The Effect of Carboxyl-terminal Mutagenesis of G(t)alpha on Rhodopsin and Guanine Nucleotide Binding Export

@article{citeulike:3431841, abstract = {The carboxyl terminus of G protein [alpha] subunits plays an important role in receptor recognition. To identify the amino acids that participate in this interaction, COOH-terminal mutants of [alpha][(t)] (the transducin [alpha] subunit) were expressed in vitro and analyzed for their ability to interact with rhodopsin and to bind guanine nucleotide. Gly-348, the reported site of a [beta] turn, was replaced with other neutral amino acids without severely affecting rhodopsin binding. However, proline substitution abolished rhodopsin interaction, suggesting that flexibility is important at this site. A comparison between C347Y, which lost both rhodopsin and guanine nucleotide binding, and a mutant substituted with [alpha][(q)] sequence (D346E/C347Y/G348N/F350V), in which guanine nucleotide binding was restored, implies that distinct motifs maintain the structure of the [alpha] subunit and are necessary for selective interaction with receptors. Surprisingly, mutants L344A, L349A, F350stop, and stop351A demonstrated a parallel loss of rhodopsin and guanine nucleotide binding. Altered profiles of L344A and F350stop on sucrose density gradients indicate that these mutants may undergo denaturation. The equivalent of [alpha][(t)]L344A generated in [alpha][(s)] and [alpha][(i)] did not show such a severe loss of guanine nucleotide binding, revealing that the [alpha][(t)] carboxyl terminus is unique in its susceptibility to changes in amino acid sequence. 10.1074/jbc.270.52.31052}, author = {Osawa, Shoji and Weiss, Ellen R.}, citeulike-article-id = {3431841}, citeulike-linkout-0 = {http://dx.doi.org/10.1074/jbc.270.52.31052}, citeulike-linkout-1 = {http://www.jbc.org/cgi/content/abstract/270/52/31052}, citeulike-linkout-2 = {http://view.ncbi.nlm.nih.gov/pubmed/8537363}, citeulike-linkout-3 = {http://www.hubmed.org/display.cgi?uids=8537363}, day = {29}, doi = {10.1074/jbc.270.52.31052}, journal = {J. Biol. Chem.}, keywords = {paper1}, month = {December}, number = {52}, pages = {31052--31058}, posted-at = {2008-10-21 00:43:41}, priority = {2}, title = {The Effect of Carboxyl-terminal Mutagenesis of G(t)alpha on Rhodopsin and Guanine Nucleotide Binding}, url = {http://dx.doi.org/10.1074/jbc.270.52.31052}, volume = {270}, year = {1995} }

TY - JOUR ID - citeulike:3431841 L3 - citeulike-article-id:3431841 N2 - The carboxyl terminus of G protein [alpha] subunits plays an important role in receptor recognition. To identify the amino acids that participate in this interaction, COOH-terminal mutants of [alpha][(t)] (the transducin [alpha] subunit) were expressed in vitro and analyzed for their ability to interact with rhodopsin and to bind guanine nucleotide. Gly-348, the reported site of a [beta] turn, was replaced with other neutral amino acids without severely affecting rhodopsin binding. However, proline substitution abolished rhodopsin interaction, suggesting that flexibility is important at this site. A comparison between C347Y, which lost both rhodopsin and guanine nucleotide binding, and a mutant substituted with [alpha][(q)] sequence (D346E/C347Y/G348N/F350V), in which guanine nucleotide binding was restored, implies that distinct motifs maintain the structure of the [alpha] subunit and are necessary for selective interaction with receptors. Surprisingly, mutants L344A, L349A, F350stop, and stop351A demonstrated a parallel loss of rhodopsin and guanine nucleotide binding. Altered profiles of L344A and F350stop on sucrose density gradients indicate that these mutants may undergo denaturation. The equivalent of [alpha][(t)]L344A generated in [alpha][(s)] and [alpha][(i)] did not show such a severe loss of guanine nucleotide binding, revealing that the [alpha][(t)] carboxyl terminus is unique in its susceptibility to changes in amino acid sequence. 10.1074/jbc.270.52.31052 IS - 52 JF - J. Biol. Chem. EP - 31058 TI - The Effect of Carboxyl-terminal Mutagenesis of G(t)alpha on Rhodopsin and Guanine Nucleotide Binding VL - 270 SP - 31052 KW - paper1 AU - Osawa, Shoji AU - Weiss, Ellen PY - 1995/12/29/ UR - http://dx.doi.org/10.1074/jbc.270.52.31052 ER -