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    <admin>
        <current_status>
            <date>2026-08-12</date>
            <code>REL</code>
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        </current_status>
        <revision_history>
            <revision version="1.0" date="2021-01-20">
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                        <revision_group>EXPERIMENTAL_SUMMARY</revision_group>
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                            <category>em_admin</category>
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                    <model>
                        <revision_type>REMEDIATION</revision_type>
                        <provider>REPOSITORY</provider>
                        <description>Metalloprotein remediation</description>
                        <revision_group>STRUCTURE_SUMMARY</revision_group>
                        <categories>
                            <category>em_admin</category>
                            <category>pdbx_entry_details</category>
                            <category>pdbx_modification_feature</category>
                            <category>pdbx_nonpoly_atom_coordination</category>
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                            <item>_em_admin.last_update</item>
                            <item>_pdbx_entry_details.has_protein_modification</item>
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        </revision_history>
        <sites>
            <deposition>RCSB</deposition>
            <last_processing>RCSB</last_processing>
        </sites>
        <key_dates>
            <deposition>2020-11-08</deposition>
            <header_release>2021-01-20</header_release>
            <map_release>2021-01-20</map_release>
            <update>2026-08-12</update>
        </key_dates>
        <grant_support>
            <grant_reference>
                <funding_body>Department of Energy (DOE, United States)</funding_body>
                <code>DE-SC0020085</code>
                <country>United States</country>
            </grant_reference>
            <grant_reference>
                <funding_body>Department of Energy (DOE, United States)</funding_body>
                <code>DE-FG02-95ER20175</code>
                <country>United States</country>
            </grant_reference>
        </grant_support>
        <title>Electron bifurcating flavoprotein Fix/EtfABCX</title>
        <authors_list>
            <author>Feng X</author>
            <author>Li H</author>
        </authors_list>
        <keywords>membrane-associated, flavin based electron bifurcation, FLAVOPROTEIN, FLAVOPROTEIN-Oxidoreductase complex</keywords>
    </admin>
    <crossreferences>
        <citation_list>
            <primary_citation>
                <journal_citation published="true">
                    <author ORCID="0000-0002-4441-3152" order="1">Feng X</author>
                    <author ORCID="0000-0002-3694-1799" order="2">Schut GJ</author>
                    <author order="3">Lipscomb GL</author>
                    <author ORCID="0000-0001-8085-8928" order="4">Li H</author>
                    <author ORCID="0000-0002-9796-5014" order="5">Adams MWW</author>
                    <title>Cryoelectron microscopy structure and mechanism of the membrane-associated electron-bifurcating flavoprotein Fix/EtfABCX.</title>
                    <journal_abbreviation>Proc.Natl.Acad.Sci.USA</journal_abbreviation>
                    <country>US</country>
                    <volume>118</volume>
                    <year>2021</year>
                    <external_references type="PUBMED">33372143</external_references>
                    <external_references type="DOI">doi:10.1073/pnas.2016978118</external_references>
                    <external_references type="ISSN">1091-6490</external_references>
                    <external_references type="CSD">0040</external_references>
                    <external_references type="ASTM">PNASA6</external_references>
                </journal_citation>
            </primary_citation>
        </citation_list>
        <pdb_list>
            <pdb_reference>
                <pdb_id>7koe</pdb_id>
                <relationship>
                    <in_frame>FULLOVERLAP</in_frame>
                </relationship>
            </pdb_reference>
        </pdb_list>
        <other_db_list>
            <db_reference>
                <db_name>EMDB</db_name>
                <accession_id>EMD-22973</accession_id>
                <content_type>associated EM volume</content_type>
                <details>Electron bifurcating flavoprotein Fix/EtfABCX</details>
            </db_reference>
        </other_db_list>
    </crossreferences>
    <sample>
        <name>octameric complex of electron bifurcating flavoprotein Fix/EtfABCX</name>
        <supramolecule_list>
            <complex_supramolecule supramolecule_id="1">
                <name>octameric complex of electron bifurcating flavoprotein Fix/EtfABCX</name>
                <parent>0</parent>
