title: NMR study of the antifreeze activities of active and inactive isoforms of a type III antifreeze protein.
abstract: The quaternary-amino-ethyl 1 (QAE1) isoforms of type III antifreeze proteins (AFPs) prevent the growth of ice crystals within organisms living in polar regions. We determined the antifreeze activity of wild-type and mutant constructs of the Japanese notched-fin eelpout (Zoarces elongates Kner) AFP8 (nfeAFP8) and characterized the structural and dynamics properties of their ice-binding surface using NMR. We found that the three constructs containing the V20G mutation were incapable of stopping the growth of ice crystals and exhibited structural changes, as well as increased conformational flexibility, in the first 310helix (residues 18-22) of the sequence. Our results suggest that the inactive nfeAFP8s are incapable of anchoring water molecules due to the unusual and flexible backbone conformation of their primary prism plane-binding surface.
authors.affiliation: Department of Chemistry and RINS, Gyeongsang National University, Gyeongnam, Korea.
authors.forename: Seo-Ree
authors.initials: SR
authors.lastname: Choi
authors.affiliation: Department of Chemistry and RINS, Gyeongsang National University, Gyeongnam, Korea.
authors.forename: Yeo-Jin
authors.initials: YJ
authors.lastname: Seo
authors.affiliation: Department of Life Science, Hanyang University, Seoul, Korea.
authors.forename: Minjae
authors.initials: M
authors.lastname: Kim
authors.affiliation: College of Pharmacy, Dongguk University, Gyeonggi, Korea.
authors.forename: Yumi
authors.initials: Y
authors.lastname: Eo
authors.affiliation: College of Pharmacy, Dongguk University, Gyeonggi, Korea.
authors.forename: Hee-Chul
authors.initials: HC
authors.lastname: Ahn
authors.affiliation: Department of Chemistry and RINS, Gyeongsang National University, Gyeongnam, Korea.
authors.forename: Ae-Ree
authors.initials: AR
authors.lastname: Lee
authors.affiliation: Department of Chemistry, GIST, Gwangju, Korea.
authors.forename: Chin-Ju
authors.initials: CJ
authors.lastname: Park
authors.affiliation: Division of Magnetic Resonance, KBSI, Chungbuk, Korea.
authors.forename: Kyoung-Seok
authors.initials: KS
authors.lastname: Ryu
authors.affiliation: Division of Magnetic Resonance, KBSI, Chungbuk, Korea.
authors.forename: Hae-Kap
authors.initials: HK
authors.lastname: Cheong
authors.affiliation: Department of Chemistry and RINS, Gyeongsang National University, Gyeongnam, Korea.
authors.forename: Shim Sung
authors.initials: SS
authors.lastname: Lee
authors.affiliation: Department of Life Science, Hanyang University, Seoul, Korea.
authors.forename: EonSeon
authors.initials: E
authors.lastname: Jin
authors.affiliation: Department of Chemistry and RINS, Gyeongsang National University, Gyeongnam, Korea.|Division of Magnetic Resonance, KBSI, Chungbuk, Korea.
authors.forename: Joon-Hwa
authors.initials: JH
authors.lastname: Lee
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D021343:Antifreeze Proteins, Type III / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D029941:Fish Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D009154:Mutation; D010473:Perciformes; D020033:Protein Isoforms / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D017433:Protein Structure, Secondary; D013696:Temperature
chemical_list: D021343:Antifreeze Proteins, Type III; D029941:Fish Proteins; D020033:Protein Isoforms
keywords: 
  NMR
  ; antifreeze protein; ice-binding protein; protein dynamics