Liposomal encapsulation enhances antiviral efficacy of SPC3 against human immunodeficiency virus type-1 infection in human lymphocytes.

Because encapsulation of antiviral drugs in liposomes resulted generally in improved activity against retroviral replication in vivo, the antiviral effects of free-SPC3 and liposome-associated SPC3 were compared in cultured human lymphocytes infected with HIV-1. SPC3 was entrapped in various liposomal formulations, either different in size (mean diameter of 100 and 250 nm), SPC3 concentration or cholesterol content. Liposome-associated SPC3 were tested for both inhibition of cell-cell fusion and infection with HIV-1 clones.

Disulfide bridge reorganization induced by proline mutations in maurotoxin.

Maurotoxin (MTX) is a 34-residue toxin that has been isolated from the venom of the chactidae scorpion Scorpio maurus palmatus, and characterized. Together with Pi1 and HsTx1, MTX belongs to a family of short-chain four-disulfide-bridged scorpion toxins acting on potassium channels. However, contrary to other members of this family, MTX exhibits an uncommon disulfide bridge organization of the type C1-C5, C2-C6, C3-C4 and C7-C8, versus C1-C5, C2-C6, C3-C7 and C4-C8 for both Pi1 and HsTx1.

KTX3, the kaliotoxin from Buthus occitanus tunetanus scorpion venom: one of an extensive family of peptidyl ligands of potassium channels.

A new ligand of the K+ channels sensitive to KTX was purified from the venom of Buthus occitanus tunetanus, using two steps of high-performance-liquid-chromatography and by following its ability to compete with [125I]-KTX for binding to the KTX receptor on rat brain synaptosomes. Amino-acid analysis, amino acid sequencing and mass spectroscopy defined this new ligand. KTX3, as a 37-amino acid peptide, with three disulfide bridges.

Circular dichroism and molecular modeling of the E. coli TolA periplasmic domains.

Colicins are killer proteins that use envelope proteins from the outer and the inner membranes to reach their cellular target in susceptible cells of Escherichia coli. Each group A colicin uses a combination of Tol proteins to cross the outer membrane of gram-negative bacteria and to exert their killing activity. The TolA protein, necessary for the import of all the group A colicins, is a 421-amino acid residue protein composed of three domains (TolAI, TolAII, and TolAIII).

Maurotoxin, a four disulfide bridges scorpion toxin acting on K+ channels.

Maurotoxin, a toxin from the venom of the Tunisian chactoid scorpion Scorpio maurus, has been purified to homogeneity by gel filtration/reversed-phase HPLC, and characterized. It is a basic and C-terminal amidated 34-residue polypeptide cross-linked by four disulfide bridges. From Edman sequencing results, only six different pairings between the first six half-cystines were retained whereas a disulfide bridge was predicted between the two half-cystines in positions 31 and 34.