Pseudo-tri- and -tetra-peptide aminoalkylphosphinic acids of general structure X-Lys-PO2H-Gly-Ala have been synthesised as transition state analogues for D-Ala-D-Ala adding enzyme. The key synthetic step used to assemble the C-terminal dipeptide unit is a modified Arbusov reaction, coupling bromopropionyl-D-alanine methyl ester to a silylated aminoalkylphosphonite. Kinetic assays with the purified E. coli enzyme reveal that the phosphinate analogues act as reversible competitive inhibitors, with Ki values in the range 200–700 µ>M>. Extended analogues mimicking the peptide chain of the UDPMurNAc-L-Ala-γ-D-Glu-m-DAP substrate show increased binding affinity for the enzyme active site. These are the first reported inhibitors for D-Ala-D-Ala adding enzyme.
我们合成了一般结构为 X-Lys-PO2H-Gly-Ala 的伪三肽和四肽
氨基烷基
膦酸,作为 D-Ala-D-Ala 添加酶的过渡态类似物。组装 C 端二肽单元的关键合成步骤是改良的阿勃梭夫反应,将
溴丙酰基-
D-丙氨酸甲酯与
硅烷化的
氨基烷基
膦酸盐偶联。用纯化的大肠杆菌酶进行动力学测定发现,
膦酸盐类似物是可逆的竞争性
抑制剂,Ki 值在 200-700 µ>M> 之间。模仿
UDPMurNAc-L-Ala-γ-D-Glu-m-DAP 底物肽链的扩展类似物显示出与酶活性位点更强的结合亲和力。这是首次报道的 D-Ala-D-Ala 添加酶
抑制剂。