Novel antifungal α-hairpinin peptide from Stellaria media seeds: structure, biosynthesis, gene structure and evolution.

Plant defense against disease is a complex multistage system involving initial recognition of the invading pathogen, signal transduction and activation of specialized genes. An important role in pathogen deterrence belongs to so-called plant defense peptides, small polypeptide molecules that present antimicrobial properties. Using multidimensional liquid chromatography, we isolated a novel antifungal peptide named Sm-AMP-X (33 residues) from the common chickweed (Stellaria media) seeds.

Isolation, molecular cloning and antimicrobial activity of novel defensins from common chickweed (Stellaria media L.) seeds.

Two novel highly homologous defensins, Sm-AMP-D1 and Sm-AMP-D2, were isolated from seeds of common chickweed Stellaria media L. (family Cariophyllaceae). They show sequence homology to defensins of the Brassicaceae plants and display strong inhibitory activity against phytopathogenic fungi and oomycetes in the micromolar range (IC(50)≤1μM).

Antifungal activity of storage 2S albumins from seeds of the invasive weed dandelion Taraxacum officinale Wigg.

In this work, we isolated and characterized novel antifungal proteins from seeds of dandelion (Taraxacum officinale Wigg.). We showed that they are represented by five isoforms, each consisting of two disulphide-bonded large and small subunits.

A novel antifungal hevein-type peptide from Triticum kiharae seeds with a unique 10-cysteine motif.

Two forms of a novel antimicrobial peptide (AMP), named WAMP-1a and WAMP-1b, that differ by a single C-terminal amino acid residue and belong to a new structural type of plant AMP were purified from seeds of Triticum kiharae Dorof. et Migusch. Although WAMP-1a and WAMP-1b share similarity with hevein-type peptides, they possess 10 cysteine residues arranged in a unique cysteine motif which is distinct from those described previously for plant AMPs, but is characteristic of the chitin-binding domains of cereal class I chitinases.

Seed defensins of barnyard grass Echinochloa crusgalli (L.) Beauv.

From the annual weed barnyard grass Echinochloa crusgalli (L.) Beauv., two novel defensins Ec-AMP-D1 and Ec-AMP-D2 that differ by a single amino acid substitution were isolated by a combination of different chromatographic procedures.

Seed defensins from T. kiharae and related species: genome localization of defensin-encoding genes.

Ten new defensins have been isolated from seeds of Triticum kiharae and related species of the Triticum and Aegilops genera by a combination of chromatographic procedures including affinity-, size-exclusion, and reversed-phase high-performance liquid chromatography. Nine were completely sequenced and shown to represent a family of closely related peptides with highly conserved amino acid sequences. Analysis of defensin compositions in diploid A-, B-, and D-genome donors to polyploid wheat allowed us for the first time to assign most defensin-encoding genes to particular hexaploid wheat genomes.

New protease inhibitors from buckwheat seeds: properties, partial amino acid sequences and possible biological role.

Preparations of new low molecular weight protein inhibitors of serine proteinases have been obtained from buckwheat Fagopyrum esculentum seeds by chromatography of seed extracts on trypsin-Sepharose 4B, Mono-Q and Mono-S ion-exchangers. Their molecular masses, determined by mass spectrometry, were equal to 5203 (BWI-1c), 5347 (BWI-2c), 7760 (BWI-3c) and 6031 daltons (BWI-4c). All inhibitors possessed high pH-stability in the pH range 2-12 and thermostability.

De novo sequencing of antimicrobial peptides isolated from the venom glands of the wolf spider Lycosa singoriensis.

Antimicrobial peptides (AMPs), named lycocitin 1, 2 and 3, and a peptide with a monoisotopic molecular mass of 3038.70 Da were detected in the venom glands of the wolf spider Lycosa singoriensis. Two of the peptides, lycocitin 1 and 2, are new AMPs whereas lycocitin 3 is highly homologous to lycotoxin II isolated from the venom of spider Lycosa carolinensis.

Cationic inhibitors of serine proteinases from buckwheat seeds.

Preparations of low molecular weight protein inhibitors of serine proteinases have been obtained from buckwheat (Fagopyrum esculentum) seeds by chromatography of seed extract on trypsin-Sepharose 4B, Mono-Q, and Mono-S ion exchangers (FPLC regime). Their molecular masses, determined by mass spectrometry, were 5203 (BWI-1c), 5347 (BWI-2c), 7760 (BWI-3c), and 6031 daltons (BWI-4c). All of the inhibitors possess high pH- and thermal stability in the pH range 2-12.

