PDBsum entry 4n1f

Luminescent protein

PDB id: 4n1f

Contents

Protein chain

186 a.a.

Ligands

CZH

Waters ×164

PDB id:

4n1f

Name:

Luminescent protein

Title:

Crystal structure of f88y obelin mutant from obelia longissima at 2.09 angstrom resolution

Structure:

Obelin. Chain: a. Synonym: obl. Engineered: yes. Mutation: yes

Source:

Obelia longissima. Black sea hydrozoan. Organism_taxid: 32570. Expressed in: escherichia coli. Expression_system_taxid: 562.

Resolution:

2.09Å R-factor: 0.174 R-free: 0.199

Authors:

P.V.Natashin,S.V.Markova,J.Lee,E.S.Vysotski,Z.J.Liu

Key ref:

P.V.Natashin et al. (2014). Crystal structures of the F88Y obelin mutant before and after bioluminescence provide molecular insight into spectral tuning among hydromedusan photoproteins. Febs J, 281, 1432-1445. PubMed id: 24418253 DOI: 10.1111/febs.12715

Date:

04-Oct-13 Release date: 19-Feb-14

Protein chain

Q27709  (OBL_OBELO) -  Obelin from Obelia longissima

Seq: 195 a.a.

Struc: 186 a.a.*

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

DOI no: 10.1111/febs.12715

Febs J 281:1432-1445 (2014)

PubMed id: 24418253

Crystal structures of the F88Y obelin mutant before and after bioluminescence provide molecular insight into spectral tuning among hydromedusan photoproteins.

P.V.Natashin, S.V.Markova, J.Lee, E.S.Vysotski, Z.J.Liu.

ABSTRACT

Ca(2+) -regulated photoproteins are responsible for the bioluminescence of a variety of marine coelenterates. All hydromedusan photoproteins are a single-chain polypeptide to which 2-hydroperoxycoelenterazine is tightly but non-covalently bound. Bioluminescence results from oxidative decarboxylation of 2-hydroperoxycoelenterazine, generating protein-bound coelenteramide in an excited state. The bioluminescence spectral maxima of recombinant photoproteins vary in the range 462-495 nm, despite a high degree of identity of amino acid sequences and spatial structures of these photoproteins. Based on studies of obelin and aequorin mutants with substitution of Phe to Tyr and Tyr to Phe, respectively [Stepanyuk GA et al. (2005) FEBS Lett 579, 1008-1014], it was suggested that the spectral differences may be accounted for by an additional hydrogen bond between the hydroxyl group of a Tyr residue and an oxygen atom of the 6-(p-hydroxyphenyl) substituent of coelenterazine. Here, we report the crystal structures of two conformation states of the F88Y obelin mutant that has bioluminescence and product fluorescence spectra resembling those of aequorin. Comparison of spatial structures of the F88Y obelin conformation states with those of wild-type obelin clearly shows that substitution of Phe to Tyr does not affect the overall structures of either F88Y obelin or its product following Ca(2+) discharge, compared to the conformation states of wild-type obelin. The hydrogen bond network in F88Y obelin being due to the Tyr substitution clearly supports the suggestion that different hydrogen bond patterns near the oxygen of the 6-(p-hydroxyphenyl) substituent are the basis for spectral modifications between hydromedusan photoproteins.