Mapping and identification of the region and secondary structure required for the maturation of the nukacin ISK-1 prepeptide.

The prepeptide NukA of the lantibiotic nukacin ISK-1 consists of an N-terminal leader peptide followed by a propeptide moiety that undergoes post-translational modifications, that is, formation of unusual amino acids by NukM, cleavage of the leader peptide and transport by NukT to yield a mature peptide. To identify the region and conformation required for the maturation of prepeptide, we expressed a series of NukA mutants, mutants with the N-terminus-truncated leader peptide and site-directed mutants with conserved residues in the leader peptide of type A(II) lantibiotics, which were evaluated on the basis of the production of nukacin ISK-1. In addition, the secondary structure data of NukA mutants or fragments were obtained by circular dichroism spectra.

Modulation of proliferation and differentiation of C2C12 skeletal muscle cells by fatty acids.

Aims: This study was performed to elucidate whether mitogen-activated protein kinases (MAPKs) are involved in the modulation of the proliferation and differentiation of skeletal muscle cells by fatty acids.

Main Methods: C2C12 myoblasts were cultured in differentiation medium containing 2% horse serum for 3 days, and treated with each fatty acid. Phosphorylation levels of MAPKs were examined by immunoblot analysis.