Fluorescent and Photosensitizing Conjugates of Cell-Penetrating Peptide TAT(47-57): Design, Microwave-Assisted Synthesis at 60 degrees C, and Properties

Author(s)

Okuda-Shinagawa, Nancy M. ^[1] ; Moskalenko, Yulia E. ^[1] ; Junqueira, Helena C. ^[1] ; Baptista, Mauricio S. ^[1] ; Marques, Carlos M. ^{[1, 2]} ; Teresa Machini, M. ^[1]

Affiliation

^[1] Univ Sao Paulo, Dept Biochem, Inst Chem, Ave Prof Lineu Prestes, 748, Cidade Univ, BR-05508000 Sao Paulo, SP - Brazil

^[2] Univ Strasbourg, Inst Charles Sadron, CNRS UPR22, 23, Rue Loess, BP 84047, F-67034 Strasbourg 2 - France

• Document type: Journal article
• Source: ACS OMEGA; v. 2, n. 11, p. 8156-8166, NOV 2017.
• Web of Science Citations: 0

Abstract

Conjugates based on cell-penetrating peptides (CPPs) are scientifically relevant owing to their structural complexity; their ability to enter cells and deliver drugs, labels, antioxidants, bioactive compounds, or DNA fragments; and, consequently, their potential for application in research and biomedicine. In this study, carboxyamidated fluorescently labeled conjugates FAM-GG-TAT(47-57)-NH2 and FAMPEG(6)-TAT( 47-57)-NH2 and photosensitizer-labeled conjugate Chk-PEG(6)-TAT(47-57)-NH2 {[}where TAT(47-57) is the CPP, 5(6)-carboxyfluorescein is the (FAM) fluorophore, chlorin k (Chk) is the photosensitizer, and the dipeptide glycyl-glycine (GG) or hexaethylene glycol (PEG(6)) is the spacer] were originally designed, prepared, and fully characterized. Practically, all chemical reactions of the synthetic steps (peptide synthesis, spacer incorporation, and conjugation) were microwaveassisted at 60 degrees C using optimized protocols to give satisfying yields and high-quality products. Detailed analyses of the conjugates using spectrofluorimetry and singlet oxygen detection showed that they display photophysical properties typical of FAM or Chk. Anticandidal activity assays showed that not only this basic property of TAT(47-57) was preserved in the conjugates but also that the minimal inhibitory concentration was slightly reduced for cells incubated with PS-bearing conjugate Chk-PEG(6)-TAT(47-57)NH2. Overall, these results indicated that the synthetic approach on-resin assisted by microwaves at 60 degrees C is simple, straightforward, selective, metal-free, sufficiently fast, cleaner, and more cost-effective than those previously used for preparing this type of macromolecule. Furthermore, such new data show that microwaves at 60 degrees C and/or conjugation did not harm the integrity of the conjugates' constituents. Therefore, FAM-GG-TAT(47-57)-NH2, FAM-PEG(6)-TAT(47-57)-NH2, and Chk-PEG(6)TAT( 47-57)-NH2 have high potential for practical applications in biochemistry, biophysics, and therapeutics. (AU)

• FAPESP's process: 13/07937-8 - Redoxome - Redox Processes in Biomedicine
• Grantee: Ohara Augusto
• Support Opportunities: Research Grants - Research, Innovation and Dissemination Centers - RIDC
• FAPESP's process: 15/07508-5 - The influence of photo-induced oxidation on peptide-membrane interactions
• Grantee: Mauricio da Silva Baptista
• Support Opportunities: Research Grants - Visiting Researcher Grant - International