biostudies-literatureUnknown96(4)Reuter WAn electrophoretically purified allophycocyanin-linker complex, AP. LC7.8, from phycobilisomes of Mastigocladus laminosus has been crystallized in the orthorhombic space group P212121. Cryocrystallographic x-ray measurements enabled the structural analysis of the complex at a resolution of 2.2 A. The asymmetric unit contains two side-to-side associated "trimeric" (alphabeta)3 allophycocyanin complexes comprising the linker polypeptide in a defined orientation inside the trimer. The linker representing a protein fold related to the prosegment of procarboxypeptidase A is in contact with only two of the three beta-subunits and directly interacts with the corresponding chromophores of these proteins. In addition to a modulation of the chromophores' spectral properties, the linker polypeptide attracts the alphabeta-subcomplexes, thereby bringing the beta-chromophores closer together. These results will enable interpretations of energy-transfer mechanisms within phycobiliproteins.Proceedings of the National Academy of Sciences of the United States of America1363-8https://www.ebi.ac.uk/biostudies/studies/S-EPMC15468biostudies-literatureStructural analysis at 2.2 A of orthorhombic crystals presents the asymmetry of the allophycocyanin-linker complex, AP.LC7.8, from phycobilisomes of Mastigocladus laminosus.PMC15468Huber RReuter WWiegand GThan MEfalseStructural analysis at 2.2 A of orthorhombic crystals presents the asymmetry of the allophycocyanin-linker complex, AP.LC7.8, from phycobilisomes of Mastigocladus laminosus.An electrophoretically purified allophycocyanin-linker complex, AP. LC7.8, from phycobilisomes of Mastigocladus laminosus has been crystallized in the orthorhombic space group P212121. Cryocrystallographic x-ray measurements enabled the structural analysis of the complex at a resolution of 2.2 A. The asymmetric unit contains two side-to-side associated "trimeric" (alphabeta)3 allophycocyanin complexes comprising the linker polypeptide in a defined orientation inside the trimer. The linker representing a protein fold related to the prosegment of procarboxypeptidase A is in contact with only two of the three beta-subunits and directly interacts with the corresponding chromophores of these proteins. In addition to a modulation of the chromophores' spectral properties, the linker polypeptide attracts the alphabeta-subcomplexes, thereby bringing the beta-chromophores closer together. These results will enable interpretations of energy-transfer mechanisms within phycobiliproteins.1999-01-01T00:00:00Z1999 Feb2025-04-04T22:05:33.511Z2019-03-27T00:17:44ZS-EPMC15468999002910.1073/pnas.96.4.1363