Complete amino acid sequence of the protease inhibitor BWI-4a from buckwheat seeds.

The complete amino acid sequence of the protease inhibitor BWI-4a from buckwheat (Fagopyrum esculentum Moench) seeds has been established by automated Edman degradation in combination with MALDI-TOF mass spectrometry. The inhibitor molecule consists of 67 amino acid residues with a single disulfide bond. Its N-terminus is blocked by a pyroglutamic acid residue.

Amino acid sequence of the protease inhibitor BWI-4a from buckwheat seeds.

The complete amino acid sequence of protease inhibitor BWI-4a from buckwheat (Fagopyrum esculentum Moench) seeds, consisting of 67 amino acid residues with a single disulfide bond, has been established by Edman degradation in combination with matrix-assisted laser desorption ionization time-of-flight mass spectrometry. Its N terminus is blocked by a pyroglutamic acid residue. Mass spectrometric analysis revealed that inhibitor BWI-4a is present in buckwheat seeds in two isoforms with a single amino acid substitution of Ala40 for Gly40.

Structural analysis of the coat protein of cucumber green mottle mosaic virus.

Using reversed-phase high-performance liquid chromatography, two components of the coat protein of isolate No. 3 of the cucumber green mottle mosaic virus (CGMMV, cucumber strain), Cp1 (minor) and Cp2 (major), were isolated and characterized by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOFMS). In the Cp2 mass spectrum, two polypeptides with Mr of 16,727.

Determination of disulfide bonds in gamma-46 gliadin.

The disulfide bonds in gamma-46 gliadin were identified: Cys173--Cys192, Cys212--Cys291, Cys165--Cys199 (or Cys200), Cys283--Cys200 (or Cys199). The disulfide-containing peptides were obtained by limited hydrolysis of the intact protein with chymotrypsin at an enzyme/substrate ratio of 1:1000 at 20 degrees C for 22 h with subsequent digestion of disulfide-containing fragments with trypsin and chymotrypsin. The locations of disulfide bonds were determined by sequencing disulfide-containing fractions and constituent peptides and comparison of the obtained sequences with the partial amino acid sequence of gamma-46 gliadin determined earlier.

Partial amino acid sequence of gamma-46 gliadin.

We have determined the partial amino acid sequence (207 amino acids) of gamma-46 gliadin isolated from wheat cultivar Hardi. The molecular mass of the protein (Mr) estimated by electrospray mass spectrometry is 35191.3.

Disulphide structure of a sunflower seed albumin: conserved and variant disulphide bonds in the cereal prolamin superfamily.

Disulphide mapping of a methionine-rich 2S albumin from sunflower seeds showed four intra-chain disulphide bonds which are homologous with those in a related heterodimeric albumin from lupin seeds (conglutin delta). Similar conserved disulphide bonds are also present in alpha-gliadin and gamma-gliadin storage proteins of wheat, but a lower level of conservation is present in a further related group of proteins, the cereal inhibitors of alpha-amylase and trypsin. These differences may relate to the different functions of the proteins.

Characterization of the human small-ribosomal-subunit proteins by N-terminal and internal sequencing, and mass spectrometry.

Reverse-phase HPLC was used to fractionate 40S ribosomal proteins from human placenta. Application of a C4 reverse-phase column allowed us to obtain 27 well-resolved peaks. The protein composition of each chromatographic fraction was established by two-dimensional polyacrylamide gel electrophoresis and N-terminal sequencing.

Complete amino acid sequence of the protease inhibitor from buckwheat seeds.

The complete amino acid sequence of protease inhibitor BWI-1 from buckwheat (Fagopyrum esculentum Moench) seeds has been established by automatic Edman degradation and mass spectrometry. The molecule of the inhibitor consists of 69 amino acid residues, with a molecular mass calculated as 7743.8 Da.

The complete amino acid sequence and disulphide bond arrangement of oat alcohol-soluble avenin-3.

We have elucidated the complete amino acid sequence of one of the avenin components, avenin-3, isolated from oat (Avena sativa L.), variety Narymsky 943. The sequence of the protein was determined by sequencing of CNBr and trypsin-generated peptides in combination with mass spectrometry.

Identification of an allelic variant of isoform MLC1-V/sB (human myosin light chain).

A study of 250 specimens of human myocardium by two-dimensional gel electrophoresis revealed an allelic variant of isoform MLC1-V/sB, which was identified by immunoblotting with monoclonal antibody against MLC1-V/sB and peptide mapping after in situ tryptic digestion of electroblotted proteins. The substitution Asn-144 for His-144 was found in this new allelic variant of MLC1-V/sB.