5lyc
Cytochrome c in complex with phosphonato-calix[6]areneCytochrome c in complex with phosphonato-calix[6]arene
Structural highlights
FunctionCYC1_YEAST Electron carrier protein. The oxidized form of the cytochrome c heme group can accept an electron from the heme group of the cytochrome c1 subunit of cytochrome reductase. Cytochrome c then transfers this electron to the cytochrome oxidase complex, the final protein carrier in the mitochondrial electron-transport chain. Publication Abstract from PubMedComplex formation between cationic cytochrome c and the water-soluble, poly-anionic p-phosphonatocalix[6]arene (pclx6 ) was investigated. A crystal structure (at 1.8 A resolution) revealed a remarkable dimeric disc of pclx6 that acts like glue to mediate a symmetric (C2 ) protein dimer. The calixarene disc has a diameter of about 1.5 nm and masks about 360 A2 of protein surface. The key protein-calixarene contacts occur via two linchpin lysines, with additional contacts provided by a small hydrophobic patch. The protein-calixarene supramolecular assemblies were observed in solution by size-exclusion chromatography with multi-angle light scattering and NMR spectroscopy. Using isothermal titration calorimetry and NMR data, an apparent Kd in the low micromolar range was determined for the charge-rich protein-calixarene complex. In contrast to p-sulfonatocalix[4]arene, the larger pclx6 has a single, well-defined binding site that mediates the assembly of cytochrome c in solution. Protein Dimerization on a Phosphonated Calix[6]arene Disc.,Rennie ML, Doolan AM, Raston CL, Crowley PB Angew Chem Int Ed Engl. 2017 May 8;56(20):5517-5521. doi: 10.1002/anie.201701500., Epub 2017 Apr 13. PMID:28407337[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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