<i>Sorghum bicolor</i> (L) Moench) have sequence homologies with wheat γ‐purothionins

Bloch, Carlos; Richardson, Michael

doi:10.1016/0014-5793(91)80261-z

Cited by 213 publications

(148 citation statements)

References 25 publications

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“…It has been reported that some homologues of Pth-Stl are inhibitory towards insect a-amylases [7], although no actual data has been published. No such activity was detected for Pth-Stl either against the enzymes from three different insect species or against the human salivary enzyme, which suggests that inhibition of a-amylases is not a general property of the family and that previous reports of such a property for other members of the family should be re-examined.…”

Section: Discussionmentioning

confidence: 99%

Pseudothionin‐St1, a potato peptide active against potato pathogens

Moreno¹,

Segura²,

Garcı́a-Olmedo³

1994

European Journal of Biochemistry

125

101

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A 5‐kDa polypeptide, pseudothionin Solanum tuberosum 1(Pth‐St1), which was active against Clavibacter michiganensis subspecies sepedonicus, a bacterial pathogen of potatoes, has been purified from the buffer‐insoluble fraction of potato tubers by salt extraction and HPCL. Pth‐St1 was also active against other potato pathogens tested (Pseudomonas solanacearum and Fusarium solani). The N‐terminal amino acid sequence of this peptide was identical (except for a N/H substitution at position 2) to that deduced from a previously reported cDNA sequence (EMBL accession number X‐13180), which had been misclassified as a Bowman‐Birk protease inhibitor. Pth‐St1 did not inhibit either trypsin or insect α‐amylase activities, and, in contrast with true thionins, did not affect cell‐free protein synthesis or β‐glucuronidase activity. Northern‐blot and tissue‐print analyses showed that steady‐state mRNA levels were highest in flowers (especially in petals), followed by tubers (especially in the epidermal cell layers and in leaf primordia), stems and leaves. Infection of leaves with a bacterial pathogen suspended in 10 mM MgCl2 switched off the gene, whereas mock inoculation with 10 mM MgCl2 alone induced higher mRNA levels.

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Section: Discussionmentioning

confidence: 99%

Pseudothionin‐St1, a potato peptide active against potato pathogens

Moreno¹,

Segura²,

Garcı́a-Olmedo³

1994

European Journal of Biochemistry

125

101

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“…6), while SInl has a very faint inhibitory effect [18]. Furthermore, no inhibitory effect on porcine pancreas a-amylase of both ohordothionin (data not shown) and SIal thionin [18] was detected. In contrast, y-hordothionin clearly inhibited the human saliva a-amylase, while a-hordothionin and P-hordothionin, as well as w-hordothionin, also failed to show any inhibitory effect.…”

Section: W-hmentioning

confidence: 83%

“…Thus, cu-hordothionin displays no inhibitory effect on human saliva a-amylase (Fig. 6), while SInl has a very faint inhibitory effect [18]. Furthermore, no inhibitory effect on porcine pancreas a-amylase of both ohordothionin (data not shown) and SIal thionin [18] was detected.…”

Section: W-hmentioning

confidence: 85%

“…Although these y-thionins possess inhibitory activity in vitro against protein synthesis in different cell-free systems 1121, their mode of action is unknown. Several structurally related polypeptides exhibiting sequence identity, including the three sorghum STal, 2 and 3 a-amylase inhibitors [18], two antifungal plant antifungal proteins from radish (RS-AFPI) and two polypeptides from radish [19], a new family of antifungal RS-AFPlike polypeptides from Brassicaceae [20] and the flower-specific thionin (FST) from tobacco cDNA [21], have been also described.…”

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confidence: 99%

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Primary Structure of ω‐Hordothionin, a Member of a Novel Family of Thionins from Barley Endosperm, and Its Inhibition of Protein Synthesis in Eukaryotic and Prokaryotic Cell‐Free Systems

