12-Dithiolane 改性自组装肽的合成与表征
Summary
一种合成 12-dithiolane 修饰肽的协议, 以及肽自组装产生的超分子结构的表征。
Abstract
本报告的重点是合成一个 n-终点 12-dithiolane 修饰自组装肽, 并描述了由此产生的自组装超分子结构。合成路线利用固相肽合成与 dithiolane 前体分子的树脂耦合, 3-(acetylthio)-2-(acetylthiomethyl) 丙酸, 和微波辅助硫代乙酸脱的肽从树脂最终裂解前的 N 终点, 产生 12-dithiolane 修饰肽。用高效液相色谱 (HPLC) 纯化 12-dithiolane 肽, 从 Aβ肽与阿尔茨海默病相关的核核中提取, 该肽显示为自组装成交叉β淀粉样纤维。介绍了用傅里叶变换红外光谱 (IR)、环形二色谱光谱 (CD) 和透射电镜 (TEM) 表征淀粉样纤维的协议。采用 12-dithiolane 基团对特征自组装肽进行 n-末端修饰的方法, 现在可以作为模型系统来开发装配后的修改策略, 并探讨动态共价键化学在超分子肽碳纤维表面。
Introduction
固相肽合成中的健壮肽键形成化学和控制序列长度和成分的能力使自组装成超分子结构的多肽成为一个研究领域。控制和稳定肽自组装结构的因素, 包括侧链空间和静电相互作用, 氢键和疏水效应1, 作为一套设计规则。随着对这些基本设计规则的研究继续进展, 肽自组装的逻辑下一步包括扩大肽基结构和功能的多样性。自组装多肽是一种多功能生物材料, 通过调整肽序列或装配条件2、3、4, 为许多医学应用而使用, 发展战略为对多肽纳米纤维5、6、7、8、9的组装后的修改仍然是一个相对未开发的领域。
超分子结构表面的动态二硫化物交换和硫醇化学是一个有潜力产生新的和功能性生物材料的领域。12-dithiolane 基团 (通常是硫辛酸 (la) 或 asparagusic 酸 (aa) 的衍生物) 在脂质体系统10、11、嵌段共聚物12、13和组织锚在表面14,15。在这里, 我们报告的合成和表征的自组装肽来源于与阿尔茨海默病相关的 Aβ肽的核核, 在 N 终点被修改 12-dithiolane 功能组16, 17。由此产生的超分子纤维作为实验平台, 研究了淀粉样纤维的超分子表面的二硫交换和硫醇反应性.18。
Protocol
1. 12-Dithiolane 改性肽的合成与纯化 dithiolane 前体的合成, 3-(acetylthio)-2-(acetylthiomethyl) 丙酸19。 添加1克 3-溴-2-(溴甲基) 丙酸 (1 equiv) 溶解在极小量的1米氢氧化钠 (约4毫升) 到一个25毫升的圆形底部反应瓶搅拌在55摄氏度。在氮气气氛下, 将反应瓶密封在一个隔膜和地方。 在4毫升的去离子水和3毫升的2米硫酸 (H2,4) 中, 制备含有1.49 克?…
Representative Results
除了最初一步合成的 dithiolane 前体分子, 其余的 12-dithiolane 改良肽合成发生在坚实的支持 (图 1A)。3-溴-2-溴甲基丙酸转化为 3-(acetylthio)-2-(acetylthiomethyl) 丙酸, dithiolane 前驱体, 由1H 和13C 核磁共振 (图 1B和c) 确认, 然后再耦合到自由肽的 n-末端胺仍然在树脂。用氢氧化铵脱硫代乙酸到硫醇, 在 12-dithiolane ?…
Discussion
本文讨论了 n-端 12-dithiolane 修饰自组装肽的合成和纯化的细节, 以及由此产生的超分子结构的特性。本报告所报道的 12-dithiolane 肽的合成具有优点, 包括一步法合成制备 dithiolane 前驱体、3-(acetylthio)-2-(acetylthiomethyl) 丙酸, 以及在树脂上微波脱反应的前体硫代乙酸保护基团, 利用氢氧化铵作为一种较安全的替代物, 脱29的毒性肼, 产生氧化的 12-dithiolane 基团。12-dithiolane 肽 (<strong class="x…
Disclosures
The authors have nothing to disclose.
