title: Structure and activity of lysozyme on binding to ZnO nanoparticles.
abstract: The interaction between ZnO nanoparticles (NPs) and lysozyme has been studied using calorimetric as well as spectrophotometric techniques, and interpreted in terms of the three-dimensional structure. The circular dichroism spectroscopic data show an increase in alpha-helical content on interaction with ZnO NPs. Glutaraldehyde cross-linking studies indicate that the monomeric form occurs to a greater extent than the dimer when lysozyme is conjugated with ZnO NPs. The enthalpy-driven binding between lysozyme and ZnO possibly involves the region encompassing the active site in the molecule, which is also the site for the dimer formation in a homologous structure. The enzyme retains high fraction of its native structure with negligible effect on its activity upon attachment to NPs. Compared to the free protein, lysozyme-ZnO conjugates are more stable in the presence of chaotropic agents (guanidine hydrochloride and urea) and also at elevated temperatures. The possible site of binding of NP to lysozyme has been proposed to explain these observations. The stability and the retention of a higher level of activity in the presence of the denaturing agent of the NP-conjugated protein may find useful applications in biotechnology ranging from diagnostic to drug delivery.
authors.affiliation: Department of Biochemistry, Bose Institute, P-1/12 CIT Scheme VIIM, Kolkata 700054, India.
authors.forename: Soumyananda
authors.initials: S
authors.lastname: Chakraborti
authors.forename: Tanaya
authors.initials: T
authors.lastname: Chatterjee
authors.forename: Prachi
authors.initials: P
authors.lastname: Joshi
authors.forename: Asim
authors.initials: A
authors.lastname: Poddar
authors.forename: Bhabatarak
authors.initials: B
authors.lastname: Bhattacharyya
authors.forename: Surinder P
authors.initials: SP
authors.lastname: Singh
authors.forename: Vinay
authors.initials: V
authors.lastname: Gupta
authors.forename: Pinak
authors.initials: P
authors.lastname: Chakrabarti
mesh_terms: D000817:Anilino Naphthalenesulfonates / Q000378:metabolism; D000818:Animals; D002151:Calorimetry; D020134:Catalytic Domain; D003432:Cross-Linking Reagents / Q000494:pharmacology; D005976:Glutaral / Q000494:pharmacology; D019791:Guanidine / Q000494:pharmacology; D006863:Hydrogen-Ion Concentration; D008958:Models, Molecular; D009113:Muramidase / Q000737:chemistry* / Q000378:metabolism*; D053758:Nanoparticles / Q000737:chemistry*; D010316:Particle Size; D011489:Protein Denaturation / Q000187:drug effects; D055503:Protein Multimerization / Q000187:drug effects; D020836:Protein Structure, Quaternary / Q000187:drug effects; D017433:Protein Structure, Secondary / Q000187:drug effects; D013050:Spectrometry, Fluorescence; D013816:Thermodynamics; D014508:Urea / Q000494:pharmacology; D015034:Zinc Oxide / Q000737:chemistry* / Q000378:metabolism* / Q000494:pharmacology
chemical_list: C515594:8-anilino-1-naphthalenesulfonic acid; D000817:Anilino Naphthalenesulfonates; D003432:Cross-Linking Reagents; D014508:Urea; D009113:Muramidase; D019791:Guanidine; D015034:Zinc Oxide; D005976:Glutaral