Two class II D-tagatose-bisphosphate aldolases from enteric bacteria
Two class II D-tagatose-bisphosphate aldolases from enteric bacteria
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DOI：
10.1007/s00203-002-0406-6
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发表时间：
2002-05-01
影响因子：
2.8
通讯作者：
Lengeler, JW
中科院分区：
文献类型：
--
作者：
Brinkkötter, A;Shakeri-Garakani, A;Lengeler, JW
发现大肠杆菌肠道沙门氏菌、肺炎克雷伯氏菌和产酸克雷伯氏菌含有两种D-塔格糖1，6-二磷酸（TagBP）特异性醛缩酶，其参与半乳糖醇（基因gatY gatZ）和N-乙酰基-半乳糖胺和D-半乳糖胺（基因kbaY kbaZ，也称为agaY agaZ）的催化。这两种醛缩酶的氨基酸序列同源性大于或等于53.8%，在体内可以相互替代。单独的催化亚基GatY或KbaY足以显示醛缩酶活性。虽然基本上短于其他醛缩酶（285个氨基酸，而不是358和349个氨基酸），这些亚基含有大部分或所有的残基，已被确定为在底物/产物识别和催化H类醛缩酶的必要。与此相反，这两种醛缩酶都需要亚基GatZ或KbaZ（420个氨基酸）的完全活性和良好的体内和体外稳定性。单独的Z亚基不显示任何醛缩酶活性。在几种革兰氏阴性和革兰氏阳性细菌中发现了这些新的TagBP醛缩酶的近亲，例如，天蓝色链霉菌
Escherichia coli Salmonella enterica, Klebsiella pneumoniae and Klebsiella oxytoca were found to contain two D-tagatose 1,6-bisphosphate (TagBP)-specific aldolases involved in catabolism of galactitol (genes gatY gatZ) and of N-acetyl-galactosamine and D-galactosamine (genes kbaY kbaZ, also called agaY agaZ). The two aldolases were closely related ( greater than or equal to53.8% identical amino acids) and could substitute for each other in vivo. The catalytic subunits GatY or KbaY alone were sufficient to show aldolase activity. Although substantially shorter than other aldolases (285 amino acids, instead of 358 and 349 amino acids), these subunits contained most or all of the residues that have been identified as essential in substrate/product recognition and catalysis for class H aldolases. In contrast to these, both aldolases required subunits GatZ or KbaZ (420 amino acids) for full activity and for good in vivo and in vitro stability. The Z subunits alone did not show any aldolase activity. Close relatives of these new TagBP aldolases were found in several gram-negative and gram-positive bacteria, e.g., Streptomyces coelicolor.