Discovery of a Kojibiose Phosphorylase in Escherichia coli K-12.
Discovery of a Kojibiose Phosphorylase in Escherichia coli K-12.
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DOI：
10.1021/acs.biochem.8b00392
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发表时间：
2018-05-15
期刊：
影响因子：
2.9
通讯作者：
Raushel FM
中科院分区：
文献类型：
--
作者：
Mukherjee K;Narindoshvili T;Raushel FM
三个未表征的酶（YcjM，YcjT，和YcjU），表达从一个簇的12个基因（ycjM-W和ompG）的功能未知的大肠杆菌K-12的底物配置文件已被确定。通过综合的生物信息学和稳态动力学分析，确定YcjT的催化功能为曲二糖磷酸化酶。在饱和磷酸盐和曲二糖（α-（1，2）-D-葡萄糖-D-葡萄糖）存在下，该酶催化D-葡萄糖和β-D-葡萄糖-1-磷酸盐的形成（kcat = 1.1 s−1，Km = 1.05 mM，kcat/Km = 1.12 x 103 M−1 s−1）。此外，还表明在β-D-葡萄糖-1-磷酸存在下，YcjT可以催化使用1，5-脱水-D-葡萄糖醇、L-山梨糖、D-山梨糖醇或L-艾杜糖醇作为D-葡萄糖的替代物的其他二糖的形成。曲二糖是革兰氏阳性菌中细胞壁脂磷壁酸的组分，并且作为潜在的低热量甜味剂和益生元而令人感兴趣。YcjU是一种β-磷酸葡萄糖变位酶，催化β-D-葡萄糖-1-磷酸（kcat = 21 s−1，Km = 18 μM，kcat/Km = 1.1 x 106 M−1 s−1）异构化为D-葡萄糖-6-磷酸。还显示YcjU对β-D-阿洛糖-1-磷酸、β-D-甘露糖-1-磷酸和β-D-半乳糖-1-磷酸表现出催化活性。YcjM催化α-（1，2）-D-葡萄糖-D-甘油酸的磷酸解，kcat = 2.1 s−1，Km = 69 μM，kcat/Km = 3.1 x 104 M−1 s−1。
The substrate profiles for three uncharacterized enzymes (YcjM, YcjT, and YcjU) that are expressed from a cluster of twelve genes (ycjM-W and ompG) of unknown function in Escherichia coli K-12 have been determined. Through a comprehensive bioinformatic and steady-state kinetic analysis, the catalytic function of YcjT was determined to be kojibiose phosphorylase. In the presence of saturating phosphate and kojibiose (α-(1,2)-D-glucose-D-glucose) this enzyme catalyzes the formation of D-glucose and β-D-glucose-1-phosphate (kcat = 1.1 s−1, Km = 1.05 mM, and kcat/Km = 1.12 x 103 M−1 s−1). Additionally, it was also shown that in the presence of β-D-glucose-1-phosphate, YcjT can catalyze the formation of other disaccharides using 1,5-anhydro-D-glucitol, L-sorbose, D-sorbitol or L-iditol as a substitute for D-glucose. Kojibiose is a component of cell wall lipoteichoic acids in Gram-positive bacteria and is of interest as a potential low-calorie sweetener and prebiotic. YcjU was determined to be a β-phosphoglucomutase that catalyzes the isomerization of β-D-glucose-1-phosphate (kcat = 21 s−1, Km = 18 μM, and kcat/Km = 1.1 x 106 M−1 s−1) to D-glucose-6-phosphate. YcjU was also shown to exhibit catalytic activity with β-D-allose-1-phosphate, β-D-mannose-1-phosphate, and β-D-galactose-1-phosphate. YcjM catalyzes the phosphorolysis of α-(1,2)-D-glucose-D-glycerate with a kcat = 2.1 s−1, Km = 69 μM, and kcat/Km = 3.1 x 104 M−1 s−1.
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DOI：
10.1016/j.bbapap.2015.04.015
发表时间：
2015-08
影响因子：
3.2
作者：
Gerlt, John A.;Bouvier, Jason T.;Davidson, Daniel B.;Imker, Heidi J.;Sadkhin, Boris;Slater, David R.;Whalen, Katie L.
通讯作者：
Whalen, Katie L.
影响因子：
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作者：
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作者：
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