title: Insights into the selective binding and toxic mechanism of microcystin to catalase.
abstract: Microcystin is a sort of cyclic nonribosomal peptides produced by cyanobacteria. It is cyanotoxin, which can be very toxic for plants and animals including humans. The present study evaluated the interaction of microcystin and catalase, under physiological conditions by means of fluorescence, three-dimensional (3D) fluorescence, circular dichroism (CD), Fourier Transform infrared (FT-IR) spectroscopy, and enzymatic reactionkinetic techniques. The fluorescence data showed that microcystin could bind to catalase to form a complex. The binding process was a spontaneous molecular interaction procedure, in which electrostatic interactions played a major role. Energy transfer and fluorescence studies proved the existence of a static binding process. Additionally, as shown by the three-dimensional fluorescence, CD and FT-IR results, microcystin could lead to conformational and microenvironmental changes of the protein, which may affect the physiological functions of catalase. The work provides important insights into the toxicity mechanism of microcystin in vivo.
authors.affiliation: Department of Environmental Science, East China Normal University, Shanghai 200062, China; Department of Landscape, Northeast Forestry University, Harbin 150040, China.
authors.forename: Yuandong
authors.initials: Y
authors.lastname: Hu
authors.affiliation: Department of Environmental Science, East China Normal University, Shanghai 200062, China. Electronic address: dalj@sh163.net.
authors.forename: Liangjun
authors.initials: L
authors.lastname: Da
mesh_terms: D002374:Catalase / Q000737:chemistry / Q000378:metabolism*; D002942:Circular Dichroism; D003841:Deoxycytidine / Q000031:analogs & derivatives / Q000494:pharmacology; D004735:Energy Transfer / Q000187:drug effects; D006863:Hydrogen-Ion Concentration; D052998:Microcystins / Q000737:chemistry / Q000378:metabolism* / Q000633:toxicity*; D011485:Protein Binding / Q000187:drug effects; D017433:Protein Structure, Secondary; D013050:Spectrometry, Fluorescence; D017550:Spectroscopy, Fourier Transform Infrared; D013696:Temperature; D000093542:Gemcitabine
chemical_list: D052998:Microcystins; D003841:Deoxycytidine; C078588:microcystin; D002374:Catalase; D000093542:Gemcitabine
keywords: Catalase; Cyanotoxin; Enzymatic inhabition; FT-IR; Fluorescence quenching