The refined 2.0 Å X‐ray crystal structure of the complex formed between bovine β‐trypsin and CMTI‐I, a trypsin inhibitor from squash seeds (Cucurbita maxima) Topological similarity of the squash seed inhibitors with the carboxypeptidase A inhibitor from potatoes

FEBS Letters

Huber, Robert²  Otlewski, Jacek¹  Greyling, H.Johann²  Bode, Wolfram²  Wilusz, Tadeusz¹ 

[1] Institute of Biochemistry, University of Wroclaw, Tamka 2, 50-137 Wroclaw, Poland;Max-Planck-Institut für Biochemie, D-8033 Martinsried, FRG

关键词: Serine proteinase inhibitor;    Trypsin;    Crystal structure;    Molecular complex;    Carboxypeptidase inhibitor;    CMTI;    Cucurbita maxima trypsin inhibitor;    CPI;    carboxypeptidase A inhibitor from potatoes;    rms;    root-mean-square;    B;    isotropic temperature factor;    Inhibitor residues are indicated by an I after the residue number;   

DOI  :  10.1016/0014-5793(89)80486-7

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

The stoichiometric complex formed between bovine β-trypsin and the Cucurbita maxima trypsin inhibitor I (CMTI-I) was crystallized and its X-ray crystal structure determined using Patterson search techniques. Its structure has been crystallographically refined to a final R value of 0.152 (6.0 — 2.0 Å). CMTI-I is of ellipsoidal shape; it lacks helices or β-sheets, but consists of turns and connecting short polypeptide stretches. The disulfide pairing is CYS-3I-20I, Cys-10I-22I and Cys-16I-28I. According to the polypeptide fold and disulfide connectivity its structure resembles that of the carboxypeptidase A inhibitor from potatoes. Thirteen of the 29 inhibitor residues are in direct contact with trypsin; most of them are in the primary binding segment Val-2I (P4) — Glu-9I (P4′) which contains the reactive site bond Arg-5I — Ile-6I and is in a conformation observed also for other serine proteinase inhibitors.

【 授权许可】

Unknown