ダプトマイシン
ダプトマイシンはグラム陽性菌の細胞膜にカルシウムイオン濃度依存的に結合し、細胞膜中で多量体(オリゴマー)を形成し、膜電位の脱分極を引き起こし、カリウムイオンを流出させる。その結果、蛋白質、DNA及びRNAの合成を阻害し、細胞融解を引き起こすことなく細菌を死滅させる。
An adenylation domain selects the amino acid monomer to be incorporated and activates the carboxylate with ATP to make the aminoacyl-AMP. Next, the A domain installs an aminoacyl group on the thiolate of the adjacent T domain. The condensation (C) domain catalyzes the peptide bond forming reaction, which elicits chain elongation. It joins an upstream peptidyl-S-T to the downstream aminoacyl-S-T (Figure 7). Chain elongation by one aminoacyl residue and chain translocation to the next T domain occurs in concert. The order of these domains is C-A-T. In some instances, an epimerization domain is necessary in those modules where L-amino acid monomers are to be incorporated and epimerized to D-amino acids. The domain organization in such modules is C-A-T-E.