Small-molecule control of neurotransmitter sulfonation.
Small-molecule control of neurotransmitter sulfonation.
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DOI：
10.1074/jbc.ra120.015177
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发表时间：
2021-01
期刊：
影响因子：
--
通讯作者：
Leyh TS
中科院分区：
文献类型：
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作者：
Cook I;Cacace M;Wang T;Darrah K;Deiters A;Leyh TS
控制大脑突触中未改变的血清素水平是治疗重度抑郁症的主要目标，这种疾病折磨着世界上20%的人口。大约60%的患者对一线治疗反应不佳，因此需要寻求新的治疗策略。为此，我们构建了人胞质硫转移酶1A3 （SULT1A3）的异构体特异性抑制剂，该异构体负责细胞外脑液中80%的5 -羟色胺磺化。该抑制剂设计包括一个核心环结构，将抑制剂固定在位于活性位点外的SULT1A3特异性结合口袋中，以及一个侧链，作为锁存器，通过固定SULT1A3活性位点帽来抑制转换。这些抑制剂是变抗性的，它们以纳摩尔亲和力结合，对1A3亚型具有高度特异性。闩锁的帽稳定效应可以精确地计算和预测到整个帽延伸到周围的蛋白质。自由能相关性表明，饱和抑制剂的抑制率随帽稳定性呈线性变化——相关性是线性的，因为催化循环的限速步骤，核苷酸释放，与开帽形式的酶的比例呈线性关系。利用人乳腺上皮细胞系研究了抑制剂在培养细胞中的效果，该细胞系表达SULT1A3的水平与神经元中的水平相当。这些抑制剂在离体和体外研究中表现相似；因此，SULT1A3的转换现在可以在人类细胞中以同型特异性的方式被有效地抑制。
Controlling unmodified serotonin levels in brain synapses is a primary objective when treating major depressive disorder—a disease that afflicts ∼20% of the world’s population. Roughly 60% of patients respond poorly to first-line treatments and thus new therapeutic strategies are sought. To this end, we have constructed isoform-specific inhibitors of the human cytosolic sulfotransferase 1A3 (SULT1A3)—the isoform responsible for sulfonating ∼80% of the serotonin in the extracellular brain fluid. The inhibitor design includes a core ring structure, which anchors the inhibitor into a SULT1A3-specific binding pocket located outside the active site, and a side chain crafted to act as a latch to inhibit turnover by fastening down the SULT1A3 active-site cap. The inhibitors are allosteric, they bind with nanomolar affinity and are highly specific for the 1A3 isoform. The cap-stabilizing effects of the latch can be accurately calculated and are predicted to extend throughout the cap and into the surrounding protein. A free-energy correlation demonstrates that the percent inhibition at saturating inhibitor varies linearly with cap stabilization — the correlation is linear because the rate-limiting step of the catalytic cycle, nucleotide release, scales linearly with the fraction of enzyme in the cap-open form. Inhibitor efficacy in cultured cells was studied using a human mammary epithelial cell line that expresses SULT1A3 at levels comparable with those found in neurons. The inhibitors perform similarly in ex vivo and in vitro studies; consequently, SULT1A3 turnover can now be potently suppressed in an isoform-specific manner in human cells.