title: Molecular level studies on binding modes of labeling molecules with polyalanine peptides.
abstract: In this work, the binding modes of typical labeling molecules (thioflavin T (ThT), Congo red (CR) and copper(II) phthalocyanine tetrasulfonic acid tetrasodium salt (PcCu(SO(3)Na)(4))) on pentaalanine, which is a model peptide segment of amyloid peptides, have been resolved at the molecular level by using scanning tunneling microscopy (STM). In the STM images, ThT molecules are predominantly adsorbed parallel to the peptide strands and two binding modes could be identified. It was found that ThT molecules are preferentially binding on top of the peptide strand, and the mode of intercalated between neighboring peptides also exists. The parallel binding mode of CR molecules can be observed with pentaalanine peptides. Besides the binding modes of labeling molecules, the CR and PcCu(SO(3)Na)(4) display different adsorption affinity with the pentaalanine peptides. The results could be beneficial for obtaining molecular level insight of the interactions between labeling molecules and peptides.
authors.affiliation: National Center for Nanoscience and Technology, Beijing, 100190, China.
authors.forename: Xiaobo
authors.initials: X
authors.lastname: Mao
authors.forename: Chenxuan
authors.initials: C
authors.lastname: Wang
authors.forename: Xiaojing
authors.initials: X
authors.lastname: Ma
authors.forename: Min
authors.initials: M
authors.lastname: Zhang
authors.forename: Lei
authors.initials: L
authors.lastname: Liu
authors.forename: Lan
authors.initials: L
authors.lastname: Zhang
authors.forename: Lin
authors.initials: L
authors.lastname: Niu
authors.forename: Qindao
authors.initials: Q
authors.lastname: Zeng
authors.forename: Yanlian
authors.initials: Y
authors.lastname: Yang
authors.forename: Chen
authors.initials: C
authors.lastname: Wang
mesh_terms: D008422:Materials Testing / Q000379:methods; D016252:Microscopy, Scanning Tunneling / Q000379:methods*; D015336:Molecular Probe Techniques; D010455:Peptides / Q000737:chemistry*; D011485:Protein Binding; D013194:Staining and Labeling
chemical_list: D010455:Peptides; C019529:polyalanine