Nanostructural determination of a lipid bilayer tethered to a gold substrate.
Identifieur interne : 004028 ( Ncbi/Merge ); précédent : 004027; suivant : 004029Nanostructural determination of a lipid bilayer tethered to a gold substrate.
Auteurs : Marco Maccarini [France] ; Erik B. Watkins [États-Unis] ; Barry Stidder [France] ; Jean-Pierre Alcaraz [France] ; Bruce A. Cornell [Australie] ; Donald K. Martin [France]Source :
- The European physical journal. E, Soft matter [ 1292-895X ] ; 2016.
Abstract
Tethered lipid bilayer membranes (tBLM) are planar membranes composed of free lipids and molecules tethered to a solid planar substrate providing a useful model of biological membranes for a wide range of biophysical studies and biotechnological applications. The properties of the tBLM depend on the free lipids and on the chemistry of the tethering molecules. We present a nanoscale characterization of a tBLM composed of deuterated 1,2-dimyristoyl-sn-glycero-3-phosphocholine (d-DMPC) free lipids, benzyl disulfide undecaethylene glycol phytanol (DLP) tethering molecules, and benzyl disulfiide tetraethylene glycol polar spacer molecules (PSM) used to control the areal density of tethering molecules through coadsorption. The use of selected isotopic substitution provides a way to distinguish the conformation and location of the tethered lipids from the free lipids and to elucidate how the two components influence the structure of the tBLM. These findings provide useful information to optimise the insertion of transmembrane proteins into the tethered bilayer system.
DOI: 10.1140/epje/i2016-16123-5
PubMed: 27966072
Links toward previous steps (curation, corpus...)
- to stream PubMed, to step Corpus: 001414
- to stream PubMed, to step Curation: 001392
- to stream PubMed, to step Checkpoint: 001392
Links to Exploration step
pubmed:27966072Le document en format XML
<record><TEI><teiHeader><fileDesc><titleStmt><title xml:lang="en">Nanostructural determination of a lipid bilayer tethered to a gold substrate.</title><author><name sortKey="Maccarini, Marco" sort="Maccarini, Marco" uniqKey="Maccarini M" first="Marco" last="Maccarini">Marco Maccarini</name><affiliation wicri:level="4"><nlm:affiliation>TIMC/IMAG, Université Grenoble Alpes, (UMR 5525), Grenoble, France. marco.maccarini@imag.fr.</nlm:affiliation><country xml:lang="fr">France</country><wicri:regionArea>TIMC/IMAG, Université Grenoble Alpes, (UMR 5525), Grenoble</wicri:regionArea><placeName><region type="region">Auvergne-Rhône-Alpes</region><region type="old region">Rhône-Alpes</region><settlement type="city">Grenoble</settlement><settlement type="city">Grenoble</settlement></placeName><orgName type="university">Université Grenoble-Alpes</orgName></affiliation></author><author><name sortKey="Watkins, Erik B" sort="Watkins, Erik B" uniqKey="Watkins E" first="Erik B" last="Watkins">Erik B. Watkins</name><affiliation wicri:level="2"><nlm:affiliation>Los Alamos National Laboratory, 87545, Los Alamos, NM, USA.</nlm:affiliation><country xml:lang="fr">États-Unis</country><wicri:regionArea>Los Alamos National Laboratory, 87545, Los Alamos, NM</wicri:regionArea><placeName><region type="state">Nouveau-Mexique</region></placeName></affiliation></author><author><name sortKey="Stidder, Barry" sort="Stidder, Barry" uniqKey="Stidder B" first="Barry" last="Stidder">Barry Stidder</name><affiliation wicri:level="4"><nlm:affiliation>TIMC/IMAG, Université Grenoble Alpes, (UMR 5525), Grenoble, France.