PDBsum entry 6bap

Signaling protein

PDB id: 6bap

Contents

Protein chains

505 a.a.

Ligands

BLR ×3

Waters ×124

PDB id:

6bap

Name:

Signaling protein

Title:

Stigmatella aurantiaca bacterial phytochrome pas-gaf-phy, t289h mutant

Structure:

Photoreceptor-histidine kinase bphp. Chain: a, b, c. Fragment: pas-gaf-phy (unp residues 1-515). Synonym: sensor protein. Engineered: yes. Mutation: yes

Source:

Stigmatella aurantiaca dw4/3-1. Organism_taxid: 378806. Strain: dw4/3-1. Gene: staur_8015, stiau_3396. Expressed in: escherichia coli. Expression_system_taxid: 562

Resolution:

2.65Å R-factor: 0.245 R-free: 0.315

Authors:

M.Schmidt,E.Stojkovic

Key ref:

N.C.Woitowich et al. (2018). Structural basis for light control of cell development revealed by crystal structures of a myxobacterial phytochrome. IUCrJ, 5, 619-634. PubMed id: 30224965

Date:

14-Oct-17 Release date: 19-Sep-18

Protein chains

Q097N3  (Q097N3_STIAD) -  histidine kinase from Stigmatella aurantiaca (strain DW4/3-1)

Seq: 760 a.a.

Struc: 505 a.a.*

* PDB and UniProt seqs differ at 1 residue position (black cross)

Enzyme reactions

• Enzyme class: E.C.2.7.13.3 - histidine kinase.
• Reaction: ATP + protein L-histidine = ADP + protein N-phospho-L-histidine

Molecule diagrams generated from .mol files obtained from the KEGG ftp site

reference

IUCrJ 5:619-634 (2018)

PubMed id: 30224965

Structural basis for light control of cell development revealed by crystal structures of a myxobacterial phytochrome.

N.C.Woitowich, A.S.Halavaty, P.Waltz, C.Kupitz, J.Valera, G.Tracy, K.D.Gallagher, E.Claesson, T.Nakane, S.Pandey, G.Nelson, R.Tanaka, E.Nango, E.Mizohata, S.Owada, K.Tono, Y.Joti, A.C.Nugent, H.Patel, A.Mapara, J.Hopkins, P.Duong, D.Bizhga, S.E.Kovaleva, R.St Peter, C.N.Hernandez, W.B.Ozarowski, S.Roy-Chowdhuri, J.H.Yang, P.Edlund, H.Takala, J.Ihalainen, J.Brayshaw, T.Norwood, I.Poudyal, P.Fromme, J.C.H.Spence, K.Moffat, S.Westenhoff, M.Schmidt, E.A.Stojković.

ABSTRACT

Phytochromes are red-light photoreceptors that were first characterized in plants, with homologs in photosynthetic and non-photosynthetic bacteria known as bacteriophytochromes (BphPs). Upon absorption of light, BphPs interconvert between two states denoted Pr and Pfr with distinct absorption spectra in the red and far-red. They have recently been engineered as enzymatic photoswitches for fluorescent-marker applications in non-invasive tissue imaging of mammals. This article presents cryo- and room-temperature crystal structures of the unusual phytochrome from the non-photosynthetic myxo-bacterium Stigmatella aurantiaca (SaBphP1) and reveals its role in the fruiting-body formation of this photomorphogenic bacterium. SaBphP1 lacks a conserved histidine (His) in the chromophore-binding domain that stabilizes the Pr state in the classical BphPs. Instead it contains a threonine (Thr), a feature that is restricted to several myxobacterial phytochromes and is not evolutionarily understood. SaBphP1 structures of the chromophore binding domain (CBD) and the complete photosensory core module (PCM) in wild-type and Thr-to-His mutant forms reveal details of the molecular mechanism of the Pr/Pfr transition associated with the physiological response of this myxobacterium to red light. Specifically, key structural differences in the CBD and PCM between the wild-type and the Thr-to-His mutant involve essential chromophore contacts with proximal amino acids, and point to how the photosignal is transduced through the rest of the protein, impacting the essential enzymatic activity in the photomorphogenic response of this myxobacterium.