8II8

X-ray crystal structure of pink-colored protein from Pleurotus salmoneostramineus in complex with natural chromophore

Summary for 8II8

• Entry DOI: 10.2210/pdb8ii8/pdb
• Descriptor: Chromoprotein, ACETYL GROUP, (2E,5E,7Z,9E,11E,13E,15Z,17E,19Z,21E,23E)-24-methyl-25-oxohexacosa-2,5,7,9,11,13,15,17,19,21,23-undecaenoic acid, ... (4 entities in total)
• Functional Keywords: chromoprotein, mushroom, lipid binding protein
• Biological source: Pleurotus salmoneostramineus
• Total number of polymer chains: 1
• Total formula weight: 24183.02

Authors

Ihara, M.,Fukuta, Y.,Shirasaka, N. (deposition date: 2023-02-24, release date: 2024-08-14, Last modification date: 2024-08-21)

Primary citation

Ihara, M.,Tsuchida, N.,Sumida, M.,Himiyama, T.,Kitayama, T.,Shirasaka, N.,Fukuta, Y.
Crystal Structure of the Native Chromoprotein from Pleurotus salmoneostramineus Provides Insights into the Pigmentation Mechanism.
J.Agric.Food Chem., 72:17626-17632, 2024

PubMed Abstract: The pink-colored protein from the fungus (PsPCP) possesses unusual primary sequences with little resemblance to those of known proteins and exhibits a red color in aqueous solution. To understand the pigmentation mechanism of PsPCP, we elucidated the X-ray crystal structure of the native PsPCP. We identified a highly conjugated polyene ligand 2-dehydro-3-deoxylaetiporic acid A as a chromophore ligand, whose solution exhibits yellow. The crystal structure of PsPCP indicated that the ligand is secured in the central cavity and anchored at both termini by hydrophilic interactions and that surrounding residues show CH-pi and C-H···O hydrogen bondings. Geometrical analyses of the bound ligand demonstrated that the conjugated C-C and C═C bonds exhibit similar bond distances. The result indicated enhanced electron delocalization within the conjugated CC bond system, resulting in a redshift of the chromophore ligand. The computational estimates of the UV-vis spectra support the view that the electron delocalization within the conjugated CC bonds system of the bound ligand, induced by the specific ligand geometry within a limited space of PsPCP cavity, is responsible for the red pigmentation of PsPCP. Thus, we propose that the coloring mechanism of PsPCP, which constrains the geometry of a highly conjugated polyene ligand, is a novel type of pigment chemistry.

PubMed: 39073883
DOI: 10.1021/acs.jafc.4c02951

Experimental method

X-RAY DIFFRACTION (1.25 Å)