在本實驗室的微陣列晶片實驗中，修飾有長氟碳鏈的脯胺酸多肽已被開發用於氟修飾晶片上輔助調控配基間距，而在研究當中，我們發現不同數量的全氟己醯胺基對於脯胺酸多肽的構形有很大的影響。於此，我們合成出4R位向修飾有乙醯胺基、三氟乙醯胺基、全氟己醯胺基的脯胺酸，並以固相多肽合成的順序來控制非天然脯胺酸的位置，藉此合成了修飾有長度、數量、位向不同的氟碳鏈官能基團的脯胺酸多肽，再利用圓二色光譜比較多肽分子在水與正丙醇溶劑下的構形差異。同時，我們也合成出氮端修飾有乙醯官能基團的非天然脯胺酸多肽，藉此探討氟化脯胺酸多肽的帶電荷性對於脯胺酸螺旋構形的影響，並與文獻當中的天然脯胺酸多肽做比較。

Perfluoroalkyl-modified polyproline peptides have been exploited as a molecular scaffold to control ligand spacing in a fluorous microarray. In the previous work, it was found that the number of perfluoroalkyl groups on a polyproline peptide has significant effects on the helix conformation. To investigate the contribution of such fluorous groups, we designed proline derivatives with acetamido trifluoroacetamido or perfluorohexanamido groups at the 4R position of prolines. By controlling sequences during solid-phase peptide synthesis, the numbers, types and locations of these non-natural on polyproline peptides can be manipulated to allow systematic analysis of the helix conformation. In addition, we prepared the corresponding polyproline peptides with acetyl group at the N-terminus to investigate the contribution of the terminal charge of fluorinated polyproline peptides on their helical stuctures.

1. Lee, Y. C.; Lee, R. T., Carbohydrate-Protein Interactions: Basis of Glycobiology. Acc. Chem. Res 1995, 28 (8), 321-327.
2. Mammen, M.; Choi, S.-K.; Whitesides, G. M., Polyvalent Interactions in Biological Systems: Implications for Design and Use of Multivalent Ligands and Inhibitors. Angew. Chem. Int. Ed 1998, 37 (20), 2754-2794.
3. Blixt, O.; Head, S.; Mondala, T.; Scanlan, C.; Huflejt, M. E.; Alvarez, R.; Bryan, M. C.; Fazio, F.; Calarese, D.; Stevens, J.; Razi, N.; Stevens, D. J.; Skehel, J. J.; van Die, I.; Burton, D. R.; Wilson, I. A.; Cummings, R.; Bovin, N.; Wong, C.-H.; Paulson, J. C., Printed covalent glycan array for ligand profiling of diverse glycan binding proteins. Proc. Natl. Acad. Sci. U.S.A. 2004, 101 (49), 17033.
4. Chevolot, Y.; Bouillon, C.; Vidal, S.; Morvan, F.; Meyer, A.; Cloarec, J.-P.; Jochum, A.; Praly, J.-P.; Vasseur, J.-J.; Souteyrand, E., DNA-Based Carbohydrate Biochips: A Platform for Surface Glyco-Engineering. Angew. Chem. Int. Ed 2007, 46 (14), 2398-2402.
5. Uttamchandani, M.; Walsh, D. P.; Yao, S. Q.; Chang, Y.-T., Small molecule microarrays: recent advances and applications. Curr. Opin. Chem. Biol. 2005, 9 (1), 4-13.
6. Lin, T.-H.; Lin, C.-H.; Liu, Y.-J.; Huang, C. Y.; Lin, Y.-C.; Wang, S.-K., Controlling Ligand Spacing on Surface: Polyproline-Based Fluorous Microarray as a Tool in Spatial Specificity Analysis and Inhibitor Development for Carbohydrate–Protein Interactions. ACS Appl. Mater.Interfaces 2017, 9 (48), 41691-41699.
7. Cametti, M.; Crousse, B.; Metrangolo, P.; Milani, R.; Resnati, G., The fluorous effect in biomolecular applications. Chem. Soc. Rev. 2012, 41 (1), 31-42.
8. Shah, P.; Westwell, A. D., The role of fluorine in medicinal chemistry. J. Enzyme Inhib. Med. Chem. 2007, 22 (5), 527-540.
9. Zhang, W.; Lu, Y., Automation of Fluorous Solid-Phase Extraction for Parallel Synthesis. J. Comb. Chem. 2006, 8 (6), 890-896.
