A PHP Error was encountered

Severity: Warning

Message: file_get_contents(https://...@pubfacts.com&api_key=b8daa3ad693db53b1410957c26c9a51b4908&a=1): Failed to open stream: HTTP request failed! HTTP/1.1 429 Too Many Requests

Filename: helpers/my_audit_helper.php

Line Number: 176

Backtrace:

File: /var/www/html/application/helpers/my_audit_helper.php
Line: 176
Function: file_get_contents

File: /var/www/html/application/helpers/my_audit_helper.php
Line: 250
Function: simplexml_load_file_from_url

File: /var/www/html/application/helpers/my_audit_helper.php
Line: 1034
Function: getPubMedXML

File: /var/www/html/application/helpers/my_audit_helper.php
Line: 3152
Function: GetPubMedArticleOutput_2016

File: /var/www/html/application/controllers/Detail.php
Line: 575
Function: pubMedSearch_Global

File: /var/www/html/application/controllers/Detail.php
Line: 489
Function: pubMedGetRelatedKeyword

File: /var/www/html/index.php
Line: 316
Function: require_once

Molecular determinants of permeation in a fluoride-specific ion channel. | LitMetric

Molecular determinants of permeation in a fluoride-specific ion channel.

Elife

Department of Biochemistry, Howard Hughes Medical Institute, Brandeis University, Waltham, United States.

Published: September 2017

Fluoride ion channels of the Fluc family combat toxicity arising from accumulation of environmental F. Although crystal structures are known, the densely packed pore region has precluded delineation of the ion pathway. Here we chart out the Fluc pore and characterize its chemical requirements for transport. A ladder of H-bond donating residues creates a 'polar track' demarking the ion-conduction pathway. Surprisingly, while track polarity is well conserved, polarity is nonetheless functionally dispensable at several positions. A threonine at one end of the pore engages in vital interactions through its β-branched methyl group. Two critical central phenylalanines that directly coordinate F through a quadrupolar-ion interaction cannot be functionally substituted by aromatic, non-polar, or polar sidechains. The only functional replacement is methionine, which coordinates F through its partially positive γ-methylene in mimicry of phenylalanine's quadrupolar interaction. These results demonstrate the unusual chemical requirements for selectively transporting the strongly H-bonding F anion.

Download full-text PDF

Source
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5636608PMC
http://dx.doi.org/10.7554/eLife.31259DOI Listing

Publication Analysis

Top Keywords

chemical requirements
8
molecular determinants
4
determinants permeation
4
permeation fluoride-specific
4
fluoride-specific ion
4
ion channel
4
channel fluoride
4
fluoride ion
4
ion channels
4
channels fluc
4

Similar Publications

Want AI Summaries of new PubMed Abstracts delivered to your In-box?

Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!