Purification, crystal structure determination and functional characterization 1 of type III antifreeze proteins from the fish Zoarces viviparus

Jens-Christian N. Poulsen, Hans Ramløv, Leila Lo Leggio, Casper Wilkens

    Publikation: Bidrag til tidsskriftTidsskriftartikelForskningpeer review

    Abstract

    Antifreeze proteins (AFPs) are essential components of many organisms adaptation to cold temperatures. Fish type III AFPs are divided into two groups, SP isoforms being much less active than QAE1 isoforms. Two type III AFPs from Zoarces viviparus, a QAE1 (ZvAFP13) and an SP (ZvAFP6) isoform, are here characterized and their crystal structures determined. We conclude that the higher activity of the QAE1 isoforms cannot be attributed to single residues, but rather a combination of structural effects. Furthermore both ZvAFP6 and ZvAFP13 crystal structures have water molecules around T18 equivalent to the tetrahedral-like waters previously identified in a neutron crystal structure. Interestingly, ZvAFP6 forms dimers in the crystal, with a significant dimer interface. The presence of ZvAFP6 dimers was confirmed in solution by native electrophoresis and gel filtration. To our knowledge this is the first report of dimerization of AFP type III proteins.
    OriginalsprogEngelsk
    TidsskriftCryobiology
    Vol/bind69
    Sider (fra-til)163-168
    Antal sider6
    ISSN0011-2240
    DOI
    StatusUdgivet - 12 jul. 2014

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