Johnston L S, Neuhaus F C
Biochemistry. 1975 Jun 17;14(12):2754-60. doi: 10.1021/bi00683a031.
Phospho-N-acetylmuramyl-pentapeptide translocase (UDP-MurNAc-Ala-DGlu-Lys-DAla-DAla:undecaprenyl phosphate, phospho-MurNAc-pentapeptide transferase) catalyzes the initial membrane reaction in the biosynthesis of peptidoglycan. The spin-labeled nucleotide, UDP-MurNAc-Ala-DGlu-Lys (Nepsilon-2,2,5,5-tetramethyl-N-oxyl-pyrroline-3-carbonyl)-DAla-DAla, was used as a substrate by this enzyme for the synthesis of membrane-associated undecaprenyl-diphosphate-MurNAc-Ala-DGlu-Lys(Nepsilon-Tempyo)-DAla-DAla. The spin-labeled substrate and product complex with the antibiotics vancomycin and ristocetin. The association constants for the spin-labeled nucleotide are 6.2 times 10(5) and 6.2 times 10(4) M-1 for vancomycin and ristocetin, respectively. The association constants for the spin-labeled lipid intermediate are 3.0 times 10(4) and 2.1 times 10(4) M-1 for vancomycin and ristocetin, respectively. These results indicate that the acyl-DAla termini of membranes-associated spin-labeled undecaprenyl-diphosphate-MurNAc-pentapeptide are accessible to vancomycin and ristocetin and that the association constants are smaller than those determined for the corresponding antibiotic spin-labeled UDP-MurNAc-pentapeptide complexes.
磷酸 - N - 乙酰胞壁酰 - 五肽转位酶（UDP - MurNAc - Ala - D - Glu - Lys - D - Ala - D - Ala：十一异戊烯磷酸，磷酸 - MurNAc - 五肽转移酶）催化肽聚糖生物合成中的初始膜反应。自旋标记的核苷酸UDP - MurNAc - Ala - D - Glu - Lys（Nε - 2,2,5,5 - 四甲基 - N - 氧代 - 吡咯啉 - 3 - 羰基） - D - Ala - D - Ala被该酶用作底物，用于合成膜相关的十一异戊烯二磷酸 - MurNAc - Ala - D - Glu - Lys（Nε - Tempyo） - D - Ala - D - Ala。自旋标记的底物和产物与抗生素万古霉素和瑞斯托霉素形成复合物。自旋标记核苷酸与万古霉素和瑞斯托霉素的缔合常数分别为6.2×10⁵和6.2×10⁴ M⁻¹。自旋标记脂质中间体与万古霉素和瑞斯托霉素的缔合常数分别为3.0×10⁴和2.1×10⁴ M⁻¹。这些结果表明，膜相关的自旋标记十一异戊烯二磷酸 - MurNAc - 五肽的酰基 - D - Ala末端可被万古霉素和瑞斯托霉素接近，并且缔合常数小于相应抗生素自旋标记UDP - MurNAc - 五肽复合物的缔合常数。