</nlm:affiliation><country xml:lang="fr">France</country><wicri:regionArea>TIMC/IMAG, Université Grenoble Alpes, (UMR 5525), Grenoble</wicri:regionArea><placeName><region type="region">Auvergne-Rhône-Alpes</region><region type="old region">Rhône-Alpes</region><settlement type="city">Grenoble</settlement><settlement type="city">Grenoble</settlement></placeName><orgName type="university">Université Grenoble-Alpes</orgName></affiliation></author><author><name sortKey="Alcaraz, Jean Pierre" sort="Alcaraz, Jean Pierre" uniqKey="Alcaraz J" first="Jean-Pierre" last="Alcaraz">Jean-Pierre Alcaraz</name><affiliation wicri:level="4"><nlm:affiliation>TIMC/IMAG, Université Grenoble Alpes, (UMR 5525), Grenoble, France.</nlm:affiliation><country xml:lang="fr">France</country><wicri:regionArea>TIMC/IMAG, Université Grenoble Alpes, (UMR 5525), Grenoble</wicri:regionArea><placeName><region type="region">Auvergne-Rhône-Alpes</region><region type="old region">Rhône-Alpes</region><settlement type="city">Grenoble</settlement><settlement type="city">Grenoble</settlement></placeName><orgName type="university">Université Grenoble-Alpes</orgName></affiliation></author><author><name sortKey="Cornell, Bruce A" sort="Cornell, Bruce A" uniqKey="Cornell B" first="Bruce A" last="Cornell">Bruce A. Cornell</name><affiliation wicri:level="1"><nlm:affiliation>SDx Tethered Membranes Pty Ltd u6 30-32, Barcoo Street, 2069, Roseville, NSW, Australia.</nlm:affiliation><country xml:lang="fr">Australie</country><wicri:regionArea>SDx Tethered Membranes Pty Ltd u6 30-32, Barcoo Street, 2069, Roseville, NSW</wicri:regionArea><wicri:noRegion>NSW</wicri:noRegion></affiliation></author><author><name sortKey="Martin, Donald K" sort="Martin, Donald K" uniqKey="Martin D" first="Donald K" last="Martin">Donald K. Martin</name><affiliation wicri:level="4"><nlm:affiliation>TIMC/IMAG, Université Grenoble Alpes, (UMR 5525), Grenoble, France.</nlm:affiliation><country xml:lang="fr">France</country><wicri:regionArea>TIMC/IMAG, Université Grenoble Alpes, (UMR 5525), Grenoble</wicri:regionArea><placeName><region type="region">Auvergne-Rhône-Alpes</region><region type="old region">Rhône-Alpes</region><settlement type="city">Grenoble</settlement><settlement type="city">Grenoble</settlement></placeName><orgName type="university">Université Grenoble-Alpes</orgName></affiliation></author></titleStmt><publicationStmt><idno type="wicri:source">PubMed</idno><date when="2016">2016</date><idno type="RBID">pubmed:27966072</idno><idno type="pmid">27966072</idno><idno type="doi">10.1140/epje/i2016-16123-5</idno><idno type="wicri:Area/PubMed/Corpus">001414</idno><idno type="wicri:explorRef" wicri:stream="PubMed" wicri:step="Corpus" wicri:corpus="PubMed">001414</idno><idno type="wicri:Area/PubMed/Curation">001392</idno><idno type="wicri:explorRef" wicri:stream="PubMed" wicri:step="Curation">001392</idno><idno type="wicri:Area/PubMed/Checkpoint">001392</idno><idno type="wicri:explorRef" wicri:stream="Checkpoint" wicri:step="PubMed">001392</idno><idno type="wicri:Area/Ncbi/Merge">004028</idno></publicationStmt><sourceDesc><biblStruct><analytic><title xml:lang="en">Nanostructural determination of a lipid bilayer tethered to a gold substrate.</title><author><name sortKey="Maccarini, Marco" sort="Maccarini, Marco" uniqKey="Maccarini M" first="Marco" last="Maccarini">Marco Maccarini</name><affiliation wicri:level="4"><nlm:affiliation>TIMC/IMAG, Université Grenoble Alpes, (UMR 5525), Grenoble, France. marco.maccarini@imag.fr.