Plants contain a large family of so-called calmodulin-like proteins (CMLs) which differ from canonical calmodulin in that they show greater variability in sequence, length, and number of EF-hand domains. The presence of this extended CML family has raised questions regarding the role of these proteins: are they functionally redundant or do they play specific functions in physiological plant processes? To answer these questions, comprehensive biochemical and structural information on CML proteins is fundamental. Among the 50 CMLs from Arabidopsis thaliana, herein we described the ability of CML7 to bind metal ions focusing on the Ca2+ and Mg2+ sensing properties, as well as on metal-induced conformational changes. Circular dichroism and nuclear magnetic resonance (NMR) studies indicated that both Ca2+ and Mg2+ stabilize CML7, as reflected in conformational rearrangements in secondary and tertiary structure and in increases in thermal stability of the protein. However, the conformational changes that binding induces differ between the two metal ions, and only Ca2+ binding controls a structural transition that leads to hydrophobic exposure, as suggested by 8-anilino-1-naphthalenesulfonic acid fluorescence. Isothermal titration calorimetry data coupled with NMR experiments revealed the presence of two high affinity Ca2+-binding sites in the C-lobe of CML7 and two weaker sites in the N-lobe. The paired nature of these CML7 EF-hands enables them to bind Ca2+ with positive cooperativity within each globular domain. Our results clearly place CML7 in the category of Ca2+ sensors. Along with this, the protein can bind to a model target peptide (melittin) in a Ca2+-dependent manner.

Cation and peptide binding properties of CML7, a calmodulin-like protein from Arabidopsis thaliana / M. Trande, M. Pedretti, M.C. Bonza, A. Di Matteo, M. D’Onofrio, P. Dominici, A. Astegno. - In: JOURNAL OF INORGANIC BIOCHEMISTRY. - ISSN 0162-0134. - 199(2019 Oct), pp. 110796.1-110796.13.

Cation and peptide binding properties of CML7, a calmodulin-like protein from Arabidopsis thaliana

M.C. Bonza;
2019

Abstract

Plants contain a large family of so-called calmodulin-like proteins (CMLs) which differ from canonical calmodulin in that they show greater variability in sequence, length, and number of EF-hand domains. The presence of this extended CML family has raised questions regarding the role of these proteins: are they functionally redundant or do they play specific functions in physiological plant processes? To answer these questions, comprehensive biochemical and structural information on CML proteins is fundamental. Among the 50 CMLs from Arabidopsis thaliana, herein we described the ability of CML7 to bind metal ions focusing on the Ca2+ and Mg2+ sensing properties, as well as on metal-induced conformational changes. Circular dichroism and nuclear magnetic resonance (NMR) studies indicated that both Ca2+ and Mg2+ stabilize CML7, as reflected in conformational rearrangements in secondary and tertiary structure and in increases in thermal stability of the protein. However, the conformational changes that binding induces differ between the two metal ions, and only Ca2+ binding controls a structural transition that leads to hydrophobic exposure, as suggested by 8-anilino-1-naphthalenesulfonic acid fluorescence. Isothermal titration calorimetry data coupled with NMR experiments revealed the presence of two high affinity Ca2+-binding sites in the C-lobe of CML7 and two weaker sites in the N-lobe. The paired nature of these CML7 EF-hands enables them to bind Ca2+ with positive cooperativity within each globular domain. Our results clearly place CML7 in the category of Ca2+ sensors. Along with this, the protein can bind to a model target peptide (melittin) in a Ca2+-dependent manner.
calmodulin-like proteins; calcium sensor; EF-hand; Arabidopsis thaliana; melittin
Settore BIO/10 - Biochimica
Settore BIO/04 - Fisiologia Vegetale
   Regulatory signals and redox systems in plant growth-defence trade off
   MINISTERO DELL'ISTRUZIONE E DEL MERITO
   2017ZBBYNC_004
ott-2019
Article (author)
File in questo prodotto:
File Dimensione Formato  
TRande et al 2019.pdf

accesso riservato

Tipologia: Publisher's version/PDF
Dimensione 2.7 MB
Formato Adobe PDF
2.7 MB Adobe PDF   Visualizza/Apri   Richiedi una copia
Pubblicazioni consigliate

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: https://hdl.handle.net/2434/673656
Citazioni
  • ???jsp.display-item.citation.pmc??? 9
  • Scopus 15
  • ???jsp.display-item.citation.isi??? 14
social impact