Acknowledgements
作者感谢 Scanley 博士为她的技术培训和帮助使用 TEM 在康涅狄格州立大学 (CSCU) 纳米技术中心和 Ishita 博士 Mukerji 在卫斯理大学访问她的 CD分 光 光度计。所报告的工作部分是在美国宇航局康涅狄格州空间赠款联合会的费尔菲尔德大学科学研究所和国家科学基金会 CHE-1624774 的资助下进行的。
Materials
| Rink amide MBHA resin, high load | Gyros Protein Technologies | RAM-5-HL | Avoid contact with skin and eyes; do not inhale |
| N,N-Dimethylformamide | Fisher Scientific | D119-4 | Flammable liquid and vapor; irritating to eyes and skin; Use personal protective equipment; keep away from open flame |
| Fmoc-L-Val-OH | Gyros Protein Technologies | FLA-25-V | Wear personal protective equipment; do not inhale |
| Fmoc-L-Leu-OH | Gyros Protein Technologies | FLA-25-L | Wear personal protective equipment; do not inhale |
| Fmoc-L-Lys(Boc)-OH | Gyros Protein Technologies | FLA-25-KBC | Wear personal protective equipment; do not inhale |
| Fmoc-L-Phe-OH | Gyros Protein Technologies | FLA-25-F | Wear personal protective equipment; do not inhale |
| Fmoc-L-Ala-OH | Gyros Protein Technologies | FLA-25-A | Wear personal protective equipment; do not inhale |
| Fmoc-L-Gln(Trt)-OH | Gyros Protein Technologies | FLA-25-QT | Wear personal protective equipment; do not inhale |
| N,N,N′,N′-Tetramethyl-O-(1H-benzotriazol-1-yl)uronium hexafluorophosphate | Gyros Protein Technologies | 26432 | Causes skin, eye and respiratory irritation; do not inhale; use under hood or in well ventilated area |
| 0.4 M N-methylmorpholine in DMF | Gyros Protein Technologies | PS3-MM-L | highly flammable; wear personal protective equipment; keep away from heat and keep container tightly closed; do not inhale or swallow; wash skin thoroughly after handling |
| 20% piperidine in DMF | Gyros Protein Technologies | PS3-PPR-L | Causes severe eye and skin burns; Flammable Liquid and vapor; Do not inhale |
| dichloromethane | Fisher Scientific | D37-4 | May cause cancer; Do not inhale; Wear personal protective equipment; use under hood only; if contacted rise with water for at least 15 minutes and obtain medical attention |
| acetonitrile | Fisher Scientific | A998-4 | Flammable; irritating to eyes; Use personal protective equipment; Use only under a fume hood; keep away from open flame or hot surface; if contacted rinse wiith water for at least 15 minutes and obtain medical attention |
| trifluoroacetic acid | Fisher Scientific | A116-50 | Causes severe burns; do not inhale; harmful to aquatic life; use personal protective equipment; use only under fume hood; if contacted rinse with water for at least 15 minutes and obain immediate medical attention |
| 4% uranyl acetate | Electron Microscopy Sciences | 22400-4 | Do not inhale; harmful to aquatic life |
| 4-(2-Hydroxyethyl)piperazine-1-ethanesulfonic acid | Acros Organics | AC172571000 | Do not inhale; use outdoors or in well-ventilated area |
| nitrogen Gas | TechAir | Contents under pressure, may explode if heated | |
| 3-bromo-2-(bromomethyl)propionic acid | Alfa Aesar | AAA1963014 | Do not inhale; causes irritation to skin and eyes; corrosive |
| sodium hydroxide | Fisher Scientific | S318-100 | Use personal protective equipment; use only under fume hood; if contact rinse area for at least 15 minutes and obtain medical attention |
| potassium thioacetate | Acros Organics | AC221300250 | Causes skin and eye irritation; do not inhale; use personal protective equipment |
| sulfuric acid | Fisher Scientific | SA213 | Causes burns; keep away from water; keep away from combustible material; do not inhale; use personal protective equipment; if contact rinse area for at least 15 minutes and obtain medical attention |
