title: A simple and fast method to study the hydrodynamic size difference of protein disulfide isomerase in oxidized and reduced form using gold nanoparticles and dynamic light scattering.
abstract: The hydrodynamic dimension of a protein is a reflection of both its molecular weight and its tertiary structures. Studying the hydrodynamic dimensions of proteins in solutions can help elucidate the structural properties of proteins. Here we report a simple and fast method to measure the hydrodyamic size of a relatively small protein, protein disulfide isomerase (PDI), using gold nanoparticle probes combined with dynamic light scattering. Proteins can readily adsorb to citrate-capped gold nanoparticles to form a protein corona. By measuring the average diameter of the gold nanoparticles before and after protein corona formation, the hydrodynamic diameter of the protein can be deduced from the net particle size increase of the assay solution. This study found that when the disulfide bonds in PDI are reduced to thiols, the reduced PDI exhibits a smaller hydrodynamic diameter than the oxided PDI. This finding is in good agreement with the X-ray diffraction analysis of PDI in single crystals. In comparison with other techniques that are used for protein hydrodynamic size analysis, the current method is easy to use, requires a trace amount of protein samples, with results obtained in minutes instead of hours.
authors.affiliation: NanoScience Technology Center and Department of Chemistry, University of Central Florida, 12424 Research Parkway Suite 400, Orlando, FL 32826, USA. Qun.Huo@ucf.edu.
authors.forename: Tianyu
authors.initials: T
authors.lastname: Zheng
authors.forename: Patrick
authors.initials: P
authors.lastname: Cherubin
authors.forename: Lucia
authors.initials: L
authors.lastname: Cilenti
authors.forename: Ken
authors.initials: K
authors.lastname: Teter
authors.forename: Qun
authors.initials: Q
authors.lastname: Huo
mesh_terms: D000067493:Dynamic Light Scattering / Q000379:methods*; D006046:Gold / Q000737:chemistry*; D006801:Humans; D057446:Hydrodynamics; D053768:Metal Nanoparticles / Q000737:chemistry*; D010084:Oxidation-Reduction; D019704:Protein Disulfide-Isomerases / Q000737:chemistry / Q000378:metabolism*; D013997:Time Factors
chemical_list: D006046:Gold; D019704:Protein Disulfide-Isomerases