Inhibitory serpins from rye grain with glutamine as P1 and P2 residues in the reactive center

FEBS Letters

Hejgaard, Jørn¹ 

[1] Department of Biochemistry and Nutrition, Technical University of Denmark, Bldg 224, DK-2800 Lyngby, Denmark

关键词: Chymotrypsin inhibitor;    Prolamin;    Serpin;    Secale cereale;    BSZ;    RSZ and WSZ;    barley;    rye and wheat serpins (protein Z family);    DTT;    dithiothreitol;    PAGE;    polyacrylamide gel electrophoresis;    PVDF;    polyvinylidene difluoride;    RCL;    reactive center loop;    SDS;    sodium dodecyl sulfate;   

DOI  :  10.1016/S0014-5793(00)02425-X

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Six of seven serpins detected in grains of rye (Secale cereale) were purified and characterized. The amino acid sequence close to the blocked N-terminus, the reactive center loop sequence and the second order association rate constant (k _a′) for irreversible complex formation with chymotrypsin were determined for each serpin. Three of four serpins containing the unusual reactive center P₂–P₁′ QQ↓S and one with P₂–P₁′ PQ↓M were equally efficient inhibitors of chymotrypsin (k _a′∼10⁵ M⁻¹ s⁻¹). One serpin with P₂–P₁′ PY↓M was a faster inhibitor (k _a′∼10⁶ M⁻¹ s⁻¹). Similar but differently organized glutamine-rich reactive centers were recently found in grain serpins cloned from wheat [Østergaard et al. (2000) J. Biol. Chem. 275, 33272] but not from barley. The prolamin storage proteins of cereal grains contain similar sequences in their glutamine-rich repeats. A possible adaption of hypervariable serpin reactive centers late in Triticeae cereal evolution as defence against insects feeding on cereal grains is discussed.

【 授权许可】

Unknown