Department of Chemical Engineering, Princeton University, A207 Engineering Quadrangle, Princeton, New Jersey 08544, USA.
J Am Chem Soc. 2010 Mar 3;132(8):2514-5. doi: 10.1021/ja910191u.
The antimicrobial peptide microcin J25 (MccJ25) is matured by two enzymes, McjB and McjC, from a 58 amino acid (aa) preprotein, McjA, into its final 21 aa lasso topology. Herein we have investigated the role of the leader peptide of McjA and found that only the eight C-terminal amino acids of this leader peptide are required for maturation of MccJ25. There is a high content of lysine residues in the McjA leader peptide, but herein we also demonstrate that these charged amino acids do not play a major role in the maturation of MccJ25. Alanine scanning mutagenesis studies revealed that the Thr-35 residue in the leader peptide is critical for correct processing of McjA into mature MccJ25. In the absence of detailed structural and biochemical data about McjB and McjC, these studies allow us to propose a putative role for the leader peptide as a simple motif for docking of the McjA preprotein in the maturation enzymes.
抗菌肽微菌素 J25（MccJ25）由 McjB 和 McjC 两种酶从 58 个氨基酸（aa）前体蛋白 McjA 成熟为最终的 21 个 aa 套索拓扑结构。在此，我们研究了 McjA 前导肽的作用，发现只有这个前导肽的八个 C 末端氨基酸是成熟 MccJ25 所必需的。McjA 前导肽中含有高含量的赖氨酸残基，但在此我们也证明这些带电荷的氨基酸在 MccJ25 的成熟过程中不起主要作用。丙氨酸扫描诱变研究表明，前导肽中的 Thr-35 残基对于 McjA 正确加工成成熟的 MccJ25 至关重要。在缺乏关于 McjB 和 McjC 的详细结构和生化数据的情况下，这些研究使我们能够提出一个假设，即前导肽作为 McjA 前体蛋白在成熟酶中的对接的简单模体。
