Structural analysis of Nickel uptake regulator (Nur) and Zinc uptake regulator (Zur) from Streptomyces coelicolor

Abstract

Various transition metal ions are essentially required for the cell growth and survival of almost all organisms. However, excess or lack of transition metal ions are very harmfulness. Thus, cells exploit highly sensitive metal ion-binding regulators to achieve homeostasis. In the present study, we describe the Crystal structure of (Nickel uptake regulator) Nur and (Zinc uptake regulator) Zur from Streptomyces coelicolor at 2.4-Å resolution. These two enzyme belongs to the ferric uptake regulator (Fur) family and controls expression of genes in response to available nickel or zinc. First, Nur is a nickel responsive transcription factor that controls nickel homeostasis and antioxidative response. It contains a unique nickel-specific metal site in addition to a nonspecific common metal site. The identification of the 6-5-6 motif of the Nur recognition box and a Nur/DNA complex model reveals that Nur mainly interacts with terminal bases of the palindrome on complex formation. This contrasts with more distributed contacts between Fur and the n-1-n type of the Fur-binding motif. seconds, Zur is zinc responsive transcription factor containing zinc-binding sites (C-,M- and D-sites). Mutations of the three sites differentially affected sporulation and transcription of target genes, such that C- and M-site mutations inhibited sporulation and derepressed all target genes examined, whereas D-site mng regulators to achieve homeostasis. In the present study, we describe the Crystal structure of (Nickel uptake regulator) Nur and (Zinc uptake regulator) Zur from Streptomyces coelicolor at 2.4-Å resolution. These two enzyme belongs to the ferric uptake regulator (Fur) family and controls expression of genes in response to available nickel or zinc. First, Nur is a nickel responsive transcription factor that controls nickel homeostasis and antioxidative response. It contains a unique nickel-specific metal site in addition to a nonspecific c