title: An ESIPT fluorescent probe sensitive to protein α-helix structures.
abstract: A large majority of membrane proteins have one or more transmembrane regions consisting of α-helices. Membrane protein levels differ from one type of cell to another, and the expression of membrane proteins also changes from normal to diseased cells. For example, prostate cancer cells have been reported to have downregulated expression of membrane proteins, including zinc transporters, compared with normal prostate cells. These reports inspired us to design a fluorescence probe sensitive to protein α-helical structures to discriminate individual prostate cancer cells from normal ones. A benzazole derivative ( in this study) was observed to emit strong fluorescence resulting from an excited-state intramolecular proton transfer (ESIPT) in protein α-helical environments. The intensity of ESIPT fluorescence of was observed to be positively correlated with the α-helix content of proteins. The molecular docking simulation suggested that it had low energy for the binding of to proteins when the binding sites were localized within the α-helical regions of protein via H-bonds. Furthermore, was found to be localized in cell membranes through binding to transmembrane α-helical regions of membrane proteins, and was capable of probing differences in the α-helix contents of membrane proteins between normal and cancerous prostate cells through changes in the ESIPT emission intensity. These results indicated that could distinguish individual prostate cancer cells from normal ones, as the changes in the ESIPT fluorescence intensity of could reflect the regulation in expression of the membrane proteins including zinc transporters. This recognition strategy of individual prostate cancer cells might contribute to early diagnosis techniques for prostate cancer.
authors.affiliation: Key Laboratory of Pesticide & Chemical Biology, Ministry of Education, School of Chemistry, Central China Normal University, Chemistry Building, Central China Normal University, Wuhan, China. liuchl@mail.ccnu.edu.cn danzhang@mail.ccnu.edu.cn.
authors.forename: Nan
authors.initials: N
authors.lastname: Jiang
authors.forename: Chanli
authors.initials: C
authors.lastname: Yang
authors.forename: Xiongwei
authors.initials: X
authors.lastname: Dong
authors.forename: Xianglang
authors.initials: X
authors.lastname: Sun
authors.forename: Dan
authors.initials: D
authors.lastname: Zhang
authors.forename: Changlin
authors.initials: C
authors.lastname: Liu
mesh_terms: D001583:Benzoxazoles / Q000138:chemical synthesis / Q000737:chemistry*; D001665:Binding Sites; D045744:Cell Line, Tumor; D002462:Cell Membrane / Q000737:chemistry / Q000473:pathology; D005456:Fluorescent Dyes / Q000138:chemical synthesis / Q000737:chemistry*; D006801:Humans; D008297:Male; D008565:Membrane Proteins / Q000032:analysis / Q000737:chemistry*; D062105:Molecular Docking Simulation; D009113:Muramidase / Q000032:analysis / Q000737:chemistry; D009928:Organ Specificity; D011467:Prostate / Q000737:chemistry / Q000473:pathology; D011485:Protein Binding; D017433:Protein Structure, Secondary; D011522:Protons; D012097:Repressor Proteins / Q000032:analysis / Q000737:chemistry*; D012709:Serum Albumin / Q000032:analysis / Q000737:chemistry; D059010:Single-Cell Analysis; D013050:Spectrometry, Fluorescence / Q000379:methods; D013816:Thermodynamics; D014357:Trypsin / Q000032:analysis / Q000737:chemistry
chemical_list: D001583:Benzoxazoles; D005456:Fluorescent Dyes; D008565:Membrane Proteins; D011522:Protons; D012097:Repressor Proteins; D012709:Serum Albumin; C549924:ZGPAT protein, human; D009113:Muramidase; D014357:Trypsin