Herrera-Mendez Carlos H, Becila Samira, Blanchet Xavier, Pelissier Patrick, Delourme Didier, Coulis Gerald, Sentandreu Miguel A, Boudjellal Abdelghani, Bremaud Laure, Ouali Ahmed
UNESS, Universidad de Guanajuato, Privada de Arteaga S/N, 38900 Salvatierra, Guanajuato, Mexico.
FEBS Lett. 2009 Sep 3;583(17):2743-8. doi: 10.1016/j.febslet.2009.07.055. Epub 2009 Aug 7.
Serpins are a superfamily of structurally conserved proteins. Inhibitory serpins use a suicide substrate-like mechanism. Some are able to inhibit cysteine proteases in cross-class inhibition. Here, we demonstrate for the first time the strong inhibition of initiator and effector caspases 3 and 8 by two purified bovine SERPINA3s. SERPINA 3-1 (uniprotkb:Q9TTE1) binds tighly to human CASP3 (uniprotkb:P42574) and CASP8 (uniprotkb:Q14790) with k(ass) of 4.2x10(5) and 1.4x10(6) M(-1)s(-1), respectively. A wholly similar inhibition of human CASP3 and CASP8 by SERPINA3-3 (uniprotkb:Q3ZEJ6) was also observed with k(ass) of 1.5x10(5) and 2.7x10(6) M(-1)s(-1), respectively and form SDS-stable complexes with both caspases. By site-directed mutagenesis of bovSERPINA3-3, we identified Asp(371) as the potential P1 residue for caspases. The ability of other members of this family to inhibit trypsin and caspases was analysed and discussed.
丝氨酸蛋白酶抑制剂是一类结构保守的蛋白质超家族。抑制性丝氨酸蛋白酶抑制剂采用类似自杀底物的机制。有些能够在跨类抑制中抑制半胱氨酸蛋白酶。在此，我们首次证明两种纯化的牛SERPINA3对起始和效应半胱天冬酶3和8具有强烈抑制作用。SERPINA 3-1（uniprotkb:Q9TTE1）与人类CASP3（uniprotkb:P42574）和CASP8（uniprotkb:Q14790）紧密结合，结合常数（k(ass)）分别为4.2x10(5)和1.4x10(6) M(-1)s(-1)。还观察到SERPINA3-3（uniprotkb:Q3ZEJ6）对人类CASP3和CASP8有完全相似的抑制作用。其结合常数分别为1.5x10(5)和2.7x10(6) M(-1)s(-1)，并与两种半胱天冬酶形成SDS稳定复合物。通过对牛SERPINA3-3进行定点诱变，我们确定天冬氨酸（Asp(371)）为半胱天冬酶的潜在P1残基。分析并讨论了该家族其他成员抑制胰蛋白酶和半胱天冬酶 的能力。
