Comparative study of the binding pockets of mammalian proprotein convertases and its implications for the design of specific small molecule inhibitors.
Comparative study of the binding pockets of mammalian proprotein convertases and its implications for the design of specific small molecule inhibitors.
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DOI：
10.7150/ijbs.6.89
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发表时间：
2010-02-03
影响因子：
9.2
通讯作者：
Jianhua W
中科院分区：
文献类型：
--
作者：
Tian S;Jianhua W
前蛋白转化酶是在分泌途径中蛋白水解切割蛋白质前体以产生功能蛋白的酶。已经鉴定了七种哺乳动物枯草杆菌蛋白酶/Kex 2 p样前蛋白转化酶：弗林蛋白酶、PC 1、PC 2、PC 4、PACE 4、PC 5和PC 7。所有七种前蛋白转化酶的结合口袋在进化上是保守的并且高度相似。在七种前蛋白转化酶中，弗林蛋白酶切割位点基序最近被表征为20个残基基的基序，其包括弗林蛋白酶结合口袋内的一个核心区域P6-P2 ′。这项研究通过检查弗林蛋白酶底物核心区域P6-P2 ′周围的弗林蛋白酶结合口袋的3D结构环境扩展了这一信息。其他六种哺乳动物前蛋白转化酶的结合口袋中的突变的物理性质进行了比较。结果表明：1）Glu 230和Glu 257两个位置的突变改变了结合口袋的负电荷的总密度，并控制了哺乳动物前蛋白转化酶的底物特异性; 2）两种前蛋白转化酶（PC 1和PC 2）可能对底物位置P5或P6的带正电荷残基具有降低的敏感性，而三种前蛋白转化酶的底物特异性（弗林蛋白酶、PACE 4和PC 5）彼此相似。这一发现导致了小分子抑制剂的短肽模式的新设计：[K/R]-X-V-X-K-R。与广泛使用的抑制所有七种前蛋白转化酶的小分子dec-RVKR-cmk相比，短肽模式的微调衍生物[K/R]-X-V-X-K-R可能具有比其余两种（PC 1和PC 2）更有效地抑制五种前蛋白转化酶（弗林蛋白酶、PC 4、PACE 4、PC 5和PC 7）的潜力。这些结果不仅提供了深入了解前蛋白转化酶家族中酶功能的分子进化，而且还将有助于前蛋白转化酶功能冗余的研究和治疗应用的开发。
Proprotein convertases are enzymes that proteolytically cleave protein precursors in the secretory pathway to yield functional proteins. Seven mammalian subtilisin/Kex2p-like proprotein convertases have been identified: furin, PC1, PC2, PC4, PACE4, PC5 and PC7. The binding pockets of all seven proprotein convertases are evolutionarily conserved and highly similar. Among the seven proprotein convertases, the furin cleavage site motif has recently been characterized as a 20-residue motif that includes one core region P6-P2´ inside the furin binding pocket. This study extended this information by examining the 3D structural environment of the furin binding pocket surrounding the core region P6-P2´ of furin substrates. The physical properties of mutations in the binding pockets of the other six mammalian proprotein convertases were compared. The results suggest that: 1) mutations at two positions, Glu230 and Glu257, change the overall density of the negative charge of the binding pockets, and govern the substrate specificities of mammalian proprotein convertases; 2) two proprotein convertases (PC1 and PC2) may have reduced sensitivity for positively charged residues at substrate position P5 or P6, whereas the substrate specificities of three proprotein convertases (furin, PACE4, and PC5) are similar to each other. This finding led to a novel design of a short peptide pattern for small molecule inhibitors: [K/R]-X-V-X-K-R. Compared with the widely used small molecule dec-RVKR-cmk that inhibits all seven proprotein convertases, a finely-tuned derivative of the short peptide pattern [K/R]-X-V-X-K-R may have the potential to more effectively inhibit five of the proprotein convertases (furin, PC4, PACE4, PC5 and PC7) compared to the remaining two (PC1 and PC2). The results not only provide insights into the molecular evolution of enzyme function in the proprotein convertase family, but will also aid the study of the functional redundancy of proprotein convertases and the development of therapeutic applications.