Méndez

Rocher

Calero

et al. 1996

European Journal of Biochemistry

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A new sulfur-rich basic polypeptide, so called ru-hordothionin, has been isolated from barley endosperm by extractions with NaCl and ammonium bicarbonate followed by reverse-phase high performance liquid chromatography. Purified o-hordothionin was found to be homogeneous by SDS/polyacrylamide gel electrophoresis, N-terminal amino-acid sequencing and electrospray-ionization mass spectrometric analysis. The complete primary structure of cu-hordothionin was determined by automatic degradation of the intact molecule and peptides obtained by proteolytic cleavage. cu-hordothionin consists of a single polypeptide chain of 48 amino acids with a molecular mass of 5508 Da deduced from its amino acid sequence, which fully coincides with the 5508.2 Da determined by electrospray-ionization mass spectrometry. The isolated polypeptide showed a characteristic composition with a high content of basic amino acids (five arginine residues, two lysine residues and six histidine residues) and eight cysteine residues, and has strong sequence identity (66 %) with the sorghum SIcrl a-amylase inhibitor. cu-hordothionin, like y-hordothionin, exhibited translation inhibitory activity on both eukaryotic cell-free systems from mammalian (rat liver and rabbit reticulocyte lysates) and prokaryotic cell-free systems (Escherichia coli). However, in contrast to y-hordothionin, w-hordothionin did not inhibit plant systems such as Triticurn aestivunz, Cucumis sativus, Vicia sativa and Hordeum vulgare. ;i-hordothionin also inhibited the a-amylase activity from human saliva, while w-hordothionin and the other different genetic variants of thionins, ahordothionin and [j-hordothionin, failed to show any inhibitory effect.Keywords: w-hordothionin; y-thionin; barley; a-amylase inhibitor.Thionins are basic and cysteine-rich low-molecular-mass polypeptides of about 5 kDa, prevalently found in the endosperm of several Gramineae such as wheat and barley (a and /? purothionins and hordothionins), as well as in a variety of plant species, including leaves and stems (e.g. viscotoxin, pyrularia). Although orally innocuous, the thionins are toxic to injected animals [ l , 21, some yeast strains [3, 41, bacterial [3, 51, animal and plant cells [6, 71, fungi [8, 91 and insect larvae [lo]. They modify membrane permeability in cultured mammalian cells [ I l l and inhibit in vitro protein synthesis in cell-free systems derived from wheat germ, rabbit reticulocytes and Artemiu [ 121. Despite the fact that thionins are all believed to play a role in the defense system of plants against pathogens, the role and precise functional relationship between these polypeptides is still unclear.Recently, we described a new family of thionins, named 1'-thionins of about 5 kDa, found in the endosperm of wheat [13] and barley 1121. The three-dimensional structure of two members of the y-thionin family, y,-hordothionin (y,-H) and y,-puro- In this paper, we report the complete amino acid sequence of a new basic and cysteine-rich polypeptide isolated from barley endosperm, which we h...

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“…[11][12][13] Proteins isolated from seeds of monocot and dicot are found be homologous to "y" thionins [14][15][16][17] or identified via the sequencing of cDNA clones.…”

Section: Imran World Journal Of Pharmaceutical Researchmentioning

confidence: 99%

Defensins: A Novel Approach to Use Plant Antimicrobial Peptides as an Alternative to Antibiotics

Imran¹

2017

WJPR

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Indiscriminate and irrational use of antibiotics has created an unprecedented challenge for human civilization due to microbes development of antimicrobial resistance. It is difficult to treat bacterial infection due to bacteria ability to develop resistance against antimicrobial agents. Antimicrobial agents are categorized according to their mechanism of action, i.e., interference with cell wall synthesis,

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A new family of small (5 kDa) protein inhibitors of insect α‐amylases from seeds or sorghum (Sorghum bicolor (L) Moench) have sequence homologies with wheat γ‐purothionins

Cited by 213 publications

References 25 publications

Pseudothionin‐St1, a potato peptide active against potato pathogens

Pseudothionin‐St1, a potato peptide active against potato pathogens

Primary Structure of ω‐Hordothionin, a Member of a Novel Family of Thionins from Barley Endosperm, and Its Inhibition of Protein Synthesis in Eukaryotic and Prokaryotic Cell‐Free Systems

Defensins: A Novel Approach to Use Plant Antimicrobial Peptides as an Alternative to Antibiotics

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