title: Modulation of Biointeractions by Electrically Switchable Oligopeptide Surfaces: Structural Requirements and Mechanism.
abstract: Understanding the dynamic behavior of switchable surfaces is of paramount importance for the development of controllable and tailor-made surface materials. Herein, electrically switchable mixed self-assembled monolayers based on oligopeptides have been investigated in order to elucidate their conformational mechanism and structural requirements for the regulation of biomolecular interactions between proteins and ligands appended to the end of surface tethered oligopeptides. The interaction of the neutravidin protein to a surface appended biotin ligand was chosen as a model system. All the considerable experimental data, taken together with detailed computational work, support a switching mechanism in which biomolecular interactions are controlled by conformational changes between fullyextended("ON" state) andcollapsed("OFF" state) oligopeptide conformer structures. In the fullyextendedconformation, the biotin appended to the oligopeptide is largely free from steric factors allowing it to efficiently bind to the neutravidin from solution. While under acollapsedconformation, the ligand presented at the surface is partially embedded in the second component of the mixed SAM, and thus sterically shielded and inaccessible for neutravidin binding. Steric hindrances aroused from the neighboring surface-confined oligopeptide chains exert a great influence over the conformational behaviour of the oligopeptides, and as a consequence, over the switching efficiency. Our results also highlight the role of oligopeptide length in controlling binding switching efficiency. This study lays the foundation for designing and constructing dynamic surface materials with novel biological functions and capabilities, enabling their utilization in a wide variety of biological and medical applications.
authors: School of Chemical Engineering, University of Birmingham Edgbaston, Birmingham, B15 2TT, UK E-mail: p.m.mendes@bham.ac.uk.
authors: Chun L
authors: CL
authors: Yeung
authors: School of Chemistry, University of Birmingham Edgbaston, Birmingham, B15 2TT, UK.
authors: Xingyong
authors: X
authors: Wang
authors: School of Chemical Engineering, University of Birmingham Edgbaston, Birmingham, B15 2TT, UK E-mail: p.m.mendes@bham.ac.uk.
authors: Minhaj
authors: M
authors: Lashkor
authors: School of Chemical Engineering, University of Birmingham Edgbaston, Birmingham, B15 2TT, UK E-mail: p.m.mendes@bham.ac.uk.
authors: Eleonora
authors: E
authors: Cantini
authors: Laboratory of Biophysics and Surface Analysis, School of Pharmacy, University of Nottingham University Park, Nottingham, NG7 2RD, UK.
authors: Frankie J
authors: FJ
authors: Rawson
authors: School of Chemical Engineering, University of Birmingham Edgbaston, Birmingham, B15 2TT, UK E-mail: p.m.mendes@bham.ac.uk ; School of Chemistry, University of Birmingham Edgbaston, Birmingham, B15 2TT, UK.
authors: Parvez
authors: P
authors: Iqbal
authors: School of Chemistry, University of Birmingham Edgbaston, Birmingham, B15 2TT, UK.
authors: Jon A
authors: JA
authors: Preece
authors: School of Chemistry and Chemical Engineering, Nanjing University Nanjing, 210093, P. R. China E-mail: majing@nju.edu.cn.
authors: Jing
authors: J
authors: Ma
authors: School of Chemical Engineering, University of Birmingham Edgbaston, Birmingham, B15 2TT, UK E-mail: p.m.mendes@bham.ac.uk.
authors: Paula M
authors: PM
authors: Mendes
keywords: electrochemistry; molecular dynamic simulations; self-assembled monolayers; surface plasmon resonance; switchable surfaces