Structural basis for the specialization of Nur, a nickel-specific Fur homolog, in metal sensing and DNA recognition.
Nur, a member of the Fur family, is a nickel-responsive transcription factor that controls nickel homeostasis and anti-oxidative response in Streptomyces coelicolor. Here we report the 2.4-A resolution crystal structure of Nur. 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. The disparity between Nur and Fur in the conformation of the S1-S2 sheet in the DNA-binding domain can explain their different DNA-recognition patterns. Furthermore, the fact that the specificity of Nur in metal sensing and DNA recognition is conferred by the specific metal site suggests that its introduction drives the evolution of Nur orthologs in the Fur family.
An
Young Jun
YJ
Marine and Extreme Genome Research Center, Korea Ocean Research & Development Institute, Ansan 426-744, Republic of Korea.
Ahn
Bo-Eun
BE
Han
A-Reum
AR
Kim
Hae-Mi
HM
Chung
Kyung Min
KM
Shin
Jung-Ho
JH
Cho
Yoo-Bok
YB
Roe
Jung-Hye
JH
Cha
Sun-Shin
SS