TY - JOUR
AU - Brian O'Callahan
AU - Kevin Crampton
AU - Irina Novikova
AU - Tengyue Jian
AU - Chun-Long Chen
AU - James Evans
AU - Markus Raschke
AU - Patrick El-Khoury
AU - Scott Lea
AB - The mechanisms of interface biochemistry are often obscured through ensemble averaging of complex networks of proteins that exhibit varying degrees of structural heterogeneity. Here, we perform nanometer spatially resolved chemical spectroscopy using infrared vibrational scattering-scanning near-field optical microscopy (IR\ s-SNOM) to image protein\textendashprotein interactions and conformational heterogeneity of (i) a two-dimensional lipid-like peptoid membrane and (ii) a three-dimensional catalase crystal. In the peptoid membrane, which consists of stacked \~4 nm high peptoid layers, spatio-spectral line width analyses reveal heterogeneity of the vibrational dynamics due to peptoid\textendashsubstrate and peptoid\textendashpeptoid interactions. In\ s-SNOM imaging of catalase crystals, our results revealed complex secondary structures that vary over nanometer length scales. Broadening of vibrational resonances, as observed from the dehydrated catalase crystals, indicates a higher degree of heterogeneity as compared to the synthetic peptoid membranes. Our results thus demonstrate the utility of IR nanoscopy for the investigation of structural heterogeneity within biomimetic and\ biological systems with high spatio-spectral resolution and sensitivity.
BT - The Journal of Physical Chemistry C
DA - 2018-09
DO - 10.1021/acs.jpcc.8b06681
N2 - The mechanisms of interface biochemistry are often obscured through ensemble averaging of complex networks of proteins that exhibit varying degrees of structural heterogeneity. Here, we perform nanometer spatially resolved chemical spectroscopy using infrared vibrational scattering-scanning near-field optical microscopy (IR\ s-SNOM) to image protein\textendashprotein interactions and conformational heterogeneity of (i) a two-dimensional lipid-like peptoid membrane and (ii) a three-dimensional catalase crystal. In the peptoid membrane, which consists of stacked \~4 nm high peptoid layers, spatio-spectral line width analyses reveal heterogeneity of the vibrational dynamics due to peptoid\textendashsubstrate and peptoid\textendashpeptoid interactions. In\ s-SNOM imaging of catalase crystals, our results revealed complex secondary structures that vary over nanometer length scales. Broadening of vibrational resonances, as observed from the dehydrated catalase crystals, indicates a higher degree of heterogeneity as compared to the synthetic peptoid membranes. Our results thus demonstrate the utility of IR nanoscopy for the investigation of structural heterogeneity within biomimetic and\ biological systems with high spatio-spectral resolution and sensitivity.
PY - 2018
SP - 24891
EP - 24895
T2 - The Journal of Physical Chemistry C
TI - Imaging Nanoscale Heterogeneity in Ultrathin Biomimetic and Biological Crystals
UR - https://pubs.acs.org/doi/full/10.1021/acs.jpcc.8b06681
VL - 122
ER -