标题：Structural analysis at 2.2 Å of orthorhombic crystals presents the asymmetry of the allophycocyanin–linker complex, AP⋅LC7.8, from phycobilisomes of Mastigocladus laminosus
期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：1999
卷号：96
期号：4
页码：1363-1368
DOI：10.1073/pnas.96.4.1363
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：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" ({beta})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 {beta}-subcomplexes, thereby bringing the {beta}-chromophores closer together. These results will enable interpretations of energy-transfer mechanisms within phycobiliproteins.
关键词：cyanobacteria ; linker polypeptides ; crystallization ; photosynthesis ; energy transfer
