The molecular pathway for the allosteric regulation of tryptophan synthase.

@article{citeulike:1713672, abstract = {The pyridoxal 5'-phosphate (PLP)-dependent tryptophan synthase is a alpha(2)beta(2) complex. The alpha-beta subunit interaction plays a critical role both in the reciprocal activation of the individual subunits and in the allosteric regulation. We have investigated whether mutations of alpha loop6 Gly(181) and beta helix6 Ser(178) affect intersubunit communication. The loss of the hydrogen bond between these residues, achieved by proline substitution, does not significantly influence the intersubunit catalytic activation, but completely abolishes ligand-induced intersubunit signaling. The comparison of the crystal structure of the wild type and beta Ser(178)Pro mutant, in the absence and presence of alpha-subunit ligands, indicates that the removal of the interaction between beta Ser(178) and alpha Gly(181) strongly affects the equilibrium between active (closed) and inactive (open) conformations of the alpha-active site, the latter being stabilized in both mutants.}, address = {Department of Biochemistry and Molecular Biology, University of Parma, Parma 43100, Italy.}, author = {Raboni, S. and Pioselli, B. and Bettati, S. and Mozzarelli, A. }, citeulike-article-id = {1713672}, issn = {0006-3002}, journal = {Biochim Biophys Acta}, keywords = {metabolism, regulation}, month = {April}, number = {1-2}, pages = {157--160}, posted-at = {2007-10-01 05:55:39}, priority = {2}, title = {The molecular pathway for the allosteric regulation of tryptophan synthase.}, url = {http://view.ncbi.nlm.nih.gov/pubmed/12686126}, volume = {1647}, year = {2003} }

TY - JOUR ID - citeulike:1713672 L3 - citeulike-article-id:1713672 TI - The molecular pathway for the allosteric regulation of tryptophan synthase. JF - Biochim Biophys Acta VL - 1647 IS - 1-2 SP - 157 EP - 160 AD - Department of Biochemistry and Molecular Biology, University of Parma, Parma 43100, Italy. SN - 0006-3002 N2 - The pyridoxal 5'-phosphate (PLP)-dependent tryptophan synthase is a alpha(2)beta(2) complex. The alpha-beta subunit interaction plays a critical role both in the reciprocal activation of the individual subunits and in the allosteric regulation. We have investigated whether mutations of alpha loop6 Gly(181) and beta helix6 Ser(178) affect intersubunit communication. The loss of the hydrogen bond between these residues, achieved by proline substitution, does not significantly influence the intersubunit catalytic activation, but completely abolishes ligand-induced intersubunit signaling. The comparison of the crystal structure of the wild type and beta Ser(178)Pro mutant, in the absence and presence of alpha-subunit ligands, indicates that the removal of the interaction between beta Ser(178) and alpha Gly(181) strongly affects the equilibrium between active (closed) and inactive (open) conformations of the alpha-active site, the latter being stabilized in both mutants. KW - metabolism KW - regulation AU - Raboni, S AU - Pioselli, B AU - Bettati, S AU - Mozzarelli, A PY - 2003/04/11/ UR - http://view.ncbi.nlm.nih.gov/pubmed/12686126 ER -