Hydrogen Bonding Compensation on the Convex Solvent-Exposed Helical Face of IA 3 , an Intrinsically Disordered Protein
Hydrogen Bonding Compensation on the Convex Solvent-Exposed Helical Face of IA 3 , an Intrinsically Disordered Protein
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本质无序蛋白质 IA 3 暴露于溶剂的凸螺旋面上的氢键补偿
DOI：
10.1021/acs.biochem.3c00169
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发表时间：
2023
期刊：
影响因子：
2.9
通讯作者：
Fanucci, Gail E.
中科院分区：
文献类型：
--
作者：
Dunleavy, Katie M.;Oi, Collin;Li, Tianyan;Secunda, Andrew;Jaufer, Afnan M.;Zhu, Yinlu;Friedman, Lee;Kim, Alexander;Fanucci, Gail E.
SaccharomycesParaeIA 3是一种68个氨基酸的酵母蛋白酶A（YPRA）抑制剂，其特征是在溶液中呈无规卷曲，当与YPRA结合时，其2-32位残基折叠成N-末端两亲性α螺旋，而33-68位残基在晶体复合物中未被解析。圆二色性（CD）光谱的结果表明，氨基酸取代，消除内观察到的N-末端结构域（NTD）的IA 3-YPRA晶体复合物的亲水性面内的氢键相互作用减少2，2，2-三氟乙醇（TFE）诱导的溶液中的螺旋转变。虽然几乎所有的取代减少了TFE诱导的螺旋度相比，野生型（WT），每个构建体都保留了螺旋特性的存在下，30%（v/v）的TFE和保留在TFE的情况下的障碍。8种不同的放线菌的NTD具有几乎相同的氨基酸序列，表明IA 3的NTD在与YPRA结合和存在TFE时可能高度进化为采用螺旋折叠，但在溶液中保持非结构化。只有一个天然氨基酸取代内的溶剂暴露面的NTD的IA 3诱导的TFE-螺旋大于WT序列的探索。然而，通过含有乙酰胺侧链的氮氧自旋标记物对半胱氨酸进行化学修饰确实增强了TFE诱导的螺旋度。这一发现表明，非天然氨基酸，可以增加氢键或通过侧链相互作用改变水化可能是重要的考虑时，合理设计具有不同的生物技术应用的内在无序蛋白质（IDP）。
Saccharomyces cerevisiaeIA3is a 68 amino acid peptide inhibitor of yeast proteinase A (YPRA) characterized as a random coil when in solution, folding into an N-terminal amphipathic alpha helix for residues 2–32 when bound to YPRA, with residues 33–68 unresolved in the crystal complex. Circular dichroism (CD) spectroscopy results show that amino acid substitutions that remove hydrogen-bonding interactions observed within the hydrophilic face of the N-terminal domain (NTD) of IA3-YPRA crystal complex reduce the 2,2,2-trifluoroethanol (TFE)-induced helical transition in solution. Although nearly all substitutions decreased TFE-induced helicity compared to wild-type (WT), each construct did retain helical character in the presence of 30% (v/v) TFE and retained disorder in the absence of TFE. The NTDs of 8 differentSaccharomycesspecies have nearly identical amino acid sequences, indicating that the NTD of IA3may be highly evolved to adopt a helical fold when bound to YPRA and in the presence of TFE but remain unstructured in solution. Only one natural amino acid substitution explored within the solvent-exposed face of the NTD of IA3induced TFE-helicity greater than the WT sequence. However, chemical modification of a cysteine by a nitroxide spin label that contains an acetamide side chain did enhance TFE-induced helicity. This finding suggests that non-natural amino acids that can increase hydrogen bonding or alter hydration through side-chain interactions may be important to consider when rationally designing intrinsically disordered proteins (IDPs) with varied biotechnological applications.