Crystal structure of the DNA-binding domain of BldD, a central regulator of aerial mycelium formation in Streptomyces coelicolor A3(2)

In Kwon Kim, Chang Jin Lee, Min Kyu Kim, Jeong Mok Kim, Ji Hye Kim, Hyung Soon Yim, Sun Shin Cha, Sa Ouk Kang

Research output: Contribution to journalArticlepeer-review

19 Scopus citations

Abstract

BldD is a central regulator of the developmental process in Streptomyces coelicolor. The 1.8 Å resolution structure of the DNA-binding domain of BldD (BldDN) reveals that BldDN forms a compact globular domain composed of four helices (α1-α4) containing a helix-turn-helix motif (α2-α3) resembling that of the DNA-binding domain of lambda repressor. The BldDN/DNA complex model led us to design a series of mutants, which revealed the important role of α3 and the 'turn' region between α2 and α3 for DNA recognition. Based on the fact that BldD occupies two operator sites of bldN and whiG and shows significant disparity in the affinity toward the two operator sites when they are disconnected, we propose a model of cooperative binding, which means that the binding of one BldD dimer to the high affinity site facilitates that of the second BldD dimer to the low affinity site. In addition, structural and mutational investigation reveals that the Tyr62Cys mutation, found in the first-identified bldD mutant, can destabilize BldD structure by disrupting the hydrophobic core.

Original languageEnglish
Pages (from-to)1179-1193
Number of pages15
JournalMolecular Microbiology
Volume60
Issue number5
DOIs
StatePublished - Jun 2006

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