Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, California 92093-0358, United States.
J Nat Prod. 2012 Mar 23;75(3):425-31. doi: 10.1021/np200861n. Epub 2012 Feb 23.
The absolute stereostructures of the components of symplocin A (3), a new N,N-dimethyl-terminated peptide from the Bahamian cyanobacterium Symploca sp., were assigned from spectroscopic analysis, including MS, 2D NMR, and Marfey's analysis. The complete absolute configuration of symplocin A, including the unexpected D-configurations of the terminal N,N-dimethylisoleucine and valic acid residues, was assigned by chiral-phase HPLC of the corresponding 2-naphthacyl esters, a highly sensitive, complementary strategy for assignment of N-blocked peptide residues where Marfey's method is ineffectual or other methods fall short. Symplocin A exhibited potent activity as an inhibitor of cathepsin E (IC(50) 300 pM).
从包括 MS、2D NMR 和 Marfey 分析在内的光谱分析中，确定了来自巴哈马蓝藻 Symploca sp. 的新型 N,N-二甲基端缩肽 symplocin A（3）的各个组分的绝对立体结构。通过相应的 2-萘酰基酯的手性相 HPLC，确定了 symplocin A 的完整绝对构型，包括末端 N,N-二甲基异亮氨酸和缬氨酸残基的意外 D 构型，这是一种非常灵敏、互补的策略，可用于分配 N-封闭肽残基，其中 Marfey 方法无效或其他方法不足。Symplocin A 表现出作为组织蛋白酶 E（IC50 300 pM）抑制剂的强大活性。
