High-resolution crystal structure of human asparagine synthetase enables analysis of inhibitor binding and selectivity
High-resolution crystal structure of human asparagine synthetase enables analysis of inhibitor binding and selectivity
复制标题
DOI：
10.1038/s42003-019-0587-z
复制
发表时间：
2019-09-17
影响因子：
5.9
通讯作者：
Richards, Nigel G. J.
中科院分区：
文献类型：
--
作者：
Zhu, Wen;Radadiya, Ashish;Richards, Nigel G. J.
人天冬酰胺合成酶（ASNS）的表达促进结肠直肠癌和乳腺癌的转移进展和肿瘤细胞侵袭，可能是通过改变L-天冬酰胺的细胞水平。因此，人ASNS正在成为癌症治疗的真正药物靶标。在这里，我们表明，一种缓慢起效，紧密结合的抑制剂，它表现出纳摩尔亲和力的人ASNS在体外，表现出优异的选择性，在HCT-116细胞裂解物中的浓度为10 μ M，几乎没有脱靶结合。人类ASNS的高分辨率（1.85埃）晶体结构使我们能够确定在抑制剂结合中起关键作用的合成酶结构域中的一簇带负电荷的侧链。将这种结构与进化上相关的AMP形成酶的结构进行比较，可以深入了解引起所观察到的结合选择性的分子间相互作用。我们的研究结果表明，开发第二代人ASNS抑制剂作为发现抗转移药物的先导化合物的可行性。
Expression of human asparagine synthetase (ASNS) promotes metastatic progression and tumor cell invasiveness in colorectal and breast cancer, presumably by altering cellular levels of L-asparagine. Human ASNS is therefore emerging as a bona fide drug target for cancer therapy. Here we show that a slow-onset, tight binding inhibitor, which exhibits nanomolar affinity for human ASNS in vitro, exhibits excellent selectivity at 10 mu M concentration in HCT-116 cell lysates with almost no off-target binding. The high-resolution (1.85 angstrom) crystal structure of human ASNS has enabled us to identify a cluster of negatively charged side chains in the synthetase domain that plays a key role in inhibitor binding. Comparing this structure with those of evolutionarily related AMP-forming enzymes provides insights into intermolecular interactions that give rise to the observed binding selectivity. Our findings demonstrate the feasibility of developing second generation human ASNS inhibitors as lead compounds for the discovery of drugs against metastasis.