title: An intracellular antifreeze protein from an Antarctic microalga that responds to various environmental stresses.
abstract: The structure and function of the Antarctic marine diatom Chaetoceros neogracile antifreeze protein (Cn-AFP), as well as its expression levels and characteristics of the ice-binding site, were analyzed in the present study. In silico analysis revealed that the Cn-AFP promoter contains both light- and temperature-responsive elements. Northern and Western blot analyses demonstrated that both Cn-AFP transcript and protein expression were strongly and rapidly stimulated by freezing, as well as temperature and high light stress. Immunogold labeling revealed that Cn-AFP is preferentially localized to the intracellular space near the chloroplast membrane. Recombinant Cn-AFP had clear antifreeze activity. Protein-folding simulation was used to predict the putative ice-binding sites in Cn-AFP, and site-directed mutagenesis of the Cn-AFP b-face confirmed their identification.
authors.affiliation: Department of Life Science, Research Institute for Natural Sciences, Hanyang University, Seoul, Republic of Korea;
authors.forename: Yunho
authors.initials: Y
authors.lastname: Gwak
authors.affiliation: Department of Life Science, Research Institute for Natural Sciences, Hanyang University, Seoul, Republic of Korea; Division of Polar Life Science, Korea Polar Research Institute, Incheon, Republic of Korea; and.
authors.forename: Woongsic
authors.initials: W
authors.lastname: Jung
authors.affiliation: Department of Life Science, Research Institute for Natural Sciences, Hanyang University, Seoul, Republic of Korea;
authors.forename: Yew
authors.initials: Y
authors.lastname: Lee
authors.affiliation: Department of Life Science, Research Institute for Natural Sciences, Hanyang University, Seoul, Republic of Korea;
authors.forename: Ji Sook
authors.initials: JS
authors.lastname: Kim
authors.affiliation: Department of Life Science, Research Institute for Natural Sciences, Hanyang University, Seoul, Republic of Korea;
authors.forename: Chul Geun
authors.initials: CG
authors.lastname: Kim
authors.affiliation: Department of Life Science, Research Institute for Natural Sciences, Hanyang University, Seoul, Republic of Korea;
authors.forename: Ji-Hyun
authors.initials: JH
authors.lastname: Ju
authors.affiliation: Division of Electron Microscopic Research, Korea Basic Science Institute, Daejeon, Republic of Korea.
authors.forename: Chihong
authors.initials: C
authors.lastname: Song
authors.affiliation: Division of Electron Microscopic Research, Korea Basic Science Institute, Daejeon, Republic of Korea esjin@hanyang.ac.kr hjk022@kbsi.re.kr.
authors.forename: Jae-Kyung
authors.initials: JK
authors.lastname: Hyun
authors.affiliation: Department of Life Science, Research Institute for Natural Sciences, Hanyang University, Seoul, Republic of Korea; esjin@hanyang.ac.kr hjk022@kbsi.re.kr.
authors.forename: EonSeon
authors.initials: E
authors.lastname: Jin
mesh_terms: D021301:Antifreeze Proteins / Q000737:chemistry*; D001665:Binding Sites / Q000502:physiology; D003460:Crystallization; D007053:Ice; D058086:Microalgae / Q000737:chemistry*; D008958:Models, Molecular; D016297:Mutagenesis, Site-Directed; D017510:Protein Folding; D017433:Protein Structure, Secondary; D011994:Recombinant Proteins / Q000737:chemistry; D013312:Stress, Physiological
chemical_list: D021301:Antifreeze Proteins; D007053:Ice; D011994:Recombinant Proteins
keywords: Chaetoceros neogracile; ice-binding site; immunogold labeling