The 2.2 A crystal structure of a pocilloporin pigment reveals a nonplanar chromophore conformation.
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.
Prescott
Mark
M
Department of Biochemistry and Molecular Biology, School of Biomedical Sciences, Monash University, Clayton, 3800, Victoria, Australia. mark.prescott@med.monash.au
Ling
Michael
M
Beddoe
Travis
T
Oakley
Aaron J
AJ
Dove
Sophie
S
Hoegh-Guldberg
Ove
O
Devenish
Rodney J
RJ
Rossjohn
Jamie
J
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
D049452:Green Fluorescent Proteins; D008164:Luminescent Proteins; D010860:Pigments, Biological; D000097573:Red Fluorescent Protein