PDBsum entry 2pr6

Flavoprotein, signaling protein

PDB id: 2pr6

Contents

Protein chains

128 a.a. *

Ligands

FMN ×2

Waters ×311

* Residue conservation analysis

PDB id:

2pr6

Name:

Flavoprotein, signaling protein

Title:

Structural basis for light-dependent signaling in the dimeric lov photosensor ytva (light structure)

Structure:

Blue-light photoreceptor. Chain: a, b. Fragment: residues 20-147. Engineered: yes

Source:

Bacillus subtilis. Organism_taxid: 1423. Gene: pfyp. Expressed in: escherichia coli bl21. Expression_system_taxid: 511693.

Resolution:

1.95Å R-factor: 0.184 R-free: 0.228

Authors:

A.Moglich,K.Moffat

Key ref:

A.Möglich and K.Moffat (2007). Structural Basis for Light-dependent Signaling in the Dimeric LOV Domain of the Photosensor YtvA. J Mol Biol, 373, 112-126. PubMed id: 17764689 DOI: 10.1016/j.jmb.2007.07.039

Date:

03-May-07 Release date: 07-Aug-07

Protein chains

O34627  (PHOT_BACSU) -  Blue-light photoreceptor from Bacillus subtilis (strain 168)

Seq: 261 a.a.

Struc: 128 a.a.

DOI no: 10.1016/j.jmb.2007.07.039

J Mol Biol 373:112-126 (2007)

PubMed id: 17764689

Structural Basis for Light-dependent Signaling in the Dimeric LOV Domain of the Photosensor YtvA.

A.Möglich, K.Moffat.

ABSTRACT

The photosensor YtvA binds flavin mononucleotide and regulates the general stress reaction in Bacillus subtilis in response to blue light illumination. It belongs to the family of light-oxygen-voltage (LOV) proteins that were first described in plant phototropins and form a subgroup of the Per-Arnt-Sim (PAS) superfamily. Here, we report the three-dimensional structure of the LOV domain of YtvA in its dark and light states. The protein assumes the global fold common to all PAS domains and dimerizes via a hydrophobic interface. Directly C-terminal to the core of the LOV domain, an alpha-helix extends into the solvent. Light absorption causes formation of a covalent bond between a conserved cysteine residue and atom C(4a) of the FMN ring, which triggers rearrangements throughout the LOV domain. Concomitantly, in the dark and light structures, the two subunits of the dimeric protein rotate relative to each other by 5 degrees . This small quaternary structural change is presumably a component of the mechanism by which the activity of YtvA is regulated in response to light. In terms of both structure and signaling mechanism, YtvA differs from plant phototropins and more closely resembles prokaryotic heme-binding PAS domains.

Selected figure(s)

Figure 2.
Figure 2. (a) Crystal structure of the head-to-head dimer of YtvA-LOV in its ground (dark) state. The FMN cofactors are highlighted in stick representation and the secondary structure elements (blue and light brown) are labeled. Within the crystal, the two C-terminal Jα helices form intermolecular contacts with the corresponding Jα' helices of symmetry-related molecules (white). For clarity, only the Jα helices of symmetry-related molecules are shown. (b) The dimer interface. Hydrophobic residues V25, V27, I29, Y41, M111, I113, Y118, V120, and I122 located on the outside of the β-sheet in strands Aβ, Bβ, Hβ and Iβ form intermolecular contacts between the two monomers.

Figure 3.
Figure 3. Comparison of the FMN-binding site in the dark state structures of (a) YtvA-LOV, (b) Chlamydomonas phot1 LOV1 and (c) Adiantum phy3 LOV2. Carbon atoms are shown in black, nitrogen atoms in blue, oxygen atoms in red, sulfur in yellow and phosphorus in magenta. Water molecules are depicted as red spheres. Broken green lines indicate hydrogen bonds or salt-bridges. The hydrogen bond network coordinating the FMN ring is highly conserved between the various LOV domains, whereas there is some variability in the hydrophobic residues lining the flavin ring. The key cysteine residue may adopt two conformations in the dark state, denoted a and b.

The above figures are reprinted from an Open Access publication published by Elsevier: J Mol Biol (2007, 373, 112-126) copyright 2007.

Figures were selected by an automated process.