High-resolution crystal structure of an artificial (betaalpha)(8)-barrel protein designed from identical half-barrels.
Ample evidence suggests that the ubiquitous (betaalpha)(8)-barrel enzyme fold has evolved by the duplication and fusion of an ancestral (betaalpha)(4)-half-barrel. To reconstruct this process in the laboratory with a model protein, we earlier fused two copies of the C-terminal half-barrel HisF-C of imidazole glycerol phosphate synthase (HisF) and stepwise stabilized the resulting HisF-CC construct. We now further increased its stability and solubility by introducing two additional amino acid exchanges, which allowed us to crystallize the resulting artificial (betaalpha)(8)-barrel protein HisF-C***C. The analysis of its X-ray structure at 2.1 A resolution reveals a striking similarity to wild-type HisF, helps us to understand its improved stability, and provides further insights into the evolution of (betaalpha)(8)-barrel proteins.
Höcker
Birte
B
Max Planck Institute for Developmental Biology, Spemannstrasse 35, D-72076 Tubingen, Germany. birte.hoecker@tuebingen.mpg.de
Lochner
Adriane
A
Seitz
Tobias
T
Claren
Jörg
J
Sterner
Reinhard
R
D000619:Aminohydrolases / Q000737:chemistry*; D018360:Crystallography, X-Ray; D017433:Protein Structure, Secondary; D011994:Recombinant Proteins / Q000737:chemistry*
D011994:Recombinant Proteins; C087227:imidazole glycerol phosphate synthase; D000619:Aminohydrolases