Complex formation between calmodulin and a peptide from the intracellular loop of the gap junction protein connexin43: Molecular conformation and energetics of binding

Abstract

. Complex formation between calmodulin and a peptide from the intracellular loop of the gap junction protein connexin43: Molecular conformation and energetics of binding. Biophysical Chemistry, Elsevier, 2009, 144 (3) This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. A C C E P T E D M A N U S C R I P T ACCEPTED MANUSCRIPT AbstractGap junctions are formed by a family of transmembrane proteins, connexins.Connexin43 is a widely studied member of the family, being ubiquitously expressed in a variety of tissues and a target of a large number of disease mutations. The intracellular loop of connexin43 has been shown to include a calmodulin binding domain, but detailed 3-dimensional data on the structure of the complex are not available. In this study, we used a synthetic peptide from this domain to reveal the conformation of the calmodulin-peptide complex by small angle X-ray scattering.Upon peptide binding, calmodulin lost its dumbbell shape, adopting a more globular conformation. We also studied the energetics of the interaction using calorimetry and computational methods. All our data indicate that calmodulin binds to the peptide from cx43 in the classical 'collapsed' conformation.

Structural and Functional Consequences of Connexin 36 (Cx36) Interaction with Calmodulin

“…The Cx36 binding motif is highly conserved across species from humans to lower vertebrates, like lamprey and zebrafish, and overlapping with a CaMKII binding site (Alev et al, 2008). In contrast, the CaM binding sites of Cx35/Cx36 are distinct from other connexins including Cx32, Cx43, Cx44, Cx46, and Cx50 in terms of ligand class (1–8 versus 1–5–10), location of the ligand binding sites, and resemble to date the only connexins activated by CaM (Zhou et al, 2007, 2009; Dodd et al, 2008; Myllykoski et al, 2009; Chen et al, 2011; Xu et al, 2012; Mruk et al, 2014). …”

“…In more general terms, connexins bind CaM with dissociation kinetics and thermodynamic characteristics covering more than a 100-fold range (Dodd et al, 2008; Myllykoski et al, 2009; Zhou et al, 2009; Chen et al, 2011). Together, the specific localization of binding motifs, distinct subclasses and different dissociation kinetics suggest functional adaptations specific for each connexins protein.…”

Charge Isomers of Myelin Basic Protein: Structure and Interactions with Membranes, Nucleotide Analogues, and Calmodulin

“…Synchrotron small-angle X-ray scattering (SAXS) data for rmMBP were collected on beamline I711 [25] at MAX-Lab, Lund, Sweden, and analyzed as previously described [7], [8], [26]. An exposure time of 10 min was used for all samples.…”

“…The final model was obtained in each case from 10 independent ab initio models by averaging by DAMAVER [30]. CaM was used as a molecular weight standard due to its similar size to MBP and previously observed good behaviour in our SAXS experiments [7], [26].…”

Neurological manifestations of oculodentodigital dysplasia: a Cx43 channelopathy of the central nervous system?

“…It has for instance been shown to contain the preferred interaction site for calmodulin (CaM; region 136–158) and as such, to mediate the closure of GJ channels in response to increasing [Ca 2+ ] i (Zhou et al, 2007; Myllykoski et al, 2009). Indeed, Ca 2+ -induced closure of GJs is likely to be mediated by intracellular effector proteins since the uncoupled state may persist long after [Ca 2+ ] i has been restored (Cotrina et al, 1998; Lurtz and Louis, 2003, 2007).…”