Search

Symmetric proteins are currently of interest as they allow creation of larger assemblies and facilitate the incorporation of metal ions in the larger complexes. Recently this was demonstrated by the biomineralization of the cadmium-chloride nanocrystal via the Pizza designer protein. However, the mechanism behind this formation remained unclear. Here, we set out to investigate the mechanism driving the formation of this nanocrystal via truncation, mutation, and circular permutations. In addition, the interaction of other biologically relevant metal ions with these symmetric proteins to form larger symmetric complexes was also studied. The formation of the initial nanocrystal is shown to originate from steric strain, where His 58 induces a different rotameric conformation on His 73, thereby distorting an otherwise perfect planar ring of alternating cadmium and chlorine ions, resulting in the smallest nanocrystal. Similar highly symmetric complexes were also observed for the other biological relevant metal ions. However, the flexibility of the coordinating histidine residues allows each metal ion to adopt its preferred geometry leading to either monomeric or dimeric β-propeller units, where the metal ions are located at the interface between both propeller units. These results demonstrate that symmetric proteins are not only interesting to generate larger assemblies, but are also the perfect scaffold to create more complex metal based assemblies. Such metal protein assemblies may then find applications in bionanotechnology or biocatalysis. ispartof: PROTEINS-STRUCTURE FUNCTION AND BIOINFORMATICS vol:89 issue:8 pages:945-951 ispartof: location:United States status: published

Since the determination of the first molecular models of proteins there has been interest in creating proteins artificially, but such methods have only become widely successful in the last decade. Gradual improvements over a long period of time have now yielded numerous examples of non-natural proteins, many of which are built from repeated elements. In this review we discuss the design of such symmetrical proteins and their various applications in chemistry and medicine. ispartof: COMPUTATIONAL AND STRUCTURAL BIOTECHNOLOGY JOURNAL vol:18 pages:3959-3968 ispartof: location:Netherlands status: published

ispartof: JOURNAL OF CLINICAL IMMUNOLOGY vol:39 issue:2 pages:138-141 ispartof: location:Netherlands status: published

In recent years, there has been growing interest in the creation of synthetic proteins with perfect internal symmetry. Such structures can be achieved by analysing the consensus sequences of natural proteins or de novo by computational methods. Proteins with translational (polar) symmetry have found applications as artificial antibodies, while those with point (cyclic) symmetry have proved stimulating models of molecular evolution. Proteins with internal repeats can also serve as building blocks for the creation of larger symmetrical assemblies, such as cages, that may depend on and mutually organise other molecules. This has been demonstrated by the biomineralisation of the smallest nanocrystal in a designer protein complex.