</nlm:affiliation><country xml:lang="fr">France</country><wicri:regionArea>TIMC/IMAG, Université Grenoble Alpes, (UMR 5525), Grenoble</wicri:regionArea><placeName><region type="region">Auvergne-Rhône-Alpes</region><region type="old region">Rhône-Alpes</region><settlement type="city">Grenoble</settlement><settlement type="city">Grenoble</settlement></placeName><orgName type="university">Université Grenoble-Alpes</orgName></affiliation></author><author><name sortKey="Watkins, Erik B" sort="Watkins, Erik B" uniqKey="Watkins E" first="Erik B" last="Watkins">Erik B. Watkins</name><affiliation wicri:level="2"><nlm:affiliation>Los Alamos National Laboratory, 87545, Los Alamos, NM, USA.</nlm:affiliation><country xml:lang="fr">États-Unis</country><wicri:regionArea>Los Alamos National Laboratory, 87545, Los Alamos, NM</wicri:regionArea><placeName><region type="state">Nouveau-Mexique</region></placeName></affiliation></author><author><name sortKey="Stidder, Barry" sort="Stidder, Barry" uniqKey="Stidder B" first="Barry" last="Stidder">Barry Stidder</name><affiliation wicri:level="4"><nlm:affiliation>TIMC/IMAG, Université Grenoble Alpes, (UMR 5525), Grenoble, France.</nlm:affiliation><country xml:lang="fr">France</country><wicri:regionArea>TIMC/IMAG, Université Grenoble Alpes, (UMR 5525), Grenoble</wicri:regionArea><placeName><region type="region">Auvergne-Rhône-Alpes</region><region type="old region">Rhône-Alpes</region><settlement type="city">Grenoble</settlement><settlement type="city">Grenoble</settlement></placeName><orgName type="university">Université Grenoble-Alpes</orgName></affiliation></author><author><name sortKey="Alcaraz, Jean Pierre" sort="Alcaraz, Jean Pierre" uniqKey="Alcaraz J" first="Jean-Pierre" last="Alcaraz">Jean-Pierre Alcaraz</name><affiliation wicri:level="4"><nlm:affiliation>TIMC/IMAG, Université Grenoble Alpes, (UMR 5525), Grenoble, France.</nlm:affiliation><country xml:lang="fr">France</country><wicri:regionArea>TIMC/IMAG, Université Grenoble Alpes, (UMR 5525), Grenoble</wicri:regionArea><placeName><region type="region">Auvergne-Rhône-Alpes</region><region type="old region">Rhône-Alpes</region><settlement type="city">Grenoble</settlement><settlement type="city">Grenoble</settlement></placeName><orgName type="university">Université Grenoble-Alpes</orgName></affiliation></author><author><name sortKey="Cornell, Bruce A" sort="Cornell, Bruce A" uniqKey="Cornell B" first="Bruce A" last="Cornell">Bruce A. Cornell</name><affiliation wicri:level="1"><nlm:affiliation>SDx Tethered Membranes Pty Ltd u6 30-32, Barcoo Street, 2069, Roseville, NSW, Australia.</nlm:affiliation><country xml:lang="fr">Australie</country><wicri:regionArea>SDx Tethered Membranes Pty Ltd u6 30-32, Barcoo Street, 2069, Roseville, NSW</wicri:regionArea><wicri:noRegion>NSW</wicri:noRegion></affiliation></author><author><name sortKey="Martin, Donald K" sort="Martin, Donald K" uniqKey="Martin D" first="Donald K" last="Martin">Donald K. Martin</name><affiliation wicri:level="4"><nlm:affiliation>TIMC/IMAG, Université Grenoble Alpes, (UMR 5525), Grenoble, France.</nlm:affiliation><country xml:lang="fr">France</country><wicri:regionArea>TIMC/IMAG, Université Grenoble Alpes, (UMR 5525), Grenoble</wicri:regionArea><placeName><region type="region">Auvergne-Rhône-Alpes</region><region type="old region">Rhône-Alpes</region><settlement type="city">Grenoble</settlement><settlement type="city">Grenoble</settlement></placeName><orgName type="university">Université Grenoble-Alpes</orgName></affiliation></author></analytic><series><title level="j">The European physical journal. E, Soft matter</title><idno type="eISSN">1292-895X</idno><imprint><date when="2016" type="published">2016</date></imprint></series></biblStruct></sourceDesc></fileDesc><profileDesc><textClass></textClass></profileDesc></teiHeader><front><div type="abstract" xml:lang="en">Tethered lipid bilayer membranes (tBLM) are planar