A PHP Error was encountered

Severity: Warning

Message: file_get_contents(https://...@gmail.com&api_key=61f08fa0b96a73de8c900d749fcb997acc09): Failed to open stream: HTTP request failed! HTTP/1.1 429 Too Many Requests

Filename: helpers/my_audit_helper.php

Line Number: 143

Backtrace:

File: /var/www/html/application/helpers/my_audit_helper.php
Line: 143
Function: file_get_contents

File: /var/www/html/application/helpers/my_audit_helper.php
Line: 209
Function: simplexml_load_file_from_url

File: /var/www/html/application/helpers/my_audit_helper.php
Line: 994
Function: getPubMedXML

File: /var/www/html/application/helpers/my_audit_helper.php
Line: 3134
Function: GetPubMedArticleOutput_2016

File: /var/www/html/application/controllers/Detail.php
Line: 574
Function: pubMedSearch_Global

File: /var/www/html/application/controllers/Detail.php
Line: 488
Function: pubMedGetRelatedKeyword

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

Insights into Flavin-based Electron Bifurcation via the NADH-dependent Reduced Ferredoxin:NADP Oxidoreductase Structure. | LitMetric

AI Article Synopsis

  • NfnAB is an important enzyme found in some anaerobic bacteria and archaea, which performs the reaction of reducing ferredoxin using NADPH, driven by a process called transhydrogenation with NAD(+).* -
  • Researchers produced the NfnAB complex from Thermotoga maritima in E. coli, and confirmed its ability to carry out this electron bifurcation process through kinetic studies and x-ray structural analysis.* -
  • The structure of NfnAB shows a specific electron transfer pathway involving key cofactors like FAD and [4Fe-4S] clusters, with a crucial amino acid, Arg(187), aiding in the required low redox potential for the reduction of ferredoxin.*

Article Abstract

NADH-dependent reduced ferredoxin:NADP oxidoreductase (NfnAB) is found in the cytoplasm of various anaerobic bacteria and archaea. The enzyme reversibly catalyzes the endergonic reduction of ferredoxin with NADPH driven by the exergonic transhydrogenation from NADPH onto NAD(+). Coupling is most probably accomplished via the mechanism of flavin-based electron bifurcation. To understand this process on a structural basis, we heterologously produced the NfnAB complex of Thermotoga maritima in Escherichia coli, provided kinetic evidence for its bifurcating behavior, and determined its x-ray structure in the absence and presence of NADH. The structure of NfnAB reveals an electron transfer route including the FAD (a-FAD), the [2Fe-2S] cluster of NfnA and the FAD (b-FAD), and the two [4Fe-4S] clusters of NfnB. Ferredoxin is presumably docked onto NfnB close to the [4Fe-4S] cluster distal to b-FAD. NAD(H) binds to a-FAD and NADP(H) consequently to b-FAD, which is positioned in the center of the NfnAB complex and the site of electron bifurcation. Arg(187) is hydrogen-bonded to N5 and O4 of the bifurcating b-FAD and might play a key role in adjusting a low redox potential of the FADH(•)/FAD pair required for ferredoxin reduction. A mechanism of FAD-coupled electron bifurcation by NfnAB is proposed.

Download full-text PDF

Source
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4571952PMC
http://dx.doi.org/10.1074/jbc.M115.656520DOI Listing

Publication Analysis

Top Keywords

electron bifurcation
16
flavin-based electron
8
nadh-dependent reduced
8
reduced ferredoxinnadp
8
ferredoxinnadp oxidoreductase
8
nfnab complex
8
electron
5
nfnab
5
insights flavin-based
4
bifurcation
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!