10. Zhang, W.; Lu, Y.; Nagashima, T., Plate-to-Plate Fluorous Solid-Phase Extraction for Solution-Phase Parallel Synthesis. J. Comb. Chem. 2005, 7 (6), 893-897.
11. Inoue, M.; Sumii, Y.; Shibata, N., Contribution of Organofluorine Compounds to Pharmaceuticals. ACS Omega 2020, 5 (19), 10633-10640.
12. Böhm, H.-J.; Banner, D.; Bendels, S.; Kansy, M.; Kuhn, B.; Müller, K.; Obst-Sander, U.; Stahl, M., Fluorine in Medicinal Chemistry. ChemBioChem 2004, 5 (5), 637-643.
13. Park, B. K.; Kitteringham, N. R.; O'Neill, P. M., Metabolism of Fluorine-Containing Drugs. Annu. Rev. Pharmacol. Toxicol. 2001, 41 (1), 443-470.
14. Kiss, L. E.; Kövesdi, I.; Rábai, J., An improved design of fluorophilic molecules: prediction of the ln P fluorous partition coefficient, fluorophilicity, using 3D QSAR descriptors and neural networks. J. Fluor. Chem. 2001, 108 (1), 95-109.
15. Zhang, W., Highlights of Applications in Synthesis and Catalysis: 10.5 Fluorous Protecting Groups and Tags. Handbook of Fluorous Chemistry 2004, 222-236.
16. Curran, D. P., Separations with Fluorous Silica Gel and Related Materials. Handbook of Fluorous Chemistry 2004, 101-127.
17. Curran, D. P.; Hadida, S.; He, M., Thermal Allylations of Aldehydes with a Fluorous Allylstannane. Separation of Organic and Fluorous Products by Solid Phase Extraction with Fluorous Reverse Phase Silica Gel. J. Org. Chem. 1997, 62 (20), 6714-6715.
18. Simonelli, B.; Orlandi, S.; Benaglia, M.; Pozzi, G., New Perfluoroalkyl-Substituted Bisoxazolines as Chiral Ligands in Asymmetric CuII-Catalyzed Reactions. Eur. J. Org. Chem. 2004, 2004 (12), 2669-2673.
19. Curran, D. P.; Amatore, M.; Guthrie, D.; Campbell, M.; Go, E.; Luo, Z., Synthesis and Reactions of Fluorous Carbobenzyloxy (FCbz) Derivatives of α-Amino Acids. J. Org. Chem. 2003, 68 (12), 4643-4647.
20. Wende, M.; Meier, R.; Gladysz, J. A., Fluorous Catalysis without Fluorous Solvents:  A Friendlier Catalyst Recovery/Recycling Protocol Based upon Thermomorphic Properties and Liquid/Solid Phase Separation. J. Am. Chem. Soc. 2001, 123 (46), 11490-11491.
21. Marsh, E. N. G., Fluorinated Proteins: From Design and Synthesis to Structure and Stability. Acc. Chem. Res 2014, 47 (10), 2878-2886.
22. Park, S.; Gildersleeve, J. C.; Blixt, O.; Shin, I., Carbohydrate microarrays. Chem. Soc. Rev. 2013, 42 (10), 4310-4326.
23. Harris, L. G.; Schofield, W. C. E.; Doores, K. J.; Davis, B. G.; Badyal, J. P. S., Rewritable Glycochips. J. Am. Chem. Soc. 2009, 131 (22), 7755-7761.
24. Sun, X.-L.; Stabler, C. L.; Cazalis, C. S.; Chaikof, E. L., Carbohydrate and Protein Immobilization onto Solid Surfaces by Sequential Diels−Alder and Azide−Alkyne Cycloadditions. Bioconjugate Chem. 2006, 17 (1), 52-57.
25. Galanina, O. E.; Mecklenburg, M.; Nifantiev, N. E.; Pazynina, G. V.; Bovin, N. V., GlycoChip: multiarray for the study of carbohydrate-binding proteins. Lab Chip 2003, 3 (4), 260-265.
26. Ko, K.-S.; Jaipuri, F. A.; Pohl, N. L., Fluorous-Based Carbohydrate Microarrays. J. Am. Chem. Soc. 2005, 127 (38), 13162-13163.
27. Mamidyala, S. K.; Ko, K.-S.; Jaipuri, F. A.; Park, G.; Pohl, N. L., Noncovalent fluorous interactions for the synthesis of carbohydrate microarrays. J. Fluor. Chem. 2006, 127 (4), 571-579.
