Divergent evolution of (betaalpha)8-barrel enzymes.
The (betaalpha)8-barrel is the most versatile and most frequently encountered fold among enzymes. It is an interesting question how the contemporary (betaalpha)8-barrels are evolutionarily related and by which mechanisms they evolved from more simple precursors. Comprehensive comparisons of amino acid sequences and three-dimensional structures suggest that a large fraction of the known (betaalpha)8-barrels have divergently evolved from a common ancestor. The mutational interconversion of enzymatic activities of several (betaalpha)8-barrels further supports their common evolutionary origin. Moreover, the high structural similarity between the N- and C-terminal (betaalpha)4 units of two (betaalpha)8-barrel enzymes from histidine biosynthesis indicates that the contemporary proteins evolved by tandem duplication and fusion of the gene of an ancestral 'half-barrel' precursor. In support of this hypothesis, recombinantly produced 'half-barrels' were shown to be folded, dimeric proteins.
Henn-Sax
M
M
Institut für Biochemie, Universität zu Köln, Germany.
Höcker
B
B
Wilmanns
M
M
Sterner
R
R
D005075:Biological Evolution; D004798:Enzymes / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D010710:Phosphates / Q000378:metabolism; D011487:Protein Conformation
D004798:Enzymes; D010710:Phosphates