membranes composed of free lipids and molecules tethered to a solid planar substrate providing a useful model of biological membranes for a wide range of biophysical studies and biotechnological applications. The properties of the tBLM depend on the free lipids and on the chemistry of the tethering molecules. We present a nanoscale characterization of a tBLM composed of deuterated 1,2-dimyristoyl-sn-glycero-3-phosphocholine (d-DMPC) free lipids, benzyl disulfide undecaethylene glycol phytanol (DLP) tethering molecules, and benzyl disulfiide tetraethylene glycol polar spacer molecules (PSM) used to control the areal density of tethering molecules through coadsorption. The use of selected isotopic substitution provides a way to distinguish the conformation and location of the tethered lipids from the free lipids and to elucidate how the two components influence the structure of the tBLM. These findings provide useful information to optimise the insertion of transmembrane proteins into the tethered bilayer system.</div></front></TEI><pubmed><MedlineCitation Status="In-Process" Owner="NLM"><PMID Version="1">27966072</PMID><DateCreated><Year>2016</Year><Month>12</Month><Day>14</Day></DateCreated><DateRevised><Year>2017</Year><Month>10</Month><Day>14</Day></DateRevised><Article PubModel="Print-Electronic"><Journal><ISSN IssnType="Electronic">1292-895X</ISSN><JournalIssue CitedMedium="Internet"><Volume>39</Volume><Issue>12</Issue><PubDate><Year>2016</Year><Month>Dec</Month></PubDate></JournalIssue><Title>The European physical journal. E, Soft matter</Title><ISOAbbreviation>Eur Phys J E Soft Matter</ISOAbbreviation></Journal><ArticleTitle>Nanostructural determination of a lipid bilayer tethered to a gold substrate.</ArticleTitle><Pagination><MedlinePgn>123</MedlinePgn></Pagination><Abstract><AbstractText>Tethered lipid bilayer membranes (tBLM) are planar membranes composed of free lipids and molecules tethered to a solid planar substrate providing a useful model of biological membranes for a wide range of biophysical studies and biotechnological applications. The properties of the tBLM depend on the free lipids and on the chemistry of the tethering molecules. We present a nanoscale characterization of a tBLM composed of deuterated 1,2-dimyristoyl-sn-glycero-3-phosphocholine (d-DMPC) free lipids, benzyl disulfide undecaethylene glycol phytanol (DLP) tethering molecules, and benzyl disulfiide tetraethylene glycol polar spacer molecules (PSM) used to control the areal density of tethering molecules through coadsorption. The use of selected isotopic substitution provides a way to distinguish the conformation and location of the tethered lipids from the free lipids and to elucidate how the two components influence the structure of the tBLM. These findings provide useful information to optimise the insertion of transmembrane proteins into the tethered bilayer system.</AbstractText></Abstract><AuthorList CompleteYN="Y"><Author ValidYN="Y"><LastName>Maccarini</LastName><ForeName>Marco</ForeName><Initials>M</Initials><AffiliationInfo><Affiliation>TIMC/IMAG, Université Grenoble Alpes, (UMR 5525), Grenoble, France. marco.maccarini@imag.fr.</Affiliation></AffiliationInfo></Author><Author ValidYN="Y"><LastName>Watkins</LastName><ForeName>Erik B</ForeName><Initials>EB</Initials><AffiliationInfo><Affiliation>Los Alamos National Laboratory, 87545, Los Alamos, NM, USA.</Affiliation></AffiliationInfo></Author><Author ValidYN="Y"><LastName>Stidder</LastName><ForeName>Barry</ForeName><Initials>B</Initials><AffiliationInfo><Affiliation>TIMC/IMAG, Université Grenoble Alpes, (UMR 5525), Grenoble, France.