Department of Medicinal Chemistry and Pharmacognosy, College of Pharmacy, University of Illinois at Chicago, Chicago, Illinois 60612, United States.
J Nat Prod. 2010 Nov 29;73(11):1927-32. doi: 10.1021/np100600z. Epub 2010 Nov 8.
Two cyclic peptides, scytonemides A (1) and B (2), were isolated from the cultured fresh water cyanobacterium Scytonema hofmannii (UTEX 1834) by bioassay-guided fractionation using a proteasome inhibition assay. The planar structures of the compounds were determined by a combination of MS and 1D and 2D NMR spectroscopy. The advanced Marfey's method was used to determine the absolute configuration of both peptides. Scytonemide A possesses an unusual imino linkage, while scytonemide B is a depsipeptide containing 3-hydroxyoctanoic acid in the macrocycle. Both isolates were evaluated for their inhibition of the 20S proteasome, and scytonemide A displayed an IC(50) value of 96 nM, while scytonemide B was inactive at 50 μM.
从培养的淡水蓝藻 Scytonema hofmannii（UTEX 1834）中，通过基于蛋白酶体抑制测定的生物测定指导的分步分离，分离出两种环肽，即 scytonemide A（1）和 B（2）。通过 MS 和 1D 和 2D NMR 光谱的组合确定了化合物的平面结构。高级 Marfey 法用于确定两种肽的绝对构型。Scytonemide A 具有不寻常的亚氨基键，而 scytonemide B 是一种含有 3-羟基辛酸的环肽。对两种分离物进行了对 20S 蛋白酶体抑制的评估，scytonemide A 的 IC50 值为 96 nM，而 scytonemide B 在 50 μM 时无活性。
