Probing the structure of F-actin: cross-links constrain atomic models and modify actin dynamics.
Identifieur interne : 003427 ( Main/Exploration ); précédent : 003426; suivant : 003428Probing the structure of F-actin: cross-links constrain atomic models and modify actin dynamics.
Auteurs : A. Orlova [États-Unis] ; V E Galkin ; M S Vanloock ; E. Kim ; A. Shvetsov ; E. Reisler ; E H EgelmanSource :
- Journal of molecular biology [ 0022-2836 ] ; 2001.
Descripteurs français
- KwdFr :
- Actines (), Actines (génétique), Actines (métabolisme), Algorithmes, Animaux, Conformation des protéines, Deoxyribonuclease I (métabolisme), Disulfures (), Levures (), Microscopie électronique, Modèles moléculaires, Modèles statistiques, Muscles squelettiques (), Mutation, Traitement d'image par ordinateur.
- MESH :
English descriptors
- KwdEn :
- Actins (chemistry), Actins (genetics), Actins (metabolism), Algorithms, Animals, Deoxyribonuclease I (metabolism), Disulfides (chemistry), Image Processing, Computer-Assisted, Microscopy, Electron, Models, Molecular, Models, Statistical, Muscle, Skeletal (chemistry), Mutation, Protein Conformation, Yeasts (chemistry).
- MESH :
- chemical , chemistry : Actins, Disulfides.
- chemical , genetics : Actins.
- chemical , metabolism : Actins, Deoxyribonuclease I.
- chemistry : Muscle, Skeletal, Yeasts.
- Algorithms, Animals, Image Processing, Computer-Assisted, Microscopy, Electron, Models, Molecular, Models, Statistical, Mutation, Protein Conformation.
Abstract
Cross-links between protomers in F-actin can be used as a very sensitive probe of both the dynamics and structure of F-actin. We have characterized filaments formed from a previously described yeast actin Q41C mutant, where disulfide bonds can be formed between the Cys41 that is introduced into subdomain-2 and Cys374 on an adjacent protomer. We find that the distribution of cross-linked n-mers shows no cooperativity and corresponds to a random probability cross-linking reaction. The random distribution suggests that disulfide formation does not cause a significant perturbation of the F-actin structure. Consistent with this lack of perturbation, three-dimensional reconstructions of extensively cross-linked filaments, using a new approach to helical image analysis, show very small structural changes with respect to uncross-linked filaments. This finding is in conflict with refined models but in agreement with the original Holmes et al. model for F-actin. Under conditions where 94 % of the protomers are linked by disulfide bonds, the distribution of filament twist becomes more heterogeneous with respect to control filaments. A molecular model suggests that strain, introduced by the disulfide, is relieved by increasing the twist of the long-pitch actin helices. Disulfide formation makes yeast actin filaments approximately three times less flexible in terms of bending and similar, in this respect, to vertebrate skeletal muscle F-actin. These observations support previous reports that the rigidity of F-actin can be controlled by the position of subdomain-2, and that this region is more flexible in yeast F-actin than in skeletal muscle F-actin.
DOI: 10.1006/jmbi.2001.4945
PubMed: 11545588
Affiliations:
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Le document en format XML
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Orlova</name><affiliation wicri:level="2"><nlm:affiliation>Department of Biochemistry and Molecular Genetics, University of Virginia Health Sciences Center, Charlottesville, VA 22908-0733, USA.</nlm:affiliation><country xml:lang="fr">États-Unis</country><wicri:regionArea>Department of Biochemistry and Molecular Genetics, University of Virginia Health Sciences Center, Charlottesville, VA 22908-0733</wicri:regionArea><placeName><region type="state">Virginie</region></placeName></affiliation></author><author><name sortKey="Galkin, V E" sort="Galkin, V E" uniqKey="Galkin V" first="V E" last="Galkin">V E Galkin</name></author><author><name sortKey="Vanloock, M S" sort="Vanloock, M S" uniqKey="Vanloock M" first="M S" last="Vanloock">M S Vanloock</name></author><author><name sortKey="Kim, E" sort="Kim, E" uniqKey="Kim E" first="E" last="Kim">E. Kim</name></author><author><name sortKey="Shvetsov, A" sort="Shvetsov, A" uniqKey="Shvetsov A" first="A" last="Shvetsov">A. Shvetsov</name></author><author><name sortKey="Reisler, E" sort="Reisler, E" uniqKey="Reisler E" first="E" last="Reisler">E. Reisler</name></author><author><name sortKey="Egelman, E H" sort="Egelman, E H" uniqKey="Egelman E" first="E H" last="Egelman">E H Egelman</name></author></analytic><series><title level="j">Journal of molecular biology</title><idno type="ISSN">0022-2836</idno><imprint><date when="2001" type="published">2001</date></imprint></series></biblStruct></sourceDesc></fileDesc><profileDesc><textClass><keywords scheme="KwdEn" xml:lang="en"><term>Actins (chemistry)</term><term>Actins (genetics)</term><term>Actins (metabolism)</term><term>Algorithms</term><term>Animals</term><term>Deoxyribonuclease I (metabolism)</term><term>Disulfides (chemistry)</term><term>Image Processing, Computer-Assisted</term><term>Microscopy, Electron</term><term>Models, Molecular</term><term>Models, Statistical</term><term>Muscle, Skeletal (chemistry)</term><term>Mutation</term><term>Protein Conformation</term><term>Yeasts (chemistry)</term></keywords><keywords scheme="KwdFr" xml:lang="fr"><term>Actines ()</term><term>Actines (génétique)</term><term>Actines (métabolisme)</term><term>Algorithmes</term><term>Animaux</term><term>Conformation des protéines</term><term>Deoxyribonuclease I (métabolisme)</term><term>Disulfures ()</term><term>Levures ()</term><term>Microscopie électronique</term><term>Modèles moléculaires</term><term>Modèles statistiques</term><term>Muscles squelettiques ()</term><term>Mutation</term><term>Traitement d'image par ordinateur</term></keywords><keywords scheme="MESH" type="chemical" qualifier="chemistry" xml:lang="en"><term>Actins</term><term>Disulfides</term></keywords><keywords scheme="MESH" type="chemical" qualifier="genetics" xml:lang="en"><term>Actins</term></keywords><keywords scheme="MESH" type="chemical" qualifier="metabolism" xml:lang="en"><term>Actins</term><term>Deoxyribonuclease I</term></keywords><keywords scheme="MESH" qualifier="chemistry" xml:lang="en"><term>Muscle, Skeletal</term><term>Yeasts</term></keywords><keywords scheme="MESH" qualifier="génétique" xml:lang="fr"><term>Actines</term></keywords><keywords scheme="MESH" qualifier="métabolisme" xml:lang="fr"><term>Actines</term><term>Deoxyribonuclease I</term></keywords><keywords scheme="MESH" xml:lang="en"><term>Algorithms</term><term>Animals</term><term>Image Processing, Computer-Assisted</term><term>Microscopy, Electron</term><term>Models, Molecular</term><term>Models, Statistical</term><term>Mutation</term><term>Protein Conformation</term></keywords><keywords scheme="MESH" xml:lang="fr"><term>Actines</term><term>Algorithmes</term><term>Animaux</term><term>Conformation des protéines</term><term>Disulfures</term><term>Levures</term><term>Microscopie électronique</term><term>Modèles moléculaires</term><term>Modèles statistiques</term><term>Muscles squelettiques</term><term>Mutation</term><term>Traitement d'image par ordinateur</term></keywords></textClass></profileDesc></teiHeader><front><div type="abstract" xml:lang="en">Cross-links between protomers in F-actin can be used as a very sensitive probe of both the dynamics and structure of F-actin. We have characterized filaments formed from a previously described yeast actin Q41C mutant, where disulfide bonds can be formed between the Cys41 that is introduced into subdomain-2 and Cys374 on an adjacent protomer. We find that the distribution of cross-linked n-mers shows no cooperativity and corresponds to a random probability cross-linking reaction. The random distribution suggests that disulfide formation does not cause a significant perturbation of the F-actin structure. Consistent with this lack of perturbation, three-dimensional reconstructions of extensively cross-linked filaments, using a new approach to helical image analysis, show very small structural changes with respect to uncross-linked filaments. This finding is in conflict with refined models but in agreement with the original Holmes et al. model for F-actin. Under conditions where 94 % of the protomers are linked by disulfide bonds, the distribution of filament twist becomes more heterogeneous with respect to control filaments. A molecular model suggests that strain, introduced by the disulfide, is relieved by increasing the twist of the long-pitch actin helices. Disulfide formation makes yeast actin filaments approximately three times less flexible in terms of bending and similar, in this respect, to vertebrate skeletal muscle F-actin. These observations support previous reports that the rigidity of F-actin can be controlled by the position of subdomain-2, and that this region is more flexible in yeast F-actin than in skeletal muscle F-actin.</div></front></TEI><affiliations><list><country><li>États-Unis</li></country><region><li>Virginie</li></region></list><tree><noCountry><name sortKey="Egelman, E H" sort="Egelman, E H" uniqKey="Egelman E" first="E H" last="Egelman">E H Egelman</name><name sortKey="Galkin, V E" sort="Galkin, V E" uniqKey="Galkin V" first="V E" last="Galkin">V E Galkin</name><name sortKey="Kim, E" sort="Kim, E" uniqKey="Kim E" first="E" last="Kim">E. Kim</name><name sortKey="Reisler, E" sort="Reisler, E" uniqKey="Reisler E" first="E" last="Reisler">E. Reisler</name><name sortKey="Shvetsov, A" sort="Shvetsov, A" uniqKey="Shvetsov A" first="A" last="Shvetsov">A. Shvetsov</name><name sortKey="Vanloock, M S" sort="Vanloock, M S" uniqKey="Vanloock M" first="M S" last="Vanloock">M S Vanloock</name></noCountry><country name="États-Unis"><region name="Virginie"><name sortKey="Orlova, A" sort="Orlova, A" uniqKey="Orlova A" first="A" last="Orlova">A. Orlova</name></region></country></tree></affiliations></record>Pour manipuler ce document sous Unix (Dilib)
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