Asp141 and the hydrogen-bond chain Asp141–Asn109–Asp33 are respectively essential for GT80 sialyltransferase activity and structural stability
Asp141 and the hydrogen-bond chain Asp141–Asn109–Asp33 are respectively essential for GT80 sialyltransferase activity and structural stability
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DOI：
10.1134/s0006297915080131
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发表时间：
2015-08
期刊：
影响因子：
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通讯作者：
Xiaoyan Chen;Yuanming Wang;Zhenping Ma;Nan Li;Weiqing Han;Qi Zhang;Yumei Cai;Jiansong Cheng
中科院分区：
文献类型：
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作者：
Xiaoyan Chen;Yuanming Wang;Zhenping Ma;Nan Li;Weiqing Han;Qi Zhang;Yumei Cai;Jiansong Cheng
唾液酸转移酶是自然界中参与生物学和病理学上重要的含唾液酸分子的生物合成的关键酶。在这项研究中，一个假定的唾液酸转移酶（Pm0160）的活动，窝藏在保守的DDG基序，这已被确定在GT 52和GT 80家庭的固有突变D141 Y，恢复回复突变。更有趣的是，一个氢键链被发现形成之间的三个保守的残基（Asp141，Asn109，和Asp33）的GT 80唾液酸转移酶基于最近确定的晶体结构。我们的诱变实验表明，连接通用碱基Asp141与Nβ4、Nβ1和Nα1的氢键链在维持蛋白质结构稳定性方面起着至关重要的作用，而不是使通用碱基Asp141保持在用于唾液酸转移的生产性方向。
Sialyltransferases are key enzymes involved in the biosynthesis of biologically and pathologically important sialic acid-containing molecules in nature. In this study, the activity of a putative sialyltransferase (Pm0160) harboring an inherent mutation D141Y in the conserved DDG motif, which has been identified in GT52 and GT80 families, was restored by reverse mutation. More interestingly, a hydrogen-bond chain was found to form between three conserved residues (Asp141, Asn109, and Asp33) of GT80 sialyltransferases based on recently determined crystal structures. Our mutagenesis experiments demonstrated that the hydrogen-bond chain connecting the general base Asp141 with Nβ4, Nβ1, and Nα1 plays an essential role in maintaining protein structural stability other than keeping the general base Asp141 in a productive orientation for sialic acid transfer.