DSSR-PyMOL cartoon-block schematics: PDB entry 6amk

PDB-id

6amk; DSSR-derived features in text and JSON formats

Class

DNA binding protein-DNA

Method

X-ray (3.288 Å)

Summary

Structure of streptomyces venezuelae bldc-whii opt complex

Reference

Schumacher MA, den Hengst CD, Bush MJ, Le TBK, Tran NT, Chandra G, Zeng W, Travis B, Brennan RG, Buttner MJ (2018): "The MerR-like protein BldC binds DNA direct repeats as cooperative multimers to regulate Streptomyces development." Nat Commun, 9, 1139. doi: 10.1038/s41467-018-03576-3.

Abstract

Streptomycetes are notable for their complex life cycle and production of most clinically important antibiotics. A key factor that controls entry into development and the onset of antibiotic production is the 68-residue protein, BldC. BldC is a putative DNA-binding protein related to MerR regulators, but lacks coiled-coil dimerization and effector-binding domains characteristic of classical MerR proteins. Hence, the molecular function of the protein has been unclear. Here we show that BldC is indeed a DNA-binding protein and controls a regulon that includes other key developmental regulators. Intriguingly, BldC DNA-binding sites vary significantly in length. Our BldC-DNA structures explain this DNA-binding capability by revealing that BldC utilizes a DNA-binding mode distinct from MerR and other known regulators, involving asymmetric head-to-tail oligomerization on DNA direct repeats that results in dramatic DNA distortion. Notably, BldC-like proteins radiate throughout eubacteria, establishing BldC as the founding member of a new structural family of regulators.