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Anomalously Slow Conformational Change Dynamics of Polar Groups Anchored to Hydrophobic Surfaces in Aqueous Media
Author(s) -
Fu Tengfei,
Xing Hao,
Silver Eric S.,
Itoh Yoshimitsu,
Chen Shuo,
Masuda Takuya,
Uosaki Kohei,
Huang Feihe,
Aida Takuzo
Publication year - 2020
Publication title -
chemistry – an asian journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.18
H-Index - 106
eISSN - 1861-471X
pISSN - 1861-4728
DOI - 10.1002/asia.202000742
Subject(s) - polar , monolayer , chemistry , aqueous solution , chemical physics , conformational change , molecular dynamics , crystallography , molecule , side chain , self assembled monolayer , layer (electronics) , ionic bonding , hydrophobic effect , ion , stereochemistry , organic chemistry , computational chemistry , polymer , biochemistry , physics , astronomy
Water molecules within a thin hydration layer, spontaneously generated on hydrophobic protein surfaces, are reported to form a poorly dynamic network structure. However, how such a water network affects the conformational change dynamics of polar groups has never been explored, although such polar groups play a critical role in protein‐protein and protein‐ligand interactions. In the present work, we utilized as model protein surfaces a series of self‐assembled monolayers (SAMs) appended with polar (Fmoc) or ionic (FITC) fluorescent head groups that were tethered via a 1.5‐nm‐long flexible oligoether chain to a hydrophobic silicon wafer surface, which was densely covered with paraffinic chains. We found that, not only in deionized water but also in aqueous buffer, these oligoether‐appended head groups at ambient temperatures both displayed an anomalously slow conformational change, which required ∼10 h to reach a thermodynamically equilibrated state. We suppose that these behaviors reflect the poorly dynamic and low‐permittivity natures of the thin hydration layer.