红球菌属N-771的钴取代铁型腈水合酶

Cobalt-substituted Fe-type nitrile hydratase of Rhodococcus sp. N-771.

作者信息

Nojiri M, Nakayama H, Odaka M, Yohda M, Takio K, Endo I

机构信息

Biochemical Systems Laboratory, RIKEN (The Institute of Physical and Chemical Research), Hirosawa 2-1, Wako, Saitama, Japan.

出版信息

FEBS Lett. 2000 Jan 14;465(2-3):173-7. doi: 10.1016/s0014-5793(99)01746-9.

DOI:10.1016/s0014-5793(99)01746-9

PMID:10631329

Abstract

When the genes encoding alpha and beta subunits of Fe-type nitrile hydratase (NHase) from Rhodococcus sp. N-771 were expressed in Escherichia coli in Co-supplemented medium without co-expression of the NHase activator, the NHase specifically incorporated not Fe but Co ion into the catalytic center. The produced Co-substituted enzyme exhibited rather weak NHase activity, initially. However, the activity gradually increased by the incubation with an oxidizing agent, potassium hexacyanoferrate. The oxidizing agent is likely to activate the Co-substituent by oxidizing the Co atom to a low-spin Co(3+) state and/or modification of alphaCys-112 to a cysteine-sulfinic acid. It is suggested that the NHase activator not only supports the insertion of an Fe ion into the NHase protein but also activates the enzyme via the oxidation of its iron center.

摘要

当来自红球菌属N - 771的铁型腈水合酶（NHase）的α和β亚基编码基因在补充了钴的培养基中于大肠杆菌中表达，且未共表达NHase激活剂时，NHase特异性地将钴而非铁离子掺入催化中心。最初，所产生的钴取代酶表现出相当弱的NHase活性。然而，通过与氧化剂铁氰化钾孵育，其活性逐渐增加。该氧化剂可能通过将钴原子氧化为低自旋Co(3+)状态和/或将αCys - 112修饰为半胱氨酸亚磺酸来激活钴取代物。有人提出，NHase激活剂不仅支持将铁离子插入NHase蛋白中，还通过氧化其铁中心来激活该酶。