Engineering allosteric control to an unregulated enzyme by transfer of a regulatory domain.
Allosteric regulation of protein function is a critical component of metabolic control. Its importance is underpinned by the diversity of mechanisms and its presence in all three domains of life. The first enzyme of the aromatic amino acid biosynthesis, 3-deoxy-D-arabino-heptulosonate 7-phosphate synthase, shows remarkable variation in allosteric response and machinery, and both contemporary regulated and unregulated orthologs have been described. To examine the molecular events by which allostery can evolve, we have generated a chimeric protein by joining the catalytic domain of an unregulated 3-deoxy-D-arabino-heptulosonate 7-phosphate synthase with the regulatory domain of a regulated enzyme. We demonstrate that this simple gene fusion event on its own is sufficient to confer functional allostery to the unregulated enzyme. The fusion protein shares structural similarities with its regulated parent protein and undergoes an analogous major conformational change in response to the binding of allosteric effector tyrosine to the regulatory domain. These findings help delineate a remarkably facile mechanism for the evolution of modular allostery by domain recruitment.
Biomolecular Interaction Centre and Department of Chemistry,  University of Canterbury, Christchurch 8140,  New Zealand.
Penelope J
PJ
Cross
Timothy M
TM
Allison
Renwick C J
RC
Dobson
Geoffrey B
GB
Jameson
Emily J
EJ
Parker
D010723:3-Deoxy-7-Phosphoheptulonate Synthase / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D000494:Allosteric Regulation; D000495:Allosteric Site; D000595:Amino Acid Sequence; D024322:Amino Acids, Aromatic / Q000096:biosynthesis; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D018360:Crystallography, X-Ray; D019143:Evolution, Molecular; D050939:Gene Fusion; D005798:Genes, Bacterial; D007700:Kinetics; D008958:Models, Molecular; D008969:Molecular Sequence Data; D011487:Protein Conformation; D015202:Protein Engineering; D055503:Protein Multimerization; D017434:Protein Structure, Tertiary; D021122:Protein Subunits; D020027:Pyrococcus furiosus / Q000201:enzymology / Q000235:genetics; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D020124:Thermotoga maritima / Q000201:enzymology / Q000235:genetics; D014443:Tyrosine / Q000378:metabolism
D024322:Amino Acids, Aromatic; D001426:Bacterial Proteins; D021122:Protein Subunits; D011993:Recombinant Fusion Proteins; D014443:Tyrosine; D010723:3-Deoxy-7-Phosphoheptulonate Synthase