N-acetyl-heparosan lyase of Escherichia coli K5: Gene cloning and expression
N-acetyl-heparosan lyase of Escherichia coli K5: Gene cloning and expression
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DOI：
10.1128/jb.178.24.7260-7264.1996
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发表时间：
1996-12-01
影响因子：
3.2
通讯作者：
Salome, M
中科院分区：
文献类型：
--
作者：
Legoux, R;Lelong, P;Salome, M
大肠杆菌K5的荚膜多糖的结构与肝素的非磺化前体n -乙酰肝素聚糖相同，这使得这种大肠杆菌抗原成为化学合成低分子量肝素类似物的一个有吸引力的起点。这种多糖被合成为一种高分子量分子，可以被一种具有内切-消除酶活性的酶解聚。通过在大肠杆菌K-12中表达，从大肠杆菌K5中克隆出了消除酶编码基因elmA。K-12基因组缺乏elmA序列。elmA基因产物长820个氨基酸。活性重组消除酶是由K-12细胞以细胞结合和分泌形式产生的。缺失分析表明，C端和N端分别是活性和分泌所必需的。
The structure of the capsular polysaccharide of Escherichia coli K5 is identical to that of N-acetyl-heparosan, a nonsulfated precursor of heparin, which makes this E. coli antigen an attractive starting point for the chemical synthesis of analogs of low-molecular-weight heparin. This polysaccharide is synthesized as a high-molecular-weight molecule that can be depolymerized by an enzyme displaying endo-beta-eliminase activity. The eliminase-encoding gene, designated elmA, has been cloned from E. coli K5 by expression in E. coli K-12. The K-12 genome is devoid of the elmA sequence. The elmA gene product is 820 amino acids long. Active recombinant eliminase is produced by K-12 cells in both cell-bound and secreted forms. Deletion analyses have shown that the C terminus and the N terminus are required for activity and secretion, respectively.