Crystallization of the bifunctional proteinase/amylase inhibitor PKI‐3 and of its complex with proteinase K

FEBS Letters

Betzel, Christian²  Pal, Gour P.²  Jany, Klaus-Dieter¹  Saenger, Wolfram² 

[1] Institut für Organische Chemie, Biochemie und Isotopenforschung der Universität Stuttgart, Pfaffenwaldring 55, D-7000 Stuttgart 80, FRG;Institut für Kristallographie, Freie Universität Berlin, Takustr. 6, D-1000 Berlin 33, Germany

关键词: Bifunctional inhibitor Amylase Enzyme inhibitor Proteinase K X-ray diffraction Crystallization;   

DOI  :  10.1016/0014-5793(86)80308-8

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

One of the three wheat germ inhibitors of proteinase K is bifunctional and inhibits simultaneously proteinase K (or subtilisin but not enzymes of the trypsin family) and insect α-amylase. The molecular mass of this inhibitor called PKI-3 is 21 kDa, and the binding constant for proteinase K is 0.8 nM at pH 8.2, 25°C, in 1:1 molar ratio. PKI-3 was crystallized by microdialysis against 10–12% polyethylene glycol 6000, 50 mM NaH₂PO₄, pH 6.7. The crystals have monoclinic space group P2₁ with a = 42.5, b = 65.3, c = 31.5 Å, β = 110°, and diffract beyond 2.0 Å resolution. The complex proteinase K · PKI-3 was crystallized by equilibrium vapor diffusion under the same conditions. The crystals are needle-shaped and still too small for X-ray analysis. Gel electrophoresis established the composition of the crystals.

【 授权许可】

Unknown