Maillard Noélie, Darbre Tamis, Reymond Jean-Louis
Department of Chemistry and Biochemistry, University of Berne, Freiestrasse 3, Berne, Switzerland.
J Comb Chem. 2009 Jul-Aug;11(4):667-75. doi: 10.1021/cc9000289.
A combinatorial library of up to 65'536 peptide dendrimers (AcX(8)X(7))(8)(DapX(6)X(5))(4)(DapX(4)X(3))(2)DapX(2)X(1) (Dap = (S)-2,3-diaminopropionic acid branching point, X(8-1) = groups of four proteinogenic l-amino acids) was prepared on a photocleavable tentagel resin. The library was assayed for catalytic hydrolysis of the fluorogenic substrate 1-butyryloxy-pyrene-2,7,8-trisulfonate 1 and analogs by a simple procedure involving (a) photocleavage from the support in the absence of solvent, (b) spreading of the solid support beads on the surface of a silicagel plate impregnated with an aqueous buffered substrate solution, and (c) identification of hits as beads surrounded by a fluorescent halo indicative of catalysis and sequence determination in hits and nonhits by amino acid analysis of the beads. The experiment provides direct access to structure-activity relationships in the library and delivers active esterase dendrimers. Anionic glutamate residues in the outer dendrimer branches were found to inhibit catalysis by histidine residues at the dendrimer core. The "off-bead" in silica assay is simple to implement and transferable to other library and reaction types.
在光可裂解的帐篷凝胶树脂上制备了一个包含多达65536种肽树枝状聚合物（AcX(8)X(7))(8)(DapX(6)X(5))(4)(DapX(4)X(3))(2)DapX(2)X(1)（Dap = (S)-2,3-二氨基丙酸分支点，X(8 - 1) = 四组蛋白质ogenic l-氨基酸）的组合文库。通过一个简单的程序对该文库进行了荧光底物1-丁酰氧基芘-2,7,8-三磺酸盐1及其类似物的催化水解测定，该程序包括：(a) 在无溶剂条件下从载体上进行光裂解；(b) 将固体载体珠粒铺展在浸渍有缓冲底物水溶液的硅胶板表面；(c) 将产生荧光晕圈（表明有催化作用）的珠粒鉴定为活性物质，并通过对珠粒的氨基酸分析确定活性物质和非活性物质的序列。该实验直接揭示了文库中的构效关系，并得到了具有活性的酯酶树枝状聚合物。发现树枝状聚合物外层分支中的阴离子谷氨酸残基会抑制树枝状聚合物核心处组氨酸残基的催化作用。硅胶板上的“离珠”测定法易于实施，且可应用于其他文库和反应类型。
