PhcrTx2, a New Crab-Paralyzing Peptide Toxin from the Sea Anemone Phymanthus crucifer.

Sea anemones produce proteinaceous toxins for predation and defense, including peptide toxins that act on a large variety of ion channels of pharmacological and biomedical interest. is commonly found in the Caribbean Sea; however, the chemical structure and biological activity of its toxins remain unknown, with the exception of PhcrTx1, an acid-sensing ion channel (ASIC) inhibitor. Therefore, in the present work, we focused on the isolation and characterization of new toxins by chromatographic fractionation, followed by a toxicity screening on crabs, an evaluation of ion channels, and sequence analysis.

A Conus regularis conotoxin with a novel eight-cysteine framework inhibits CaV2.2 channels and displays an anti-nociceptive activity.

A novel peptide, RsXXIVA, was isolated from the venom duct of Conus regularis, a worm-hunting species collected in the Sea of Cortez, México. Its primary structure was determined by mass spectrometry and confirmed by automated Edman degradation. This conotoxin contains 40 amino acids and exhibits a novel arrangement of eight cysteine residues (C-C-C-C-CC-CC).

Arrhythmogenic effect of a crude extract from sea anemone Condylactis gigantea: possible involvement of rErg1 channels.

Sea anemones possess a number of peptide toxins that target ion channels which provide powerful tools to study the molecular basis of diverse signaling pathways. It is also acknowledged that currents through Erg1 K(+) channels in cardiac myocytes are important for electrical stability of the heart and alterations in its activity has been linked to the onset of a potentially life-threatening heart condition named long QT syndrome type 2. Here, we report that a crude extract from sea anemone Condylactis gigantea significantly increases the QT interval and has arrhythmogenic effects in the rat heart.

Biochemical characterization of recombinant L-asparaginase (AnsA) from Rhizobium etli, a member of an increasing rhizobial-type family of L-asparaginases.

We report the expression, purification, and characterization of L-asparaginase (AnsA) from Rhizobium etli. The enzyme was purified to homogeneity in a single-step procedure involving affinity chromatography, and the kinetic parameters K(m), V(max), and k(cat) for L-asparagine were determined. The enzymatic activity in the presence of a number of substrates and metal ions was investigated.

Effects of salts on aerobic metabolism of Debaryomyces hansenii.

Debaryomyces hansenii was grown in YPD medium without or with 1.0 M NaCl or KCl. Respiration was higher with salt, but decreased if it was present during incubation.

Effect of alkaline deamidation on the structure, surface hydrophobicity, and emulsifying properties of the Z19 alpha-zein.

Different deamidation conditions for the Z19 alpha-zein were studied in order to find the best conditions for the development of the emulsifying properties. Alkaline deamidation was chosen, and the effects on the peptide bond cleavage, secondary structure, emulsifying properties, and surface hydrophobicity were studied. The Z19 alpha-zein was deamidated by using 0.

Effect of temperature and pH on the secondary structure and processes of oligomerization of 19 kDa alpha-zein.

Highly hydrophobic protein Z19 zein shows a tendency towards oligomerization. The role of temperature and pH on the oligomerization process was studied monitoring the secondary structure content and the appearance of aggregates by Circular Dichroism Spectroscopy (CD) and Dinamic Light Scattering (DLS). Z19 zein suffers irreversible thermal denaturalization, as demonstrated by far-UV CD measurements.

Characterization of a 19 kDa alpha-zein of high purity.

A highly pure alpha-zein was extracted from corn flour using ethanol (95%). Subsequently, ion-exchange chromatography was performed, using SP-Sepharose that yielded a highly homogeneous protein. This protein migrated as a single band in 20% SDS-PAGE and in pH gradient gels, showing an isoelectric point of 6.

Purification and characterization of liver lectins from a lizard, Sceloporus spinosus.

This study discusses the purification of soluble beta-galactose lectins obtained from the lizard liver of Sceloporus spinosus. The first lectin named lizard hepatic lectin-1 (LHL-1) presented a molecular weight of 31,750, with an isoelectric point of 4.25.