Centre de Recherches du Cyclotron, B30, Université de Liège, Allée du 6 août 8, Sart Tilman, B 4000 Liège, Belgium.
Bioorg Med Chem. 2010 Nov 1;18(21):7422-31. doi: 10.1016/j.bmc.2010.09.010. Epub 2010 Sep 8.
Various peptidoglycan fragments were synthesized from two anhydro-muramic acid derivatives protected with a Bn or a PMB group at the 4th position, in homogenate phase or on a solid support. In order to facilitate HPLC detection, a chromophoric group was attached to the peptide chain. The periplasmic amidase sAmiD of Escherichia coli was used to cleave the amide bond between the lactyl group of the MurNAc and the α-amino group of L-Ala where the peptide chain was at least a dipeptide (L-Ala-γ-D-Glu) amidated by benzylamine on the γ-carboxyl group of D-Glu. In the presence of a tripeptide chain (L-Ala-γ-D-Glu-L-Lys) or a tetrapeptide chain (L-Ala-γ-D-Glu-m-A(2)pm-D-Ala) higher hydrolysis rates were observed. We have also demonstrated that the presence of TNB on the ε-amino group of L-Lys only has a small influence on the hydrolysis capacity of sAmiD.
从保护 4 位的 Bn 或 PMB 基团的两种脱水 muramic 酸衍生物合成了各种肽聚糖片段，在均相相或在固体载体上进行。为了便于 HPLC 检测，在肽链上连接了生色基团。使用大肠杆菌的周质酰胺酶 sAmiD 切割 MurNAc 的乳酰基和 L-Ala 的α-氨基之间的酰胺键，其中肽链至少是二肽（L-Ala-γ-D-Glu），通过苄胺在 D-Glu 的γ-羧基上酰胺化。当存在三肽链（L-Ala-γ-D-Glu-L-Lys）或四肽链（L-Ala-γ-D-Glu-m-A（2）pm-D-Ala）时，观察到更高的水解速率。我们还证明了 L-Lys 的ε-氨基上存在 TNB 对 sAmiD 的水解能力只有很小的影响。
