Browsing by Author "Liao, Jiunn-Der"

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Mutated Human P-Selectin Glycoprotein Ligand-1 and Viral Protein-1 of Enterovirus 71 Interactions on Au Nanoplasmonic Substrate for Specific Recognition by Surface-Enhanced Raman Spectroscopy
(2020-04-01)
Sivashanmugan, Kundan
;
Lee, Han
;
Liao, Jiunn-Der
;
Wang, Chen-Chu
;
Lin, Chen-Hsueh
Protein tyrosine sulfation is a common post-translational modification that stimulates intercellular or extracellular protein-protein interactions and is responsible for various important biological processes, including coagulation, inflammation, and virus infections. Recently, human P-selectin glycoprotein ligand-1 (PSGL-1) has been shown to serve as a functional receptor for enterovirus 71 (EV71). It has been proposed that the capsid viral protein VP1 of EV71 is directly involved in this specific interaction with sulfated or mutated PSGL-1. Surface-enhanced Raman spectroscopy (SERS) is used to distinguish PSGL-1 and VP1 interactions on an Au nanoporous substrate and identify specific VP1 interaction positions of tyrosine residue sites (46, 48, and 51). The three tyrosine sites in PSGL-1 were replaced by phenylalanine (F), as determined using SERS. A strong phenylalanine SERS signal was obtained in three regions of the mutated protein on the nanoporous substrate. The mutated protein positions at (51F) and (48F, 51F) produced a strong SERS peak at 1599-1666 cm(-1), which could be related to a binding with the mutated protein and anti-sulfotyrosine interactions on the nanoporous substrate. A strong SERS effect of the mutated protein and VP1 interactions appeared at (48F), (51F), and (46F, 48F). In these positions, there was less interaction with VP1, as indicated by a strong phenylalanine signal from the mutated protein.
Spatially reinforced Au nano-cavities as a reaction nano-reservoir for trace analysis of DNA hybridization
(2014-02-01)
Yao, Chih-Kai
;
Liao, Jiunn-Der
;
Lin, Chih-Heng
;
Yang, Yuh-Shyong
;
Yu, Sheng-Hong
Spatially reinforced Au nano-cavities (SR-nAu) with reduced tip-to-tip displacement create strongly localized surface plasmon resonance by Raman scattering. Within SR-nAu, the nano-cavity structure with high aspect ratio was optimized as the nano-reservoir for the distinction of DNA hybridization responses from specific DNA sequences of Avian influenza virus. In the nano-reservoir, the suspended or immobilized probe, its complementary and noncomplementary target sequences were characterized at very low concentration through enhanced Raman spectra. The presence of Raman shift at 738 cm(-1), the characteristic breathing mode of thymine, and the change of relative peaks intensity at 1603 and 1554 cm(-1) before and after hybridization were particularly taken as the major indications to validate the match or mismatch state of DNA sequences. Through a labeling-free means, and from the evidence provided by specific complementary and noncomplementary DNA sequences, the recognition capability of nano-reservoir can be down to subnano-molar concentration (10(-10) M). (C) 2013 Elsevier B.V. All rights reserved.
Specific Unbinding Forces Between Mutated Human P-Selectin Glycoprotein Ligand-1 and Viral Protein-1 Measured Using Force Spectroscopy
(2017-11-02)
Wang, Chen-Chu
;
Siyashanmugan, Kundan
;
Chen, Chung-Ku
;
Hong, Jian-Ren
;
Sung, Wei-I
Protein tyrosine sulfation (PTS) is a key modulator of extracellular protein protein interaction (PPI), which regulates principal biological processes. For example, the capsid protein VP1 of enterovirus 71 (EV71) specifically interacts with sulfated P-selectin glycoprotein ligand-1 (PSGL-1) to facilitate virus invasion. Currently available methods cannot be used to directly observe PTS-induced PPI. In this study, atomic force microscopy was used to measure the interaction between sulfated or mutated PSGL-1 and VP1. We found that the binding strength increased by 6.7-fold following PTS treatment on PSGL-1 with a specific antisulfotyrosine antibody. Similar results were obtained when the antisulfotyrosine antibody was replaced with the VP1 protein of EV71; however, the interaction forces of VP1 were only approximately one-third of those of the antisulfotyrosine antibody. We also found that PTS on the tyrosine-51 residue of glutathione S-transferases fusion-PSGL-1 was mainly responsible for the PTS-induced PPI. Our results contribute to the fundamental understanding of PPI regulated through PTS.