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Structure, dynamics and function of replisomal Protein complex

Conference Paper


Abstract


  • Knowledge of the structure of a protein can be very informative in determining its function, however, a

    structure alone does not tell the whole story. In the case of large, dynamic multi-protein systems where

    a coordinated network of interactions and enzymatic functions are involved, structural and biochemical

    information may be gainfully combined with knowledge of dynamics [1]. One such system is the

    bacterial replisome, which consists of more than a dozen interacting proteins and is capable of rapid

    DNA replication. As such, it is a good model system and a ripe target for antibiotic development. We

    have focussed on an interaction that involves one of the key organisational centres of the Gram-positive

    bacterial replisome, the DnaB helicase and its loading partner, DnaI, which together form a tight 6:6

    complex prior to loading of the hexameric helicase onto DNA, after which DnaI dissociates [2]. We have

    separately measured the dynamics of DnaI, DnaB and their complex using elastic, quasielastic and

    inelastic neutron scattering on IN6 at ILL (Grenoble, France).

    These measurements have established that the molecular fl exibility and diffusive motions are

    signifi cantly decreased when DnaI and DnaB are complexed, with DnaB having the greatest fl exibility

    when free. Further to this, complexation results in an increase in structural rigidity with the DnaB-DnaI

    complex having a signifi cantly higher effective force constant both above and below the temperature of

    dynamical transition. The vibrational density of states was also extracted, revealing that the DnaI-DnaB

    complex has less inelastic vibrational modes than DnaB and DnaI below the absolute value of 20 meV.

    [1] M. Tehei, A. Frölich, F. Gabel, M. Jasnin, U. Lehnert, D. Oesterhelt, A. M. Stadler, M. Weik, K. Wood and G.

    Zaccai, Faraday Discuss., 141, 117 (2009)

    [2] K. V. Loscha, K. Jaudzems, C. Ioannou, X. C. Su, F. R. Hill, G. Otting, N. E. Dixon and E. Liepinsh, Nucleic

    Acids Res., 37, 2395 (2009)

Authors


Publication Date


  • 2010

Citation


  • Hill, F. R., Ioannou, C., Koza, M., Dixon, N. E. & Tehei, M. (2010). Structure, dynamics and function of replisomal Protein complex. 9th AINSE / ANBUG Neutron Scattering Symposium: AANSS 2010 (pp. 23-23). AINSE.

Ro Metadata Url


  • http://ro.uow.edu.au/smhpapers/483

Start Page


  • 23

End Page


  • 23

Place Of Publication


  • http://www.ainse.edu.au/__data/assets/pdf_file/0005/49181/AANSS2010.pdf

Abstract


  • Knowledge of the structure of a protein can be very informative in determining its function, however, a

    structure alone does not tell the whole story. In the case of large, dynamic multi-protein systems where

    a coordinated network of interactions and enzymatic functions are involved, structural and biochemical

    information may be gainfully combined with knowledge of dynamics [1]. One such system is the

    bacterial replisome, which consists of more than a dozen interacting proteins and is capable of rapid

    DNA replication. As such, it is a good model system and a ripe target for antibiotic development. We

    have focussed on an interaction that involves one of the key organisational centres of the Gram-positive

    bacterial replisome, the DnaB helicase and its loading partner, DnaI, which together form a tight 6:6

    complex prior to loading of the hexameric helicase onto DNA, after which DnaI dissociates [2]. We have

    separately measured the dynamics of DnaI, DnaB and their complex using elastic, quasielastic and

    inelastic neutron scattering on IN6 at ILL (Grenoble, France).

    These measurements have established that the molecular fl exibility and diffusive motions are

    signifi cantly decreased when DnaI and DnaB are complexed, with DnaB having the greatest fl exibility

    when free. Further to this, complexation results in an increase in structural rigidity with the DnaB-DnaI

    complex having a signifi cantly higher effective force constant both above and below the temperature of

    dynamical transition. The vibrational density of states was also extracted, revealing that the DnaI-DnaB

    complex has less inelastic vibrational modes than DnaB and DnaI below the absolute value of 20 meV.

    [1] M. Tehei, A. Frölich, F. Gabel, M. Jasnin, U. Lehnert, D. Oesterhelt, A. M. Stadler, M. Weik, K. Wood and G.

    Zaccai, Faraday Discuss., 141, 117 (2009)

    [2] K. V. Loscha, K. Jaudzems, C. Ioannou, X. C. Su, F. R. Hill, G. Otting, N. E. Dixon and E. Liepinsh, Nucleic

    Acids Res., 37, 2395 (2009)

Authors


Publication Date


  • 2010

Citation


  • Hill, F. R., Ioannou, C., Koza, M., Dixon, N. E. & Tehei, M. (2010). Structure, dynamics and function of replisomal Protein complex. 9th AINSE / ANBUG Neutron Scattering Symposium: AANSS 2010 (pp. 23-23). AINSE.

Ro Metadata Url


  • http://ro.uow.edu.au/smhpapers/483

Start Page


  • 23

End Page


  • 23

Place Of Publication


  • http://www.ainse.edu.au/__data/assets/pdf_file/0005/49181/AANSS2010.pdf