Using Nonnatural Amino Acids to Control Metal-Coordination Number in Three-Stranded Coiled Coils

Using nonnatural amino acids to control metal-coordination number in three-stranded coiled coils.

Identifying important structural characteristics of arsenic resistance proteins by using designed three-stranded coiled coils.

Arsenic, a contaminant of water supplies worldwide, is one of the most toxic inorganic ions. Despite arsenic's health impact, there is relatively little structural detail known about its interactions with proteins. Bacteria such as Escherichia coli have evolved arsenic resistance using the Ars operon that is regulated by ArsR, a repressor protein that dissociates from DNA when As(III) binds. Th...

Incorporation of nonnatural amino acids into proteins.

The genetic code is established by the aminoacylation of transfer RNA, reactions in which each amino acid is linked to its cognate tRNA that, in turn, harbors the nucleotide triplet (anticodon) specific to the amino acid. The accuracy of aminoacylation is essential for building and maintaining the universal tree of life. The ability to manipulate and expand the code holds promise for the develo...

Electrostatic determinants of stability in parallel 3-stranded coiled coils.

The optimal positioning of salt-bridging interactions in a parallel alpha-helical homotrimeric coiled coil has been explored in a metal ion-assembled polypeptide trimer of 60 residues; arginine-glutamate pairs are more stabilizing than the corresponding lysine-glutamate pairs, and optimal stabilization is obtained with positively charged arginine residues at the c positions of the alpha-helical...

A switch between two-, three-, and four-stranded coiled coils in GCN4 leucine zipper mutants.

Coiled-coil sequences in proteins consist of heptad repeats containing two characteristic hydrophobic positions. The role of these buried hydrophobic residues in determining the structures of coiled coils was investigated by studying mutants of the GCN4 leucine zipper. When sets of buried residues were altered, two-, three-, and four-helix structures were formed. The x-ray crystal structure of ...