| chloroform-d | Acros Organics | AC320690075 | Possible cancer hazard; irritating to skin and eyes; do not inhale; Use personal protective equipment; use only under fume hood; If contact rinse area for at least 15 minutes and obtain medical attention |
| chloroform | Fisher Scientific | C298-4 | Possible cancer hazard; irritating to skin and eyes; do not inhale; Use personal protective equipment; use only under fume hood; If contact rinse area for at least 15 minutes and obtain medical attention |
| N,N-diisopropylethylamine | Acros Organics | AC367841000 | Highly flammable; harmful to aquatic life; wear personal protective equipment; do not swallow |
| ammonium hydroxide | Fisher Scientific | A669S-500 | Corrosive; do not inhale |
| methanol | Fisher Scientific | A452-4 | Flammable liquid and vapor; use personal protective equipment; do not inhale; If contact rinse area for at least 15 minutes and obtain medical attention |
| triisopropylsilane | Sigma Aldrich | 233781 | Flammable; use personal proctective safety equipment; keep container tightly closed |
| diethyl ether | Fisher Scientific | E138-1 | Extremely flammable; Irritating to skin and eyes; Use personal protective equipment |
| 2,5-dihydroxybenzoic acid | Sigma Aldrich | 39319-10x10MG-F | do not inhale; irritating to skin and eyes |
| alpha-cyano-4-hydroxycinnamic acid | Alfa Aesar | AAJ67635EXK | |
| c18 zip-tip | Millipore | ZTC18S096 | |
| tris(2-carboxyethyl) phospine hydrochloride | Thermo Scientific | PI20490 | |
| silica gel 60 F254 coated aluminum-backed TLC sheets | EMD Millipore | 1.05549.0001 | |
| Thin walled Precision NMR tubes | Bel-Art | 663000585 | 5mm O.D. |
| All-plastic Norm-Ject syringes | Air Tite | AL10 | |
| single-use needle | BD PrecisionGlide | BD 305185 | used needles get disposed on in sharps waste container |
| disposable fritted syringe | Torviq | SF1000LL | 10mL fritted syringes were used in the report, but larger syringes are avaibale if needed for larger scale synthesis. |
| carbon grid | Ted Pella, Inc. | CF200-CU | Make sure to prepare samples and staining on the carbon grid side, not the shiny copper side of grid |
| self-closing tweezers | Electron Microscopy Sciences | 78318-3X | very sharp tips, length: 120 mm |
| 0.1 mm short path length cell | Starna Cells, Inc. | 20/C-Q-0.1 | Fragile |
| 10mL Vessel Caps | CEM | 909210 | |
| 10mL Pressure Vessels | CEM | 908035 | |
| Aeris Semi-Prep HPLC column | Phenomenex | 00F-4632-N0 | 150 x 10mm |
| cell holder | Starna Cells, Inc. | CH-2049 | Needed when using short pathlength cells |
| PS3 peptide synthesizer | Gyros Protein Technologies | ||
| DiscoverSP Microwave Reactor | CEM | ||
| centrifuge | HERMLE | Z 206 A | used a fixed 6×50 mL rotor |
| HPLC | Shimadzu | UV Detector | |
| nuclear magnetic resonance spectrometer | Avance, Bruker | 300 MHz | |
| MALDI-TOF mass spectrometer | Axima Confidence, Shimadzu | ||
| lyophilizer | Millrock Technology | BT85A | |
| Fourier-Transform Infrared Spectrometer | Alpha Tensor, Bruker | ||
| Transmission Electron Microscope | Tecnai Spirit, FEI | Used with Gatan Orius Fiberoptic CCD digital camera. Accessed at CSCU Center for Nanotechnology | |
| Circular Dichroism Spectropolarimeter | J-810, JASCO | Used with a six-cell Peltier temperature controller. Accessed at Wesleyan University. |
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Cite This Article
Neves, R., Stephens, K., Smith-Carpenter, J. E. Synthesis and Characterization of 1,2-Dithiolane Modified Self-Assembling Peptides. J. Vis. Exp. (138), e58135, doi:10.3791/58135 (2018).