School of Chemical and Biological Engineering, Seoul National University, Seoul, Korea.
Appl Microbiol Biotechnol. 2010 May;86(5):1485-92. doi: 10.1007/s00253-009-2368-y. Epub 2009 Dec 19.
Phosphomannomutase (ManB), whose main function is the conversion of mannose-6-phosphate to mannose-1-phosphate, is involved in biosynthesis of GDP-mannose for numerous processes such as synthesis of structural carbohydrates, production of alginates and ascorbic acid, and post-translational modification of proteins in prokaryotes and eukaryotes. ManB isolated from Streptomyces coelicolor was shown to have both phosphomannomutase and phosphoglucomutase activities. Deletion of manB in S. coelicolor caused a dramatic increase in actinorhodin (ACT) production in the low-glucose Difco nutrient (DN) medium, whereas the wild-type strain did not produce ACT on this medium. Experiments involving complementation of the manB deletion showed that increased ACT production in DN media was due to blockage of phosphomannomutase activity rather than phosphoglucomutase activity. This result therefore provides useful information for the design of strategies that enhance antibiotic production through the control of carbon flux.
磷酸甘露糖变位酶（ManB）的主要功能是将 6-磷酸甘露糖转化为 1-磷酸甘露糖，它参与了 GDP-甘露糖的生物合成，用于许多过程，如结构碳水化合物的合成、藻酸盐和抗坏血酸的生产，以及原核生物和真核生物中蛋白质的翻译后修饰。从链霉菌中分离出的 ManB 同时具有磷酸甘露糖变位酶和磷酸葡萄糖变位酶活性。链霉菌中 manB 的缺失导致在低葡萄糖 Difco 营养（DN）培养基中放线紫红素（ACT）的产量显著增加，而野生型菌株在该培养基上不产生 ACT。涉及 manB 缺失的互补实验表明，DN 培养基中 ACT 产量的增加是由于磷酸甘露糖变位酶活性的阻断，而不是磷酸葡萄糖变位酶活性的阻断。因此，该结果为通过控制碳通量来设计增强抗生素生产的策略提供了有用的信息。
