title: Effects of osmolytes on protein-solvent interactions in crowded environment: Analyzing the effect of TMAO on proteins in crowded solutions.
abstract: We analyzed the effect of a natural osmolyte, trimethylamine N-oxide (TMAO), on structural properties and conformational stabilities of several proteins under macromolecular crowding conditions by a set of biophysical techniques. We also used the solvent interaction analysis method to look at the peculiarities of the TMAO-protein interactions under crowded conditions. To this end, we analyzed the partitioning of these proteins in TMAO-free and TMAO-containing aqueous two-phase systems (ATPSs). These ATPSs had the same polymer composition of 6.0 wt.% PEG-8000 and 12.0 wt.% dextran-75, and same ionic composition of 0.01 M K/NaPB, pH 7.4. These analyses revealed that there is no direct interaction of TMAO with proteins, suggesting that the TMAO effects on the protein structure in crowded solutions occur via the effects of this osmolyte on solvent properties of aqueous media. The effects of TMAO on protein structure in the presence of polymers were rather complex and protein-specific. Curiously, our study revealed that in highly concentrated polymer solutions, TMAO does not always act to promote further protein folding.
authors.affiliation: Department of Molecular Medicine, University of South Florida, Tampa, FL 33612, USA; Byrd Alzheimer's Research Institute, Morsani College of Medicine, University of South Florida, Tampa, FL 33612, USA.
authors.forename: Leonid
authors.initials: L
authors.lastname: Breydo
authors.affiliation: Department of Molecular Medicine, University of South Florida, Tampa, FL 33612, USA; Department of Morphology and Animal Physiology, Federal Rural University of Pernambuco, 52171-900 Recife, PE, Brazil.
authors.forename: Amanda E
authors.initials: AE
authors.lastname: Sales
authors.affiliation: Analiza, Inc., 3516 Superior Ave., Suite 4407B, Cleveland, USA.
authors.forename: Luisa
authors.initials: L
authors.lastname: Ferreira
authors.affiliation: Analiza, Inc., 3516 Superior Ave., Suite 4407B, Cleveland, USA.
authors.forename: Olga
authors.initials: O
authors.lastname: Fedotoff
authors.affiliation: Institute for Biological Instrumentation, Russian Academy of Sciences, Pushchino, Moscow Region 142290, Russia.
authors.forename: Marina P
authors.initials: MP
authors.lastname: Shevelyova
authors.affiliation: Institute for Biological Instrumentation, Russian Academy of Sciences, Pushchino, Moscow Region 142290, Russia.
authors.forename: Sergei E
authors.initials: SE
authors.lastname: Permyakov
authors.affiliation: Department of Molecular Medicine, University of South Florida, Tampa, FL 33612, USA.
authors.forename: Kyle G
authors.initials: KG
authors.lastname: Kroeck
authors.affiliation: Institute for Biological Instrumentation, Russian Academy of Sciences, Pushchino, Moscow Region 142290, Russia.
authors.forename: Eugene A
authors.initials: EA
authors.lastname: Permyakov
authors.affiliation: Analiza, Inc., 3516 Superior Ave., Suite 4407B, Cleveland, USA.
authors.forename: Boris Y
authors.initials: BY
authors.lastname: Zaslavsky
authors.affiliation: Department of Molecular Medicine, University of South Florida, Tampa, FL 33612, USA; Byrd Alzheimer's Research Institute, Morsani College of Medicine, University of South Florida, Tampa, FL 33612, USA; Institute for Biological Instrumentation, Russian Academy of Sciences, Pushchino, Moscow Region 142290, Russia; Department of Biological Science, Faculty of Science, King Abdulaziz University, PO Box 80203, Jeddah 21589, Saudi Arabia; Laboratory of Structural Dynamics, Stability and Folding of Proteins, Institute of Cytology, Russian Academy of Sciences, St. Petersburg, Russia. Electronic address: vuversky@health.usf.edu.
authors.forename: Vladimir N
authors.initials: VN
authors.lastname: Uversky
mesh_terms: D000818:Animals; D002152:Calorimetry, Differential Scanning; D002417:Cattle; D002918:Chymotrypsin / Q000737:chemistry; D002942:Circular Dichroism; D003911:Dextrans / Q000737:chemistry; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008027:Light; D008744:Methylamines / Q000737:chemistry*; D010179:Pancreas / Q000378:metabolism; D011092:Polyethylene Glycols / Q000737:chemistry; D011108:Polymers / Q000737:chemistry; D011485:Protein Binding; D017510:Protein Folding; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D012542:Scattering, Radiation; D012997:Solvents / Q000737:chemistry; D013050:Spectrometry, Fluorescence; D013696:Temperature; D014867:Water / Q000737:chemistry
chemical_list: D003911:Dextrans; D008744:Methylamines; D011108:Polymers; D012997:Solvents; D014867:Water; D011092:Polyethylene Glycols; D002918:Chymotrypsin; C117608:alpha-chymotrypsin; C005855:trimethyloxamine
keywords: Aqueous two-phase system; Macromolecular crowding; Partitioning; Protein stability; Protein structure; Solvent interaction analysis; Structural changes