The ternary complex of DNase I, actin and thymosin β4

FEBS Letters

Voelter, Wolfgang¹  Faulstich, Heinz²  Heintz, Daniela²  Reichert, Andreas²  Echner, Hartmut¹ 

[1] Abteilung für Physikalische Biochemie des Physiologisch-chemischen Instituts der Universität Tübingen, Tübingen, Germany;Max-Planck-Institut für medizinische Forschung, Heidelberg, Germany

关键词: Actin;    Thymosin β4;    DNase I;    Ternary complex;    Thiol-specific crosslinking;    Tβ4;    thymosin β4;    ADF;    actin-depolymerizing factor;    ArSS-(CH2)3-SSAr;    propylene-bis-[5-dithio-(2-nitrobenzoic acid)];    ArS−;    2-nitro-5-thiobenzoate;    TLC;    thin-layer chromatography;    DTT;    dithiothreitol;    TMB;    trimethylammonio-bromobimane;    PMSF;    phenylmethylsulfonyl fluoride;   

DOI  :  10.1016/0014-5793(96)00488-7

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

We have recently described a method for identifying contact sites between actin and thymosin β4 (Tβ4) by following spectrophotometrically the extent and kinetics of distinct, thiolspecific crosslinking reactions between appropriate derivatives of the two proteins [Reichert et al. (1996) J. Biol. Chem. 271, 1301–1308]. In the present study this method was used to show that such crosslinking, which is indicative of complex formation, occurs to the same extent with the actin-DNase I complex as with pure actin, although at a somewhat lower rate. Further evidence for the formation of the ternary complex was given by gel electrophoresis. From fluorescence spectroscopy the K _D value of Tβ4 from the actin-DNase I complex was found to be identical to that from pure actin. In line with these data, the capacity of actin for inhibiting DNase I was not affected by the addition of Tβ4. In conclusion, DNase I and Tβ4 are independent of each other in their interaction with actin, suggesting that the binding sites of thymosin β4 and DNase I on actin do not overlap. A ternary complex of DNase I, actin and Tβ4, if obtained in crystalline form, could thus provide an approach for studying the interface of Tβ4 and actin by X-ray analysis.

【 授权许可】

Unknown