PT  - JOURNAL ARTICLE
AU  - Guanzhong Ma
AU  - Hao Zhu
AU  - Zijian Wan
AU  - Yunze Yang
AU  - Shaopeng Wang
AU  - Nongjian Tao
TI  - Optical imaging of single protein size, charge, mobility, binding and conformational change
AID  - 10.1101/505404
DP  - 2019 Jan 01
TA  - bioRxiv
PG  - 505404
4099  - http://biorxiv.org/content/early/2019/03/03/505404.short
4100  - http://biorxiv.org/content/early/2019/03/03/505404.full
AB  - Protein analysis has relied on electrophoresis, mass spectroscopy and immunoassay, which separate, detect and identify proteins based on the size, charge, mobility and binding to antibodies. However, measuring these quantities at the single molecule level has not been possible. We tether a protein to a surface with a flexible polymer, drive the protein into mechanical oscillation with an alternating electric field, and image the protein oscillation with a near field imaging method, from which we determine the size, charge, mobility of the protein. We also measure binding of antibodies to single proteins and ligand binding-induced conformational changes in single proteins. This work provides new capabilities for protein analysis and disease biomarker detection at the single molecule level.