                <macromolecule_list>
                    <macromolecule>
                        <macromolecule_id>1</macromolecule_id>
                    </macromolecule>
                    <macromolecule>
                        <macromolecule_id>2</macromolecule_id>
                    </macromolecule>
                    <macromolecule>
                        <macromolecule_id>3</macromolecule_id>
                    </macromolecule>
                    <macromolecule>
                        <macromolecule_id>4</macromolecule_id>
                    </macromolecule>
                </macromolecule_list>
                <natural_source database="NCBI">
                    <organism ncbi="243274">Thermotoga maritima MSB8</organism>
                </natural_source>
            </complex_supramolecule>
        </supramolecule_list>
        <macromolecule_list>
            <protein_or_peptide macromolecule_id="1">
                <name>Electron transfer flavoprotein, beta subunit</name>
                <natural_source database="NCBI">
                    <organism ncbi="243274">Thermotoga maritima (strain ATCC 43589 / MSB8 / DSM 3109 / JCM 10099)</organism>
                    <strain>ATCC 43589 / MSB8 / DSM 3109 / JCM 10099</strain>
                </natural_source>
                <molecular_weight>
                    <theoretical units="MDa">0.033003957</theoretical>
                </molecular_weight>
                <number_of_copies>2</number_of_copies>
                <recombinant_expression database="NCBI">
                    <recombinant_organism ncbi="1185654">Pyrococcus furiosus COM1</recombinant_organism>
                </recombinant_expression>
                <enantiomer>LEVO</enantiomer>
                <sequence>
                    <string>MAHHHHHHHHHANVVVCIKQVPDTTNVRIDRKTNNLVREGVPSIINPDDERALELASQLKEKFGATVYVITMGPPQAKEA
LKDAIAFGLDEAVHLSDRTFAGADTLATTYTLYWGIKKIEERIGKIDLILTGKQAVDGDTGQVGPGLATRFGYALGAYVV
RIEEIDPEKKEMVIVRRLDQGFEKIRLKLPAVLTITDELNKPRYADLPNLIRAIRYEPIVWTHKDLGLDPKKCGFFGSPT
RVVSTNIPPARKGGDIISKNEDPEVAAEKLIEALKKFEAVRLVEALKPVLEGEKDE</string>
                    <external_references type="UNIPROTKB">Q9X1L6</external_references>
                </sequence>
            </protein_or_peptide>
            <protein_or_peptide macromolecule_id="2">
                <name>Electron transfer flavoprotein, alpha subunit</name>
                <natural_source database="NCBI">
                    <organism ncbi="243274">Thermotoga maritima (strain ATCC 43589 / MSB8 / DSM 3109 / JCM 10099)</organism>
                    <strain>ATCC 43589 / MSB8 / DSM 3109 / JCM 10099</strain>
                </natural_source>
                <molecular_weight>
                    <theoretical units="MDa">0.036801758</theoretical>
                </molecular_weight>
                <number_of_copies>2</number_of_copies>
                <recombinant_expression database="NCBI">
                    <recombinant_organism ncbi="1185654">Pyrococcus furiosus COM1</recombinant_organism>
                </recombinant_expression>
                <enantiomer>LEVO</enantiomer>
                <sequence>
                    <string>MSEKKIIFVLIEHHGGKAHPVSWELIGKARDLASKLENSEVWGVLLGEGLESVAKEAIQRGADKVLYVKNREFNTYVNYL
YKKALVDMVRKYRPEIFLIGATLEGRELAGMVATELETGLTADCTGLDIIPDKKLLAMTRPTFGGNLMATIMCPDHRPQM
ATVRPGVMKELPPDPERTGEIIEEEYDLGTFDKLIEILETIPLQTQVNLEYAPVVVAGGKGVGGPEGFKKLKELADLLGG
EVGASRAAVKAGWISPEHQVGQTGKTVRPVLYFACGISGAIQHVVGIKESEIIVAINIDEKAPIFDIADIGIVGDLHKVV
PALTAKLRELLNKSGVKK</string>
                    <external_references type="UNIPROTKB">R4P3F4</external_references>
                </sequence>
            </protein_or_peptide>
            <protein_or_peptide macromolecule_id="3">
                <name>Electron transfer flavoprotein-quinone oxidoreductase FixC</name>
                <natural_source database="NCBI">
                    <organism ncbi="243274">Thermotoga maritima (strain ATCC 43589 / MSB8 / DSM 3109 / JCM 10099)</organism>
                    <strain>ATCC 43589 / MSB8 / DSM 3109 / JCM 10099</strain>
                </natural_source>
                <molecular_weight>
                    <theoretical units="MDa">0.049040772999999996</theoretical>
                </molecular_weight>
                <number_of_copies>2</number_of_copies>
                <recombinant_expression database="NCBI">
                    <recombinant_organism ncbi="1185654">Pyrococcus furiosus COM1</recombinant_organism>
                </recombinant_expression>
                <enantiomer>LEVO</enantiomer>
                <sequence>
                    <string>MKIEFDVVVVGAGPSGLSCAYVLAKNGLKVAVVEKGEYPGSKNVMGGVLYVHPLKEIMPDFLEKAANSKALERNVIEQNL
WLLGNEGVIKIGHRNVEWKENPNAFTVLRANFDRWFAQEVEKAGALIIPKTKVEDFLRNEKGEIAGVVTSRPKGEIHSKA
VVIAEGVNPILTMKAGLRKEDLKPHMVAVAVKEVISVPEDVVNRVFGVEGNDGATIELLGSWSEGMFGMGFLYANRSSVS
LGCGVLLEDLRKKKIKPYQLLENLKNHPVISDMLGEYRNNTMEYLAHLIPEGGYYAMPKVYGDRVLVCGDAAMLVNSIHR
EGSNHAITSGRLAAETLLEAFEKGDFSEKILKNYYLRLKESFILKDLEKYKDLMPTMEKNHQFVEIYPDLANDALKRFLQ
VDGTPKWDVQKQIADMVLSRRSLIGISLDLLRFWRAVR</string>
