The Copper Chaperone NosL Forms a Heterometal Site for Cu Delivery to Nitrous Oxide Reductase.

ABSTRACT: The final step of denitrification is the reduction of nitrous oxide (N₂ O) to N₂ , mediated by Cu-dependent nitrous oxide reductase (N₂ OR). Its metal centers, Cu_A and Cu_Z , are assembled through sequential provision of twelve Cu^I ions by a metallochaperone that forms part of a nos gene cluster encoding the enzyme and its accessory factors. The chaperone is the nosL gene product, an 18 kDa lipoprotein predicted to reside in the outer membrane of Gram-negative bacteria. In order to better understand the assembly of N₂ OR, we have produced NosL from Shewanella denitrificans and determined the structure of the metal-loaded chaperone by X-ray crystallography. The protein assembled a heterodinuclear metal site consisting of Zn^II and Cu^I , as evidenced by anomalous X-ray scattering. While only Cu^I is delivered to the enzyme, the stabilizing presence of Zn^II is essential for the functionality and structural integrity of the chaperone.

SUBMITTER: Prasser B 

PROVIDER: S-EPMC8457098 | biostudies-literature | 2021 Aug

REPOSITORIES: biostudies-literature