Enterococcus faecalis utilizes maltose by connecting two incompatible metabolic routes via a novel maltose 6'-phosphate phosphatase (MapP).
Enterococcus faecalis utilizes maltose by connecting two incompatible metabolic routes via a novel maltose 6'-phosphate phosphatase (MapP).
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DOI：
10.1111/mmi.12183
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发表时间：
2013-04
影响因子：
3.6
通讯作者：
Deutscher J
中科院分区：
文献类型：
--
作者：
Mokhtari A;Blancato VS;Repizo GD;Henry C;Pikis A;Bourand A;de Fátima Álvarez M;Immel S;Mechakra-Maza A;Hartke A;Thompson J;Magni C;Deutscher J
与枯草芽孢杆菌类似，粪肠球菌通过磷酸烯醇丙酮酸（PEP）：麦芽糖磷酸转移酶系统（PTS）转运麦芽糖并使其磷酸化。麦芽糖特异性PTS渗透酶由麦芽糖基因编码。然而，粪肠杆菌缺乏编码6-磷酸-α-葡萄糖苷酶的malA基因，该基因在枯草芽孢杆菌中可将麦芽糖-6′-P水解为葡萄糖和葡萄糖-6-P。相反，编码麦芽糖磷酸化酶（MalP）、磷酸葡萄糖葡萄糖化酶和突变酶的操纵子从malT上游开始。MalP建议将麦芽糖-6- p分解为葡萄糖-1- p和葡萄糖-6- p。然而，纯化的MalP能磷酸化麦芽糖，但不能磷酸化麦芽糖-6′-P。我们发现malT下游的基因编码一种新型酶（MapP），该酶可使PTS形成的麦芽糖-6′-P去磷酸化。产生的细胞内麦芽糖被MalP裂解成葡萄糖和葡萄糖-1- p。麦芽糖的缓慢摄取可能是通过麦芽糖糊精ABC转运体导致的，这使得mapP生长不良，而malP突变体则不然。积累麦芽糖-6′-P的枯草芽孢杆菌突变体MapP的合成恢复了麦芽糖的生长。MapP催化细胞内麦芽糖-6′-P的去磷酸化，产生的麦芽糖被枯草芽孢杆菌麦芽糖磷酸化酶转化为葡萄糖和葡萄糖-1-P。因此，MapP将pts介导的麦芽糖摄取与麦芽糖磷酸化酶催化的代谢联系起来。用多种磷酸化底物进行的去磷酸化实验表明，MapP可以更好地去磷酸化含有O-α-糖基连接的双糖。
Similar to Bacillus subtilis, Enterococcus faecalis transports and phosphorylates maltose via a phosphoenolpyruvate (PEP):maltose phosphotransferase system (PTS). The maltose-specific PTS permease is encoded by the malT gene. However, E. faecalis lacks a malA gene encoding a 6-phospho-α-glucosidase which in B. subtilis hydrolyses maltose-6’-P into glucose and glucose-6-P. Instead, an operon encoding a maltose phosphorylase (MalP), a phosphoglucomutase and a mutarotase starts upstream from malT. MalP was suggested to split maltose-6-P into glucose-1-P and glucose-6-P. However, purified MalP phosphorolyses maltose but not maltose-6’-P. We discovered that the gene downstream from malT encodes a novel enzyme (MapP) that dephosphorylates maltose-6’-P formed by the PTS. The resulting intracellular maltose is cleaved by MalP into glucose and glucose-1-P. Slow uptake of maltose probably via a maltodextrin ABC transporter allows poor growth for the mapP but not the malP mutant. Synthesis of MapP in a B. subtilis mutant accumulating maltose-6’-P restored growth on maltose. MapP catalyzes the dephosphorylation of intracellular maltose-6’-P, and the resulting maltose is converted by the B. subtilis maltose phosphorylase into glucose and glucose-1-P. MapP therefore connects PTS-mediated maltose uptake to maltose phosphorylase-catalyzed metabolism. Dephosphorylation assays with a wide variety of phospho-substrates revealed that MapP preferably dephosphorylates disaccharides containing an O-α-glycosyl linkage.
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影响因子：
2.1
作者：
FRIESENEGGER, A;FIEDLER, S;WIRTH, R
通讯作者：
WIRTH, R
影响因子：
4.8
作者：
Andersson, U;Levander, F;Rådström, P
通讯作者：
Rådström, P
影响因子：
3.2
作者：
Dippel, R;Boos, W
通讯作者：
Boos, W
影响因子：
9.4
作者：
Nallapareddy, SR;Duh, RW;Murray, BE
通讯作者：
Murray, BE
影响因子：
10.7
作者：
Hall, Barry G.;Pikis, Andreas;Thompson, John
通讯作者：
Thompson, John