The conformational space sampled by the two-domain protein calmodulin has been explored by an approach based on four sets of NMR observables obtained on Tb3+and Tm3+substituted proteins. The observables are the pseudocontact shifts and residual dipolar couplings of the C-terminal domain when lanthanide substitution is at the N-terminal domain. Each set of observables provides independent information on the conformations experienced by the molecule. It is found that not all sterically allowed conformations are equally populated. Taking the N-terminal domain as the reference, the C-terminal domain preferentially resides in a region of space inscribed in a wide elliptical cone. The axis of the cone is tilted by ≈30° with respect to the direction of the N-terminal part of the interdomain helix, which is known to have a flexible central part in solution. The C-terminal domain also undergoes rotation about the axis defined by the C-terminal part of the interdomain helix. Neither the extended helix conformation initially observed in the solid state for free calcium calmodulin nor the closed conformation(s) adopted by calcium calmodulin either alone or in its adduct(s) with target peptide(s) is among the most preferred ones. These findings are unique, both in terms of structural information obtained on a biomolecule that samples multiple conformations and in terms of the approach developed to achieve the results. The same approach is in principle applicable to other multidomain proteins, as well as to multiple interaction modes between two macromolecular partners.

Experimentally exploring the conformational space sampled by domain reorientation in calmodulin / Peana, Massimiliano Francesco; Zoroddu, Maria Antonietta. - 101:18(2004), pp. 6841-6846. [10.1073/pnas.0308641101]

Experimentally exploring the conformational space sampled by domain reorientation in calmodulin

Peana, Massimiliano Francesco;Zoroddu, Maria Antonietta;
2004

Abstract

The conformational space sampled by the two-domain protein calmodulin has been explored by an approach based on four sets of NMR observables obtained on Tb3+and Tm3+substituted proteins. The observables are the pseudocontact shifts and residual dipolar couplings of the C-terminal domain when lanthanide substitution is at the N-terminal domain. Each set of observables provides independent information on the conformations experienced by the molecule. It is found that not all sterically allowed conformations are equally populated. Taking the N-terminal domain as the reference, the C-terminal domain preferentially resides in a region of space inscribed in a wide elliptical cone. The axis of the cone is tilted by ≈30° with respect to the direction of the N-terminal part of the interdomain helix, which is known to have a flexible central part in solution. The C-terminal domain also undergoes rotation about the axis defined by the C-terminal part of the interdomain helix. Neither the extended helix conformation initially observed in the solid state for free calcium calmodulin nor the closed conformation(s) adopted by calcium calmodulin either alone or in its adduct(s) with target peptide(s) is among the most preferred ones. These findings are unique, both in terms of structural information obtained on a biomolecule that samples multiple conformations and in terms of the approach developed to achieve the results. The same approach is in principle applicable to other multidomain proteins, as well as to multiple interaction modes between two macromolecular partners.
Experimentally exploring the conformational space sampled by domain reorientation in calmodulin / Peana, Massimiliano Francesco; Zoroddu, Maria Antonietta. - 101:18(2004), pp. 6841-6846. [10.1073/pnas.0308641101]
File in questo prodotto:
File Dimensione Formato  
Bertini_I_Articolo_2004_Experimentally.pdf

accesso aperto

Tipologia: Versione editoriale (versione finale pubblicata)
Licenza: Non specificato
Dimensione 381.17 kB
Formato Adobe PDF
381.17 kB Adobe PDF Visualizza/Apri

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/11388/264989
Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus ND
  • ???jsp.display-item.citation.isi??? ND
social impact