Summary information and primary citation
- PDB-id
-
7x74;
DSSR-derived features in text and
JSON formats
- Class
- DNA binding protein
- Method
- cryo-EM (3.7 Å)
- Summary
- cryo-EM structure of streptomyces coelicolor
transcription initial complex with two zur dimers.
- Reference
-
Yang X, Wang Y, Liu G, Deng Z, Lin S, Zheng J (2022):
"Structural
basis of Streptomyces transcription activation by zinc
uptake regulator." Nucleic Acids Res.,
50, 8363-8376. doi: 10.1093/nar/gkac627.
- Abstract
- Streptomyces coelicolor (Sc) is a model organism of
actinobacteria to study morphological differentiation and
production of bioactive metabolites. Sc zinc uptake
regulator (Zur) affects both processes by controlling zinc
homeostasis. It activates transcription by binding to
palindromic Zur-box sequences upstream of -35 elements.
Here we deciphered the molecular mechanism by which ScZur
interacts with promoter DNA and Sc RNA polymerase (RNAP) by
cryo-EM structures and biochemical assays. The ScZur-DNA
structures reveal a sequential and cooperative binding of
three ScZur dimers surrounding a Zur-box spaced 8 nt
upstream from a -35 element. The ScRNAPσHrdB-Zur-DNA
structures define protein-protein and protein-DNA
interactions involved in the principal housekeeping
σHrdB-dependent transcription initiation from a
noncanonical promoter with a -10 element lacking the
critical adenine residue at position -11 and a TTGCCC -35
element deviating from the canonical TTGACA motif. ScZur
interacts with the C-terminal domain of ScRNAP α subunit
(αCTD) in a complex structure trapped in an active
conformation. Key ScZur-αCTD interfacial residues
accounting for ScZur-dependent transcription activation
were confirmed by mutational studies. Together, our
structural and biochemical results provide a comprehensive
model for transcription activation of Zur family
regulators.
