PDBsum entry 2bgc

Transcription

PDB id: 2bgc

Contents

Protein chains

(+ 2 more) 235 a.a. *

Ligands

DTU

DTT

Waters ×389

* Residue conservation analysis

PDB id:

2bgc

Name:

Transcription

Title:

Prfa-g145s, a constitutive active mutant of the transcriptional regulator in l.Monocytogenes

Structure:

Prfa. Chain: a, b, d, e, f, g, h, i. Engineered: yes. Mutation: yes

Source:

Listeria monocytogenes. Organism_taxid: 169963. Strain: egd-e. Expressed in: escherichia coli. Expression_system_taxid: 562.

Biol. unit:

Dimer (from PDB file)

Resolution:

2.30Å R-factor: 0.199 R-free: 0.268

Authors:

M.Eiting,G.Hagelueken,W.-D.Schubert,D.W.Heinz

Key ref:

M.Eiting et al. (2005). The mutation G145S in PrfA, a key virulence regulator of Listeria monocytogenes, increases DNA-binding affinity by stabilizing the HTH motif. Mol Microbiol, 56, 433-446. PubMed id: 15813735

Date:

20-Dec-04 Release date: 14-Apr-05

Protein chains

P22262  (PRFA_LISMO) -  Listeriolysin regulatory protein from Listeria monocytogenes serovar 1/2a (strain ATCC BAA-679 / EGD-e)

Seq: 237 a.a.

Struc: 235 a.a.*

* PDB and UniProt seqs differ at 2 residue positions (black crosses)

Enzyme reactions

• Enzyme class: E.C.?

Mol Microbiol 56:433-446 (2005)

PubMed id: 15813735

The mutation G145S in PrfA, a key virulence regulator of Listeria monocytogenes, increases DNA-binding affinity by stabilizing the HTH motif.

M.Eiting, G.Hagelüken, W.D.Schubert, D.W.Heinz.

ABSTRACT

Listeria monocytogenes, a Gram-positive, facultative intracellular human pathogen, causes systemic infections with high mortality rate. The majority of the known pathogenicity factors of L. monocytogenes is regulated by a single transcription factor, PrfA. Hyperhaemolytic laboratory strains of L. monocytogenes express the constitutively active mutant PrfA(G145S) inducing virulence gene overexpression independent of environmental conditions. PrfA belongs to the Crp/Fnr family of transcription factors generally activated by a small effector, such as cAMP or O(2). We present the crystal structures of wild-type PrfA, the first Gram-positive member of the Crp/Fnr family, and of the constitutively active mutant PrfA(G145S). Cap (Crp) has previously been described exclusively in the cAMP-induced (DNA-free and -bound) conformation. By contrast, the PrfA structures present views both of the non-induced state and of the mutationally activated form. The low DNA-binding affinity of wild-type PrfA is supported both structurally (partly disordered helix-turn-helix motif, overall geometry of the HTH alpha-helices deviates from Cap) and by surface plasmon resonance analyses (K(D) = 0.9 microM). In PrfA(G145S) the HTH motifs dramatically rearrange to adopt a conformation comparable to cAMP-induced Cap and hence favourable for DNA binding, supported by a DNA-binding affinity of 50 nM. Finally, the hypothesis that wild-type PrfA, like other Crp/Fnr family members, may require an as yet unidentified cofactor for activation is supported by the presence of a distinct tunnel in PrfA, located at the interface of the beta-barrel and the DNA-binding domain.