6RHF

Structure of Chloroflexus aggregans Cagg_3753 LOV domain C85A variant (CagFbFP)

Summary for 6RHF

• Entry DOI: 10.2210/pdb6rhf/pdb
• Descriptor: Multi-sensor hybrid histidine kinase, FLAVIN MONONUCLEOTIDE, GLYCEROL, ... (4 entities in total)
• Functional Keywords: lov, fmn, photoreceptor, fluorescent protein, flavoprotein
• Biological source: Chloroflexus aggregans (strain MD-66 / DSM 9485)
• Total number of polymer chains: 2
• Total formula weight: 25990.73

Authors

Nazarenko, V.V.,Remeeva, A.,Yudenko, A.,Kovalev, K.,Gordeliy, V.,Gushchin, I. (deposition date: 2019-04-19, release date: 2019-05-15, Last modification date: 2024-05-15)

Primary citation

Nazarenko, V.V.,Remeeva, A.,Yudenko, A.,Kovalev, K.,Dubenko, A.,Goncharov, I.M.,Kuzmichev, P.,Rogachev, A.V.,Buslaev, P.,Borshchevskiy, V.,Mishin, A.,Dhoke, G.V.,Schwaneberg, U.,Davari, M.D.,Jaeger, K.E.,Krauss, U.,Gordeliy, V.,Gushchin, I.
A thermostable flavin-based fluorescent protein from Chloroflexus aggregans: a framework for ultra-high resolution structural studies.
Photochem. Photobiol. Sci., 18:1793-1805, 2019

PubMed Abstract: Light-Oxygen-Voltage (LOV) domains are conserved parts of photoreceptors in plants, bacteria and fungi that bind flavins as chromophores and detect blue light. In the past, LOV domain variants have been developed as fluorescent reporter proteins (called flavin-based fluorescent proteins; FbFPs), which due to their ability to fluoresce under anaerobic conditions, fast folding kinetics and a small size of ∼12-16 kDa are a promising reporter system for quantitative real-time analysis of biological processes. Here, we present a small thermostable flavin-based fluorescent protein CagFbFP derived from a soluble LOV domain-containing histidine kinase from the thermophilic bacterium Chloroflexus aggregans. CagFbFP is composed of 107 amino acids with a molecular weight of 11.6 kDa and consists only of the conserved LOV core domain. The protein is thermostable with a melting point of about 68 °C. It crystallizes easily and its crystals diffract to 1.07 Å. Both the crystal structure and small angle scattering data show that the protein is a dimer. Unexpectedly, glutamine 148, which in LOV photoreceptor proteins is the key residue responsible for signal transduction, occupies two conformations. Molecular dynamics simulations show that the two conformations interconvert rapidly. The crystal structure of the wild-type Chloroflexus aggregans LOV domain determined at 1.22 Å resolution confirmed the presence of two alternative conformations of the glutamine 148 side chain. Overall, this protein, due to its stability and ease of crystallization, appears to be a promising model for ultra-high resolution structural studies of LOV domains and for application as a fluorescent reporter.

PubMed: 31116222
DOI: 10.1039/c9pp00067d

Experimental method

X-RAY DIFFRACTION (1.07 Å)