title: Mechanistic study for immobilization of cysteine-labeled oligopeptides on UV-activated surfaces.
abstract: In this study, we report immobilization of cysteine-labeled oligopeptides on UV activated surfaces decorated with N,N-dimethyl-n-octadecyl-3-aminopropyltrimethoxysilyl chloride (DMOAP). Our result shows that cysteine group, regardless of its position in the oligopeptide, is essential for successful immobilization of oligopeptide on the UV-activated surface. A possible reaction mechanism is nucleophilic addition of thiolates to surface aldehyde groups generated during UV activation. By using this technique, we are able to incorporate anchoring points into oligopeptides through cysteine residues. Furthermore, immobilized oligopeptides on the UV-activated surface is very stable even under harsh washing conditions. Finally, we show that an HPQ-containing oligopeptide can be immobilized on the UV-activated surface, but the final surface density and its ability to bind streptavidin are affected by the position of cysteine and HPQ. An oligopeptide with a cysteine at the N-terminus and a HPQ motif at the C-terminus gives the highest binding signal in the streptavidin-binding assay. This result is potentially useful for the development of functional oligopeptide microarrays for detecting target protein molecules.
authors.affiliation: Department of Chemical and Biomolecular Engineering, National University of Singapore, 4 Engineering Drive 4, Singapore 117585, Singapore.
authors.forename: Lian Hao
authors.initials: LH
authors.lastname: Ong
authors.affiliation: Department of Chemical and Biomolecular Engineering, National University of Singapore, 4 Engineering Drive 4, Singapore 117585, Singapore.
authors.forename: Xiaokang
authors.initials: X
authors.lastname: Ding
authors.affiliation: Department of Chemical and Biomolecular Engineering, National University of Singapore, 4 Engineering Drive 4, Singapore 117585, Singapore. Electronic address: cheyk@nus.edu.sg.
authors.forename: Kun-Lin
authors.initials: KL
authors.lastname: Yang
mesh_terms: D003545:Cysteine / Q000737:chemistry*; D008856:Microscopy, Fluorescence; D009842:Oligopeptides / Q000737:chemistry*; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D013499:Surface Properties; D014466:Ultraviolet Rays
chemical_list: D009842:Oligopeptides; D003545:Cysteine
keywords: Cysteine label; Oligopeptide immobilization; UV