28. Chen, G.-S.; Pohl, N. L., Synthesis of Fluorous Tags for Incorporation of Reducing Sugars into a Quantitative Microarray Platform. Org. Lett. 2008, 10 (5), 785-788.
29. Jaipuri, F. A.; Collet, B. Y. M.; Pohl, N. L., Synthesis and Quantitative Evaluation of Glycero-D-manno-heptose Binding to Concanavalin A by Fluorous-Tag Assistance. Angew. Chem. Int. Ed 2008, 47 (9), 1707-1710.
30. Vegas, A. J.; Bradner, J. E.; Tang, W.; McPherson, O. M.; Greenberg, E. F.; Koehler, A. N.; Schreiber, S. L., Fluorous-Based Small-Molecule Microarrays for the Discovery of Histone Deacetylase Inhibitors. Angew. Chem. Int. Ed 2007, 46 (42), 7960-7964.
31. Flynn, G. E.; Withers, J. M.; Macias, G.; Sperling, J. R.; Henry, S. L.; Cooper, J. M.; Burley, G. A.; Clark, A. W., Reversible DNA micro-patterning using the fluorous effect. Chem. Commun. 2017, 53 (21), 3094-3097.
32. El-Baba, T. J.; Fuller, D. R.; Hales, D. A.; Russell, D. H.; Clemmer, D. E., Solvent Mediation of Peptide Conformations: Polyproline Structures in Water, Methanol, Ethanol, and 1-Propanol as Determined by Ion Mobility Spectrometry-Mass Spectrometry. J. Am. Soc. Mass Spectrom. 2019, 30 (1), 77-84.
33. Kuemin, M.; Engel, J.; Wennemers, H., Temperature-induced transition between polyproline I and II helices: quantitative fitting of hysteresis effects. J. Pept. Sci. 2010, 16 (10), 596-600.
34. Horng, J.-C.; Raines, R. T., Stereoelectronic effects on polyproline conformation. Protein Sci. 2006, 15 (1), 74-83.
35. Stryer, L.; Haugland, R. P., Energy transfer: a spectroscopic ruler. Proc. Natl. Acad. Sci. U.S.A. 1967, 58 (2), 719.
36. Wilhelm, P.; Lewandowski, B.; Trapp, N.; Wennemers, H., A Crystal Structure of an Oligoproline PPII-Helix, at Last. J. Am. Chem. Soc. 2014, 136 (45), 15829-15832.
37. Ruggiero, M. T.; Sibik, J.; Orlando, R.; Zeitler, J. A.; Korter, T. M., Measuring the Elasticity of Poly-l-Proline Helices with Terahertz Spectroscopy. Angew. Chem. Int. Ed 2016, 55 (24), 6877-6881.
38. Kroll, C.; Mansi, R.; Braun, F.; Dobitz, S.; Maecke, H. R.; Wennemers, H., Hybrid Bombesin Analogues: Combining an Agonist and an Antagonist in Defined Distances for Optimized Tumor Targeting. J. Am. Chem. Soc. 2013, 135 (45), 16793-16796.
39. Lewandowska, U.; Zajaczkowski, W.; Pisula, W.; Ma, Y.; Li, C.; Müllen, K.; Wennemers, H., Effect of Structural Modifications on the Self-Assembly of Oligoprolines Conjugated with Sterically Demanding Chromophores. Chem. Eur. J. 2016, 22 (11), 3804-3809.
40. Sato, S.-i.; Kwon, Y.; Kamisuki, S.; Srivastava, N.; Mao, Q.; Kawazoe, Y.; Uesugi, M., Polyproline-Rod Approach to Isolating Protein Targets of Bioactive Small Molecules:  Isolation of a New Target of Indomethacin. J. Am. Chem. Soc. 2007, 129 (4), 873-880.
41. Kuriakose, J.; Hernandez-Gordillo, V.; Nepal, M.; Brezden, A.; Pozzi, V.; Seleem, M. N.; Chmielewski, J., Targeting Intracellular Pathogenic Bacteria with Unnatural Proline-Rich Peptides: Coupling Antibacterial Activity with Macrophage Penetration. Angew. Chem. Int. Ed 2013, 52 (37), 9664-9667.
42. Payette, J. N.; Yamamoto, H., Regioselective and Asymmetric Diels−Alder Reaction of 1- and 2-Substituted Cyclopentadienes Catalyzed by a Brønsted Acid Activated Chiral Oxazaborolidine. J. Am. Chem. Soc. 2007, 129 (31), 9536-9537.