</Affiliation></AffiliationInfo></Author><Author ValidYN="Y"><LastName>Alcaraz</LastName><ForeName>Jean-Pierre</ForeName><Initials>JP</Initials><AffiliationInfo><Affiliation>TIMC/IMAG, Université Grenoble Alpes, (UMR 5525), Grenoble, France.</Affiliation></AffiliationInfo></Author><Author ValidYN="Y"><LastName>Cornell</LastName><ForeName>Bruce A</ForeName><Initials>BA</Initials><AffiliationInfo><Affiliation>SDx Tethered Membranes Pty Ltd u6 30-32, Barcoo Street, 2069, Roseville, NSW, Australia.</Affiliation></AffiliationInfo></Author><Author ValidYN="Y"><LastName>Martin</LastName><ForeName>Donald K</ForeName><Initials>DK</Initials><AffiliationInfo><Affiliation>TIMC/IMAG, Université Grenoble Alpes, (UMR 5525), Grenoble, France.</Affiliation></AffiliationInfo></Author></AuthorList><Language>eng</Language><PublicationTypeList><PublicationType UI="D016428">Journal Article</PublicationType></PublicationTypeList><ArticleDate DateType="Electronic"><Year>2016</Year><Month>12</Month><Day>15</Day></ArticleDate></Article><MedlineJournalInfo><Country>France</Country><MedlineTA>Eur Phys J E Soft Matter</MedlineTA><NlmUniqueID>101126530</NlmUniqueID><ISSNLinking>1292-8941</ISSNLinking></MedlineJournalInfo><CommentsCorrectionsList><CommentsCorrections RefType="Cites"><RefSource>Biophys J. 1998 Aug;75(2):734-44</RefSource><PMID Version="1">9675175</PMID></CommentsCorrections><CommentsCorrections RefType="Cites"><RefSource>Biophys J. 1994 Sep;67(3):1126-33</RefSource><PMID Version="1">7811924</PMID></CommentsCorrections><CommentsCorrections RefType="Cites"><RefSource>Proc Natl Acad Sci U S A. 2008 Feb 26;105(8):2848-52</RefSource><PMID Version="1">18287056</PMID></CommentsCorrections><CommentsCorrections RefType="Cites"><RefSource>J Biol Chem. 1979 Jul 10;254(13):6068-78</RefSource><PMID Version="1">447695</PMID></CommentsCorrections><CommentsCorrections RefType="Cites"><RefSource>Biophys J. 2002 Dec;83(6):3324-35</RefSource><PMID Version="1">12496100</PMID></CommentsCorrections><CommentsCorrections RefType="Cites"><RefSource>Biophys J. 1991 Feb;59(2):289-94</RefSource><PMID Version="1">2009353</PMID></CommentsCorrections><CommentsCorrections RefType="Cites"><RefSource>Biointerphases. 2007 Mar;2(1):21-33</RefSource><PMID Version="1">20408633</PMID></CommentsCorrections><CommentsCorrections RefType="Cites"><RefSource>Langmuir. 2013 Jul 9;29(27):8645-56</RefSource><PMID Version="1">23745652</PMID></CommentsCorrections><CommentsCorrections RefType="Cites"><RefSource>Nature. 1997 Jun 5;387(6633):580-3</RefSource><PMID Version="1">9177344</PMID></CommentsCorrections><CommentsCorrections RefType="Cites"><RefSource>Biochim Biophys Acta. 2000 Nov 10;1469(3):159-95</RefSource><PMID Version="1">11063882</PMID></CommentsCorrections><CommentsCorrections RefType="Cites"><RefSource>Langmuir. 2014 Aug 12;30(31):9442-7</RefSource><PMID Version="1">25046694</PMID></CommentsCorrections><CommentsCorrections RefType="Cites"><RefSource>Langmuir. 2009 Apr 7;25(7):4219-29</RefSource><PMID Version="1">19714901</PMID></CommentsCorrections><CommentsCorrections RefType="Cites"><RefSource>Langmuir. 2010 Feb 16;26(4):2609-17</RefSource><PMID Version="1">20085365</PMID></CommentsCorrections><CommentsCorrections RefType="Cites"><RefSource>Biophys J. 1992 Apr;61(4):1025-35</RefSource><PMID Version="1">19431823</PMID></CommentsCorrections><CommentsCorrections RefType="Cites"><RefSource>Soft Matter. 2015 Feb 7;11(5):918-26</RefSource><PMID Version="1">25503248</PMID></CommentsCorrections><CommentsCorrections RefType="Cites"><RefSource>Langmuir. 2006 Jun 6;22(12):5509-19</RefSource><PMID Version="1">16732685</PMID></CommentsCorrections><CommentsCorrections RefType="Cites"><RefSource>Langmuir. 