The effect of graphene oxide on conformation change, aggregation and cytotoxicity of HIV-1 regulatory protein (Vpr)

Min Zhang, Xiaobo Mao, Chenxuan Wang, Wenfeng Zeng, Chunling Zhang, Zhongjun Li, Ying Fang, Yanlian Yang, Wei Liang, Chen Wang

Research output: Contribution to journalArticle

Abstract

The fragment of viral protein R (Vpr), Vpr13-33, plays an important role in regulating nuclear importing of HIV through ion channel formation with a leucine-zipper-like α-helical conformation. Herein we report an approach to reduce cytotoxicity of Vpr13-33 by graphene oxide induced conformation change and aggregation. Preferential adsorption of Vpr13-33 on graphene oxide accompanied by conformation change from α-helix to β-sheet structures has been observed by using atomic force microscopy (AFM) and circular dichroism (CD). The submolecular structures of the Vpr13-33 peptide assembly on graphite surface have been identified by using scanning tunneling microscopy (STM), which confirms the β-sheet structures of Vpr13-33 on graphene oxide surface. The reduced cytotoxicity of Vpr13-33 to neuroblastoma cells and T cells are detected by MTT assay, which could be associated with the conformation change and stimulated aggregation of Vpr13-33 upon addition of graphene oxide through hydrophobic interaction. Furthermore, fluorescent leakage assay by using large unilamellar vesicles (LUVs) indicated that the GO reduced Vpr13-33-induced cytotoxicity could be associated with the inhibited " pore forming" function of Vpr13-33 by conformation change and aggregation.

Original languageEnglish (US)
Pages (from-to)1383-1390
Number of pages8
JournalBiomaterials
Volume34
Issue number4
DOIs
StatePublished - Jan 1 2013

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Keywords

  • Aggregation
  • Conformation change
  • Cytotoxicity
  • Graphene oxide
  • Hydrophobic interaction
  • Vpr13-33

ASJC Scopus subject areas

  • Bioengineering
  • Ceramics and Composites
  • Biophysics
  • Biomaterials
  • Mechanics of Materials

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