Goodell E W, Higgins C F
J Bacteriol. 1987 Aug;169(8):3861-5. doi: 10.1128/jb.169.8.3861-3865.1987.
During bacterial growth, cell wall peptides are released from the murein and reused for the synthesis of new cell wall material. Mutants defective in peptide transport were unable to reutilize cell wall peptides, demonstrating that these peptides are taken up intact into the cytoplasm prior to reincorporation into murein. Furthermore, cell wall peptide recycling was shown to play an important physiological role; peptide transport mutants which were unable to recycle these peptides showed growth defects under appropriate conditions. Using mutants specifically defective in each of the three peptide transport systems, we showed that the uptake of cell wall peptides was mediated solely by the oligopeptide permease (Opp) and that neither the dipeptide permease (Dpp) nor the tripeptide permease (Tpp) played a significant role in this process. Our data indicate that the periplasmic oligopeptide-binding protein has more than one substrate-binding site, each with different though overlapping specificities.
在细菌生长过程中，细胞壁肽从胞壁质中释放出来，并被重新用于合成新的细胞壁材料。肽转运缺陷型突变体无法再利用细胞壁肽，这表明这些肽在重新掺入胞壁质之前会完整地被吸收到细胞质中。此外，细胞壁肽循环被证明发挥着重要的生理作用；无法循环这些肽的肽转运突变体在适当条件下表现出生长缺陷。利用在三种肽转运系统中各自存在特异性缺陷的突变体，我们发现细胞壁肽的吸收仅由寡肽通透酶（Opp）介导，而二肽通透酶（Dpp）和三肽通透酶（Tpp）在此过程中均未发挥重要作用。我们的数据表明，周质寡肽结合蛋白具有不止一个底物结合位点，每个位点具有不同但重叠的特异性。