43. Wannere, C. S.; Paul, A.; Herges, R.; Houk, K. N.; Schaefer Iii, H. F.; Von Ragué Schleyer, P., The existence of secondary orbital interactions. J. Comput. Chem. 2007, 28 (1), 344-361.
44. Pandey, A. K.; Naduthambi, D.; Thomas, K. M.; Zondlo, N. J., Proline Editing: A General and Practical Approach to the Synthesis of Functionally and Structurally Diverse Peptides. Analysis of Steric versus Stereoelectronic Effects of 4-Substituted Prolines on Conformation within Peptides. J. Am. Chem. Soc. 2013, 135 (11), 4333-4363.
45. Lin, Y.-J.; Horng, J.-C., Impacts of terminal (4R)-fluoroproline and (4S)-fluoroproline residues on polyproline conformation. Amino Acids 2014, 46 (10), 2317-2324.
46. Billsten, P.; Wahlgren, M.; Arnebrant, T.; McGuire, J.; Elwing, H., Structural Changes of T4 Lysozyme upon Adsorption to Silica Nanoparticles Measured by Circular Dichroism. J. Colloid Interface Sci. 1995, 175 (1), 77-82.
47. Del Villar-Guerra R.; Trent J. O.; Chaires J. B., G-Quadruplex Secondary Structure Obtained from Circular Dichroism Spectroscopy. Angew. Chem. Int. Ed. 2018, 57 (24), 7171-7175.
48. Lamba, J.; Paul, S.; Hasija, V.; Aggarwal, R.; Chaudhuri, T. K., Monitoring protein folding and unfolding pathways through surface hydrophobicity changes using fluorescence and circular dichroism spectroscopy. Biochemistry (Moscow) 2009, 74 (4), 393-398.
49. Zhu, F.; Davies, P.; Thompsett, A. R.; Kelly, S. M.; Tranter, G. E.; Hecht, L.; Isaacs, N. W.; Brown, D. R.; Barron, L. D., Raman Optical Activity and Circular Dichroism Reveal Dramatic Differences in the Influence of Divalent Copper and Manganese Ions on Prion Protein Folding. Biochemistry 2008, 47 (8), 2510-2517.
50. Feng, Y.; Melacini, G.; Taulane, J. P.; Goodman, M., Acetyl-Terminated and Template-Assembled Collagen-Based Polypeptides Composed of Gly-Pro-Hyp Sequences. 2. Synthesis and Conformational Analysis by Circular Dichroism, Ultraviolet Absorbance, and Optical Rotation. J. Am. Chem. Soc. 1996, 118 (43), 10351-10358.
51. Kemp, D. S.; Petrakis, K. S., Synthesis and conformational analysis of cis,cis-1,3,5-trimethylcyclohexane-1,3,5-tricarboxylic acid. J. Org. Chem. 1981, 46 (25), 5140-5143.
52. Kuemin, M.; Schweizer, S.; Ochsenfeld, C.; Wennemers, H., Effects of Terminal Functional Groups on the Stability of the Polyproline II Structure: A Combined Experimental and Theoretical Study. J. Am. Chem. Soc. 2009, 131 (42), 15474-15482.
53. Kakinoki, S.; Hirano, Y.; Oka, M., On the Stability of Polyproline-I and II Structures of Proline Oligopeptides. Polym. Bull. 2005, 53 (2), 109-115.
54. Lin, C.-H.; Wen, H.-C.; Chiang, C.-C.; Huang, J.-S.; Chen, Y.; Wang, S.-K., Polyproline Tri-Helix Macrocycles as Nanosized Scaffolds to Control Ligand Patterns for Selective Protein Oligomer Interactions. Small 2019, 15 (20), 1900561.
55. Merrifield, R. B., Solid Phase Peptide Synthesis. I. The Synthesis of a Tetrapeptide. J. Am. Chem. Soc. 1963, 85 (14), 2149-2154.
56. United state. Environmental Protection Agency. Revised Draft Hazard Assessment of Perfluorooctanoic Acid and Its Salts. Office of Pollution Prevention and Toxics Risk Assessment Division. http://www.fluoridealert.org/wp-content/pesticides/pfoa.epa.nov.4.2002.pdf 4 November 2002.
57. OECD. 2002 Co-operation on Existing Chemicals—Hazard Assessment of Perfluorooctane Sulfonate (PFOS) and Its Salts. https://www.oecd.org/env/ehs/risk-assessment/2382880.pdf Latest update 21 November 2002.