Three-dimensional structures of C-phycocyanin and B-phycoerythrin at 5-A resolution.
1980; Elsevier BV; Volume: 255; Issue: 11 Linguagem: Inglês
10.1016/s0021-9258(19)70752-2
ISSN1083-351X
AutoresRobert G. Fisher, Neill Woods, H. Fuchs, Robert M. Sweet,
Tópico(s)Photoreceptor and optogenetics research
ResumoSingle crystal x-ray diffraction studies are proceeding on two phycobiliproteins: C-Phycocyanin from Anabaena variabilis and B-Phycoerythrin from Porphyridium cruenturn C-Phycocyanin consists of six a and six fl subunits.A three-dimensional x-ray dieaction study of this light-harvesting protein (P63; a = b = 154.1 A, c = 40.1 A) at 6-A resolution shows that the molecule is 110 A in diameter, 40 A thick, with a 20-A diameter central channel.It can be divided into three separate domains related by the crystallographic 3 and contains long, columnar regions of density, presumed to represent a helix.B-Phycoe hrin is composed of 6a, Sa, and a y subunit.A 5.25-T resolution study of this protein (R3, a = b = 189 A, c = 60 A) indicates that the molecule is 107 A in diameter and 55 A thick, has 32-D3 symmetry, and can be divided into six regions.The y chain lies on a crystallographic 3 and undergoes symmetric disordering.A region of low and unstructured density in the center of the molecule is presumably occupied by this y chain.These two low resolution structures are compared with regard to differences in quaternary structure.* The abbreviations used are: PEB,
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