PDBsum entry 4zsb

Transcription

PDB id: 4zsb

Contents

Protein chain

162 a.a.

Waters ×75

PDB id:

4zsb

Name:

Transcription

Title:

Crystal structure of the ligand-free effector-binding domain of dasr (dasr-ebd)

Structure:

Hth-type transcriptional repressor dasr. Chain: a. Fragment: unp residues 89-254. Engineered: yes. Other_details: dasr-ebd comprises residues 88-254 of full-length dasr

Source:

Streptomyces coelicolor a3(2). Organism_taxid: 100226. Gene: dasr, sco5231, sc7e4.28c. Expressed in: escherichia coli. Expression_system_taxid: 562

Resolution:

2.00Å R-factor: 0.215 R-free: 0.256

Authors:

S.B.Fillenberg,F.C.Grau,Y.A.Muller

Key ref:

S.B.Fillenberg et al. (2016). Crystal Structures of the Global Regulator DasR from Streptomyces coelicolor: Implications for the Allosteric Regulation of GntR/HutC Repressors. Plos One, 11, e0157691. PubMed id: 27337024 DOI: 10.1371/journal.pone.0157691

Date:

13-May-15 Release date: 08-Jun-16

Protein chain

Q9K492  (DASR_STRCO) -  HTH-type transcriptional repressor DasR from Streptomyces coelicolor (strain ATCC BAA-471 / A3(2) / M145)

Seq: 254 a.a.

Struc: 162 a.a.

DOI no: 10.1371/journal.pone.0157691

Plos One 11:e0157691 (2016)

PubMed id: 27337024

Crystal Structures of the Global Regulator DasR from Streptomyces coelicolor: Implications for the Allosteric Regulation of GntR/HutC Repressors.

S.B.Fillenberg, M.D.Friess, S.Körner, R.A.Böckmann, Y.A.Muller.

ABSTRACT

Small molecule effectors regulate gene transcription in bacteria by altering the DNA-binding affinities of specific repressor proteins. Although the GntR proteins represent a large family of bacterial repressors, only little is known about the allosteric mechanism that enables their function. DasR from Streptomyces coelicolor belongs to the GntR/HutC subfamily and specifically recognises operators termed DasR-responsive elements (dre-sites). Its DNA-binding properties are modulated by phosphorylated sugars. Here, we present several crystal structures of DasR, namely of dimeric full-length DasR in the absence of any effector and of only the effector-binding domain (EBD) of DasR without effector or in complex with glucosamine-6-phosphate (GlcN-6-P) and N-acetylglucosamine-6-phosphate (GlcNAc-6-P). Together with molecular dynamics (MD) simulations and a comparison with other GntR/HutC family members these data allowed for a structural characterisation of the different functional states of DasR. Allostery in DasR and possibly in many other GntR/HutC family members is best described by a conformational selection model. In ligand-free DasR, an increased flexibility in the EBDs enables the attached DNA-binding domains (DBD) to sample a variety of different orientations and among these also a DNA-binding competent conformation. Effector binding to the EBDs of DasR significantly reorganises the atomic structure of the latter. However, rather than locking the orientation of the DBDs, the effector-induced formation of β-strand β* in the DBD-EBD-linker segment merely appears to take the DBDs 'on a shorter leash' thereby impeding the 'downwards' positioning of the DBDs that is necessary for a concerted binding of two DBDs of DasR to operator DNA.