title: A superprotein triangle driven by nickel(II) coordination: exploiting non-natural metal ligands in protein self-assembly.
abstract: We previously devised a strategy (metal-directed protein self-assembly, MDPSA) that utilizes the simultaneous stability, lability, and directionality of metal-ligand bonds to drive protein-protein interactions. Here we show that both the structural and functional scopes of MDPSA can be broadened by incorporation of non-natural metal-chelating ligands onto protein surfaces. A cytochrome cb(562) variant, MBP-Phen1, which features a covalently attached phenanthroline (Phen) group on its surface, self-assembles into an unusual triangular architecture (Ni(3):MBP-Phen1(3)) upon binding Ni as a result of specific Phen-protein interactions. The crystal structure of Ni(3):MBP-Phen1(3) reveals that the Phen group is buried in a small pocket on the protein surface, which results in an unsaturated Ni coordination environment.
authors.affiliation: Department of Chemistry and Biochemistry, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093-0356, USA.
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Radford
authors.forename: F Akif
authors.initials: FA
authors.lastname: Tezcan
mesh_terms: D001665:Binding Sites; D018360:Crystallography, X-Ray; D003573:Cytochrome b Group / Q000737:chemistry*; D004926:Escherichia coli / Q000737:chemistry*; D029968:Escherichia coli Proteins / Q000737:chemistry*; D008024:Ligands; D008958:Models, Molecular; D009532:Nickel / Q000737:chemistry*; D010618:Phenanthrolines / Q000737:chemistry*; D011485:Protein Binding; D011487:Protein Conformation; D055503:Protein Multimerization; D013816:Thermodynamics
chemical_list: D003573:Cytochrome b Group; D029968:Escherichia coli Proteins; D008024:Ligands; D010618:Phenanthrolines; D009532:Nickel; C017850:cytochrome b562, E coli