title: Mechanical Insight into Resistance of Betaine to Urea-Induced Protein Denaturation.
abstract: It is known that urea can induce protein denaturation that can be inhibited by osmolytes. Yet, experimental explorations on this mechanism at the molecular level are still lacking. We have investigated the resistance of betaine to the urea-induced denaturation of lysozyme in aqueous solutions using low-field NMR. Our study demonstrates that urea molecules directly interact with lysozyme, leading to denaturation. However, betaine molecules interacting with urea more strongly than lysozyme can pull the bound urea molecules from lysozyme so that the protein is protected from denaturation. The number of urea molecules bound to a betaine molecule is given under different conditions. Proton NMR spectroscopy (1H-NMR) and Fourier transform infrared spectroscopy reveal that the interaction between betaine and urea is through hydrogen bonding.
authors.affiliation: Faculty of Materials Science and Engineering, South China University of Technology , Guangzhou 510640, P. R. China.|College of Light Industry and Food Sciences, South China University of Technology , Guangzhou 510640, P. R. China.
authors.forename: Jiantao
authors.initials: J
authors.lastname: Chen
authors.affiliation: Faculty of Materials Science and Engineering, South China University of Technology , Guangzhou 510640, P. R. China.|College of Light Industry and Food Sciences, South China University of Technology , Guangzhou 510640, P. R. China.
authors.forename: Xiangjun
authors.initials: X
authors.lastname: Gong
authors.affiliation: Faculty of Materials Science and Engineering, South China University of Technology , Guangzhou 510640, P. R. China.|College of Light Industry and Food Sciences, South China University of Technology , Guangzhou 510640, P. R. China.
authors.forename: Chaoxi
authors.initials: C
authors.lastname: Zeng
authors.affiliation: Faculty of Materials Science and Engineering, South China University of Technology , Guangzhou 510640, P. R. China.|College of Light Industry and Food Sciences, South China University of Technology , Guangzhou 510640, P. R. China.
authors.forename: Yonghua
authors.initials: Y
authors.lastname: Wang
authors.affiliation: Faculty of Materials Science and Engineering, South China University of Technology , Guangzhou 510640, P. R. China.|College of Light Industry and Food Sciences, South China University of Technology , Guangzhou 510640, P. R. China.
authors.forename: Guangzhao
authors.initials: G
authors.lastname: Zhang
mesh_terms: D000818:Animals; D001622:Betaine / Q000737:chemistry*; D002645:Chickens; D004529:Egg White / Q000737:chemistry; D009113:Muramidase / Q000737:chemistry* / Q000378:metabolism; D011489:Protein Denaturation; D066244:Proton Magnetic Resonance Spectroscopy; D017550:Spectroscopy, Fourier Transform Infrared; D014508:Urea / Q000737:chemistry*
chemical_list: D001622:Betaine; D014508:Urea; D009113:Muramidase