2011 Nov 15;27(22):13618-28</RefSource><PMID Version="1">21728300</PMID></CommentsCorrections><CommentsCorrections RefType="Cites"><RefSource>Phys Rev E Stat Nonlin Soft Matter Phys. 2011 Jun;83(6 Pt 1):061918</RefSource><PMID Version="1">21797414</PMID></CommentsCorrections><CommentsCorrections RefType="Cites"><RefSource>Langmuir. 2013 Jun 4;29(22):6606-14</RefSource><PMID Version="1">23638939</PMID></CommentsCorrections></CommentsCorrectionsList><KeywordList Owner="NOTNLM"><Keyword MajorTopicYN="N">Living systems: Biomimetic Systems</Keyword></KeywordList></MedlineCitation><PubmedData><History><PubMedPubDate PubStatus="received"><Year>2016</Year><Month>08</Month><Day>03</Day></PubMedPubDate><PubMedPubDate PubStatus="accepted"><Year>2016</Year><Month>11</Month><Day>23</Day></PubMedPubDate><PubMedPubDate PubStatus="entrez"><Year>2016</Year><Month>12</Month><Day>15</Day><Hour>6</Hour><Minute>0</Minute></PubMedPubDate><PubMedPubDate PubStatus="pubmed"><Year>2016</Year><Month>12</Month><Day>15</Day><Hour>6</Hour><Minute>0</Minute></PubMedPubDate><PubMedPubDate PubStatus="medline"><Year>2016</Year><Month>12</Month><Day>15</Day><Hour>6</Hour><Minute>0</Minute></PubMedPubDate></History><PublicationStatus>ppublish</PublicationStatus><ArticleIdList><ArticleId IdType="pubmed">27966072</ArticleId><ArticleId IdType="doi">10.1140/epje/i2016-16123-5</ArticleId><ArticleId IdType="pii">10.1140/epje/i2016-16123-5</ArticleId></ArticleIdList></PubmedData></pubmed><affiliations><list><country><li>Australie</li><li>France</li><li>États-Unis</li></country><region><li>Auvergne-Rhône-Alpes</li><li>Nouveau-Mexique</li><li>Rhône-Alpes</li></region><settlement><li>Grenoble</li></settlement><orgName><li>Université Grenoble-Alpes</li></orgName></list><tree><country name="France"><region name="Auvergne-Rhône-Alpes"><name sortKey="Maccarini, Marco" sort="Maccarini, Marco" uniqKey="Maccarini M" first="Marco" last="Maccarini">Marco Maccarini</name></region><name sortKey="Alcaraz, Jean Pierre" sort="Alcaraz, Jean Pierre" uniqKey="Alcaraz J" first="Jean-Pierre" last="Alcaraz">Jean-Pierre Alcaraz</name><name sortKey="Martin, Donald K" sort="Martin, Donald K" uniqKey="Martin D" first="Donald K" last="Martin">Donald K. Martin</name><name sortKey="Stidder, Barry" sort="Stidder, Barry" uniqKey="Stidder B" first="Barry" last="Stidder">Barry Stidder</name></country><country name="États-Unis"><region name="Nouveau-Mexique"><name sortKey="Watkins, Erik B" sort="Watkins, Erik B" uniqKey="Watkins E" first="Erik B" last="Watkins">Erik B. Watkins</name></region></country><country name="Australie"><noRegion><name sortKey="Cornell, Bruce A" sort="Cornell, Bruce A" uniqKey="Cornell B" first="Bruce A" last="Cornell">Bruce A. Cornell</name></noRegion></country></tree></affiliations></record>Pour manipuler ce document sous Unix (Dilib)
EXPLOR_STEP=$WICRI_ROOT/Wicri/Asie/explor/AustralieFrV1/Data/Ncbi/Merge
HfdSelect -h $EXPLOR_STEP/biblio.hfd -nk 004028 | SxmlIndent | more
Ou
HfdSelect -h $EXPLOR_AREA/Data/Ncbi/Merge/biblio.hfd -nk 004028 | SxmlIndent | more
Pour mettre un lien sur cette page dans le réseau Wicri
{{Explor lien
|wiki= Wicri/Asie
|area= AustralieFrV1
|flux= Ncbi
|étape= Merge
|type= RBID
|clé= pubmed:27966072
|texte= Nanostructural determination of a lipid bilayer tethered to a gold substrate.
}}
Pour générer des pages wiki
HfdIndexSelect -h $EXPLOR_AREA/Data/Ncbi/Merge/RBID.i -Sk "pubmed:27966072" \
| HfdSelect -Kh $EXPLOR_AREA/Data/Ncbi/Merge/biblio.hfd \
| NlmPubMed2Wicri -a AustralieFrV1
| This area was generated with Dilib version V0.6.33. |  |