Wang Tsung-Shing Andrew, Manning Sara Aviva, Walker Suzanne, Kahne Daniel
Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts 02138, USA.
J Am Chem Soc. 2008 Oct 29;130(43):14068-9. doi: 10.1021/ja806016y. Epub 2008 Oct 4.
Peptidoglycan is an essential component of bacterial cell wall. The glycan strands of peptidoglycan are synthesized by enzymes called peptidoglycan glycosyltransferases (PGTs). Using a high-resolution SDS-PAGE assay, we compared the glycan strand lengths of four different PGTs from three different organisms (Escherichia coli, Enterococcus faecalis, and Staphylococcus aureus). We report that each enzyme makes a polymer having an intrinsic characteristic length that is independent of the enzyme:substrate ratio. The glycan strand lengths vary considerably, depending on the enzyme. These results indicate that each enzyme must have some mechanism, as yet unknown, for controlling product length. The observation that different PGTs produce different length glycan chains may have implications for their cellular roles and for the three-dimensional structure of bacterial peptidoglycan.
肽聚糖是细菌细胞壁的重要组成部分。肽聚糖的聚糖链由称为肽聚糖糖基转移酶（PGT）的酶合成。我们使用高分辨率SDS-PAGE测定法，比较了来自三种不同生物体（大肠杆菌、粪肠球菌和金黄色葡萄球菌）的四种不同PGT的聚糖链长度。我们报告称，每种酶都能合成一种具有内在特征长度的聚合物，该长度与酶与底物的比例无关。聚糖链长度根据酶的不同而有很大差异。这些结果表明，每种酶必定具有某种尚未知晓的控制产物长度的机制。不同PGT产生不同长度聚糖链这一观察结果，可能对它们在细胞中的作用以及细菌肽聚糖的三维结构具有重要意义。
