Dataset Information

Defining the roles of Asn-128, Glu-129 and Phe-130 in loop A of the 5-HT3 receptor.

ABSTRACT: The ligand binding pocket of Cys-loop receptors consists of a number of binding loops termed A-F. Here we examine the 5-HT3 receptor loop A residues Asn-128, Glu-129 and Phe-130 using modelling, mutagenesis, radioligand binding and functional studies on HEK 293 cells. Replacement of Asn-128 results in receptors that have wild type [3H]granisetron binding characteristics but large changes (ranging from a five-fold decrease to a 1500-fold increase) in the 5-HT EC50 when compared to wild type receptors. Phe-130 mutant receptors show both increases and decreases in Kd and EC50 values, depending on the amino acid substituted. The most critical of these residues appears to be Glu-129; its replacement with a range of other amino acids results in non-binding and non-functional receptors. Lack of binding and function in some, but not all, of these receptors is due to poor membrane expression. These data suggest that Glu-129 is important primarily for receptor expression, although it may also play a role in ligand binding; Phe-130 is important for both ligand binding and receptor function, and Asn-128 plays a larger role in receptor function than ligand binding. In light of these results, we have created two new homology models of the 5-HT3 receptor, with alternative positions of loop A. In our preferred model Glu-129 and Phe-130 contribute to the binding site, while the location of Asn-128 immediately behind the binding pocket could contribute to the conformation changes that result in receptor gating. This study provides a new model of the 5-HT3 receptor binding pocket, and also highlights the importance of experimental data to support modelling studies.

SUBMITTER: Sullivan NL

PROVIDER: S-EPMC2649376 | biostudies-literature | 2006 Sep-Oct

REPOSITORIES: biostudies-literature

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Defining the roles of Asn-128, Glu-129 and Phe-130 in loop A of the 5-HT3 receptor.

Sullivan Nora L NL Thompson Andrew J AJ Price Kerry L KL Lummis Sarah C R SC

Molecular membrane biology 20060901 5

The ligand binding pocket of Cys-loop receptors consists of a number of binding loops termed A-F. Here we examine the 5-HT3 receptor loop A residues Asn-128, Glu-129 and Phe-130 using modelling, mutagenesis, radioligand binding and functional studies on HEK 293 cells. Replacement of Asn-128 results in receptors that have wild type [3H]granisetron binding characteristics but large changes (ranging from a five-fold decrease to a 1500-fold increase) in the 5-HT EC50 when compared to wild type recep ...[more]

PMID: 17060161

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Project description:INTRODUCTION:Pharmacists are uniquely placed in the community to be of assistance to disaster-affected patients. However, the roles undertaken by pharmacists in disasters are identified based on their own experiences and networks. There is currently no definition or acknowledgment of pharmacists' roles in disasters. OBJECTIVE:To acquire consensus from an expert panel of key opinion leaders within the field of disaster health on pharmacists' roles in disasters throughout the four disaster phases-prevention, preparedness, response, and recovery. METHODS:A Delphi study consisting of three rounds of online surveys was utilised. Twenty-four key opinion leaders were contacted, with 15 completing all three rounds. The 15 expert panellists were presented with 46 roles identified in the literature and asked to rank their opinions on a 5-point Likert scale. This study used an international, all-hazard, and multijurisdictional approach. Consensus was benchmarked at 80% and any role which did not reach consensus was re-queried in the subsequent round. The third round provided the results of the Delphi study and sought commentary on the acceptance or rejection of the roles. RESULTS:Of the 46 roles provided to the expert panel, 43 roles were accepted as roles pharmacists are capable of undertaking in a disaster. There were five roles for the prevention phase, nine for the preparedness phase, 21 for the response phase, and eight for the recovery phase. The experts were asked to prioritise the top five roles for each of the disaster phases. The three roles which did not make consensus were deemed to be specialised roles for disaster pharmacists and not generalisable to the broader pharmacy profession. CONCLUSION:This study identifies pharmacists' roles in disasters which have been accepted by the international disaster health community. The international key opinion leaders recommended that pharmacists could be undertaking 43 roles in a disaster, however, this is dependent on individual jurisdiction considerations. Pharmacy professional associations need to advocate to policymakers for legislative support and to ensure pharmacists are equipped with the training and education required to undertake these roles within specific jurisdictions.

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Dataset Information

Defining the roles of Asn-128, Glu-129 and Phe-130 in loop A of the 5-HT3 receptor.

Publications

Defining the roles of Asn-128, Glu-129 and Phe-130 in loop A of the 5-HT3 receptor.

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