                    <external_references type="UNIPROTKB">R4P168</external_references>
                </sequence>
                <ec_number>1.5.5.-</ec_number>
            </protein_or_peptide>
            <protein_or_peptide macromolecule_id="4">
                <name>Ferredoxin-like protein</name>
                <natural_source database="NCBI">
                    <organism ncbi="243274">Thermotoga maritima (strain ATCC 43589 / MSB8 / DSM 3109 / JCM 10099)</organism>
                    <strain>ATCC 43589 / MSB8 / DSM 3109 / JCM 10099</strain>
                </natural_source>
                <molecular_weight>
                    <theoretical units="MDa">0.010730219999999999</theoretical>
                </molecular_weight>
                <number_of_copies>2</number_of_copies>
                <recombinant_expression database="NCBI">
                    <recombinant_organism ncbi="1185654">Pyrococcus furiosus COM1</recombinant_organism>
                </recombinant_expression>
                <enantiomer>LEVO</enantiomer>
                <sequence>
                    <string>MRIEDKLYLNRYRTDEENPHLKIKDESICAEKCSDRPCVSCCPADVYEWTESGMEVKFEGCLECGTCRIVCPFGNIEWNY
PRGNYGVLYKFG</string>
                    <external_references type="UNIPROTKB">R4NRM2</external_references>
                </sequence>
            </protein_or_peptide>
            <ligand macromolecule_id="5">
                <name>FLAVIN-ADENINE DINUCLEOTIDE</name>
                <molecular_weight>
                    <theoretical units="MDa">0.0007855499999999999</theoretical>
                </molecular_weight>
                <number_of_copies>6</number_of_copies>
                <formula>FAD</formula>
            </ligand>
            <ligand macromolecule_id="6">
                <name>MENAQUINONE-7</name>
                <molecular_weight>
                    <theoretical units="MDa">0.000648999</theoretical>
                </molecular_weight>
                <number_of_copies>2</number_of_copies>
                <formula>MQ7</formula>
            </ligand>
            <ligand macromolecule_id="7">
                <name>IRON/SULFUR CLUSTER</name>
                <molecular_weight>
                    <theoretical units="MDa">0.00035163999999999996</theoretical>
                </molecular_weight>
                <number_of_copies>4</number_of_copies>
                <formula>SF4</formula>
            </ligand>
        </macromolecule_list>
    </sample>
    <structure_determination_list>
        <structure_determination structure_determination_id="1">
            <method>singleParticle</method>
            <aggregation_state>particle</aggregation_state>
            <specimen_preparation_list>
                <single_particle_preparation preparation_id="1">
                    <concentration units="mg/mL">0.3</concentration>
                    <buffer>
                        <ph>8.0</ph>
                        <component>
                            <concentration units="mM">20.0</concentration>
                            <formula>Tris-HCl</formula>
                            <name>Tris</name>
                        </component>
                        <component>
                            <concentration units="mM">200.0</concentration>
                            <formula>NaCl</formula>
                            <name>Sodium Chloride</name>
                        </component>
                        <component>
                            <concentration units="mM">2.0</concentration>
                            <formula>DTT</formula>
                            <name>Dithiothreitol</name>
                        </component>
                    </buffer>
                    <grid>
                        <model>Quantifoil R2/1</model>
                        <material>GOLD</material>
                    </grid>
                    <vitrification>
                        <cryogen_name>ETHANE</cryogen_name>
                        <chamber_humidity units="percentage">95</chamber_humidity>
                        <chamber_temperature units="K">284</chamber_temperature>
                        <instrument>FEI VITROBOT MARK III</instrument>
                    </vitrification>
                </single_particle_preparation>
            </specimen_preparation_list>
            <microscopy_list>
                <single_particle_microscopy microscopy_id="1">
                    <microscope>FEI TITAN KRIOS</microscope>
                    <illumination_mode>FLOOD BEAM</illumination_mode>
                    <imaging_mode>BRIGHT FIELD</imaging_mode>
                    <electron_source>FIELD EMISSION GUN</electron_source>
                    <acceleration_voltage units="kV">300</acceleration_voltage>
                    <image_recording_list>
                        <image_recording image_recording_id="1">
                            <film_or_detector_model>GATAN K2 SUMMIT (4k x 4k)</film_or_detector_model>
                            <detector_mode>SUPER-RESOLUTION</detector_mode>
                            <digitization_details/>
