Oligomerization of an avian thymic parvalbumin Chemical evidence for a Ca2+‐specific conformation

FEBS Letters

Henzl, Michael T.¹  Hapak, Raymond C.¹  Zhao, Hongmei¹ 

[1] Biochemistry Department, 117 Schweitzer Hall, University of Missouri, Columbia, MO 65211, USA

关键词: Parvalbumin;    Ca2+-binding protein;    Disulfide bond;    ATH;    avian thymic hormone;    CPV3;    chicken parvalbumin isoform 3;    EGTA;    [ethylene-bis-(oxyethylenenitrilo)]tetraacetic acid;    DTT;    dithiothreitol;    DTNB;    5;    5′-dithio-bis-(2-nitrobenzoate);    HEPES;    4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid;    MES;    2-(N-morpholino)ethanesulfonic acid;    PAGE;    polyacrylamide gel electrophoresis;    PCR;    polymerase chain reaction;    CD site;    the metal ion-binding site in the parvalbumins flanked by the C and D helical segments;    EF site;    the metal ion-binding site in the parvalbumins flanked by the E and F helical segments;   

DOI  :  10.1016/0014-5793(94)00691-1

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

CPV3, the third parvalbumin isoform to be identified in the chicken, is produced exclusively in the thymus gland. Although parvalbumins are typically cysteine-deficient, CPV3 contains two cysteine residues, at positions 18 and 72. The reported three-dimensional parvalbumin structures suggest that the side chain of cysteine-72 should be solvent-accessible. Accordingly, we find that CPV3 readily forms disulfide-linked oligomers in the absence of reducing agents. The reaction, employing either O₂ or ferricyanide ion as the oxidant, is apparently restricted to the Ca²⁺-bound form of the protein. The differing reactivity of the Ca²⁺, Mg²⁺, and apo-forms has significant structural implications.

【 授权许可】

Unknown