title: The 2.2 A crystal structure of a pocilloporin pigment reveals a nonplanar chromophore conformation.
abstract: Reef-building corals contain host pigments, termed pocilloporins, that function to regulate the light environment of their resident microalgae by acting as a photoprotectant in excessive sunlight. We have determined the crystal structure of an intensely blue, nonfluorescent pocilloporin to 2.2 A resolution and a genetically engineered fluorescent variant to 2.4 A resolution. The pocilloporin chromophore structure adopts a markedly different conformation in comparison with the DsRed chromophore, despite the chromophore sequences (Gln-Tyr-Gly) being identical; the tyrosine ring of the pocilloporin chromophore is noncoplanar and in the trans configuration. Furthermore, the fluorescent variant adopted a noncoplanar chromophore conformation. The data presented here demonstrates that the conformation of the chromophore is highly dependent on its immediate environment.
authors.affiliation: Department of Biochemistry and Molecular Biology, School of Biomedical Sciences, Monash University, Clayton, 3800, Victoria, Australia. mark.prescott@med.monash.au
authors.forename: Mark
authors.initials: M
authors.lastname: Prescott
authors.forename: Michael
authors.initials: M
authors.lastname: Ling
authors.forename: Travis
authors.initials: T
authors.lastname: Beddoe
authors.forename: Aaron J
authors.initials: AJ
authors.lastname: Oakley
authors.forename: Sophie
authors.initials: S
authors.lastname: Dove
authors.forename: Ove
authors.initials: O
authors.lastname: Hoegh-Guldberg
authors.forename: Rodney J
authors.initials: RJ
authors.lastname: Devenish
authors.forename: Jamie
authors.initials: J
authors.lastname: Rossjohn
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D037421:Anthozoa / Q000737:chemistry*; D018360:Crystallography, X-Ray; D049452:Green Fluorescent Proteins; D008164:Luminescent Proteins / Q000235:genetics; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D010860:Pigments, Biological / Q000737:chemistry* / Q000235:genetics; D011487:Protein Conformation; D000097573:Red Fluorescent Protein
chemical_list: D049452:Green Fluorescent Proteins; D008164:Luminescent Proteins; D010860:Pigments, Biological; D000097573:Red Fluorescent Protein