                            <number_grids_imaged>1</number_grids_imaged>
                            <number_real_images>9096</number_real_images>
                            <average_electron_dose_per_image units="e/Å^2">80.0</average_electron_dose_per_image>
                        </image_recording>
                    </image_recording_list>
                </single_particle_microscopy>
            </microscopy_list>
            <singleparticle_processing image_processing_id="1">
                <image_recording_id>1</image_recording_id>
                <particle_selection>
                    <number_selected>2471763</number_selected>
                </particle_selection>
                <ctf_correction>
                    <type>NONE</type>
                </ctf_correction>
                <startup_model type_of_model="NONE"/>
                <final_reconstruction>
                    <number_classes_used>1</number_classes_used>
                    <applied_symmetry>
                        <point_group>C2</point_group>
                    </applied_symmetry>
                    <algorithm>FOURIER SPACE</algorithm>
                    <resolution units="Å" res_type="BY AUTHOR">2.9</resolution>
                    <resolution_method>FSC 0.143 CUT-OFF</resolution_method>
                    <software_list>
                        <software>
                            <name>RELION</name>
                            <version>3.0</version>
                        </software>
                    </software_list>
                    <number_images_used>285377</number_images_used>
                </final_reconstruction>
                <initial_angle_assignment>
                    <type>MAXIMUM LIKELIHOOD</type>
                    <software_list>
                        <software>
                            <name>cryoSPARC</name>
                            <version>2.0</version>
                        </software>
                    </software_list>
                </initial_angle_assignment>
                <final_angle_assignment>
                    <type>MAXIMUM LIKELIHOOD</type>
                    <software_list>
                        <software>
                            <name>RELION</name>
                            <version>3.0</version>
                        </software>
                    </software_list>
                </final_angle_assignment>
                <final_three_d_classification>
                    <number_classes>5</number_classes>
                    <software_list>
                        <software>
                            <name>RELION</name>
                            <version>3.0</version>
                        </software>
                    </software_list>
                </final_three_d_classification>
            </singleparticle_processing>
        </structure_determination>
    </structure_determination_list>
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        <file>emd_22973.map.gz</file>
        <symmetry>
            <space_group>1</space_group>
        </symmetry>
        <data_type>IMAGE STORED AS FLOATING POINT NUMBER (4 BYTES)</data_type>
        <dimensions>
            <col>320</col>
            <row>320</row>
            <sec>320</sec>
        </dimensions>
        <origin>
            <col>0</col>
            <row>0</row>
            <sec>0</sec>
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        <spacing>
            <x>320</x>
            <y>320</y>
            <z>320</z>
        </spacing>
        <cell>
            <a units="Å">329.28003</a>
            <b units="Å">329.28003</b>
            <c units="Å">329.28003</c>
            <alpha units="deg">90.0</alpha>
            <beta units="deg">90.0</beta>
            <gamma units="deg">90.0</gamma>
        </cell>
        <axis_order>
            <fast>X</fast>
            <medium>Y</medium>
            <slow>Z</slow>
        </axis_order>
        <statistics>
            <minimum>-0.15086962</minimum>
            <maximum>0.26641878</maximum>
            <average>0.00009795881</average>
            <std>0.0038971945</std>
        </statistics>
        <pixel_spacing>
            <x units="Å">1.029</x>
            <y units="Å">1.029</y>
            <z units="Å">1.029</z>
        </pixel_spacing>
        <contour_list>
            <contour primary="true">
                <level>0.015</level>
                <source>AUTHOR</source>
            </contour>
        </contour_list>
        <label>::::EMDATABANK.org::::EMD-22973::::</label>
        <annotation_details>Electron bifurcating flavoprotein Fix/EtfABCX</annotation_details>
    </map>
    <interpretation>
        <modelling_list>
            <modelling>
                <refinement_protocol>RIGID BODY FIT</refinement_protocol>
            </modelling>
        </modelling_list>
        <segmentation_list>
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                <file>emd_22973_msk_1.map</file>
            </segmentation>
        </segmentation_list>
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