Preferential Heterodimeric Parallel Coiled-coil Formation by Synthetic Max and c-Myc Leucine Zippers: A Description of Putative Electrostatic Interactions Responsible for the Specificity of Heterodimerization

Lavigne, Pierre; Kondejewski, Leslie H.; Houston, Michael E.; Sönnichsen, Frank D.; Lix, Bruce; Sykes, Brian D.; Hodges, Robert S.; Kay, Cyril M.

doi:10.1006/jmbi.1995.0634

Cited by 111 publications

(122 citation statements)

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“…This implies that this small region may represent a less complex structural target for Myc activity inhibition. Myc E57 and E64 are thought to be involved in interhelical electrostatic interactions, together with Max H60, responsible for heterodimerization specificity (Lavigne et al, 1995). Our data are only partly consistent with this model, as substitution of the two negatively charged glutamic residues with a polar and a nonpolar aminoacid (T and I) aected Myc heterodimerization with Max only weakly (Figure 3b), while it turned out to be essential for Myc homodimerization.…”

Section: Discussioncontrasting

confidence: 38%

Design and properties of a Myc derivative that efficiently homodimerizes

et al. 1998

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bHLH and bHLHZip are highly conserved structural domains mediating DNA binding and speci®c proteinprotein interactions. They are present in a family of transcription factors, acting as dimers, and their selective dimerization is utilized to switch on and o cell proliferation, dierentiation or apoptosis. Myc is a bHLHZip protein involved in growth control and cancer, which operates in a network with the structurally related proteins Max, Mad and Mnt. It does not form homodimers, working as a heterodimer with Max; Max, instead, forms homodimers and heterodimers with Mad and Mnt. Myc/Max dimers activate gene transcription, while Mad/Max and Mnt/Max complexes are Myc/Max antagonists and act as repressors. Modifying the molecular recognition of dimers may provide a tool for interfering with Myc function and, in general, for directing the molecular switches operated via bHLH(Zip) proteins. By molecular modelling and mutagenesis, we analysed the contribution of single amino acids to the molecular recognition of Myc, creating bHLHZip domains with altered dimerization speci®city. We report that Myc recognition speci®city is encoded in a short region within the leucine zipper; mutation of four amino acids generates a protein, Omomyc, that homodimerizes eciently and can still heterodimerize with wild type Myc and Max. Omomyc sequestered Myc in complexes with low DNA binding eciency, preventing binding to Max and inhibiting Myc transcriptional activator function. Consistently with these results, Omomyc produced a proliferation arrest in NIH3T3 cells. These data demonstrate the feasibility of interfering with fundamental biological processes, such as proliferation, by modifying the dimerization selectivity of a bHLHZip protein; this may facilitate the design of peptides of potential pharmacological interest.

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Section: Discussioncontrasting

confidence: 38%

Design and properties of a Myc derivative that efficiently homodimerizes

et al. 1998

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“…For thermal denaturation, ellipticity at 222 nm was measured as a function of temperature. The data were fit using a two-state model (folded dimer and unfolded monomer) as described (21)(22)(23):…”

Section: Circular Dichroism (Cd) Spectroscopy and Denaturation Measurmentioning

confidence: 99%

Molecular Dissection of Rab11 Binding from Coiled-Coil Formation in the Rab11-FIP2 C-Terminal Domain

et al. 2006

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The Rab11-Family Interacting Protein (Rab11-FIP) group of effector proteins contain a highly conserved region in their C-termini that bind the GTPase, Rab11. Rab11 belongs to the largest family of small GTPases and is believed to regulate vesicle docking with target membranes and vesicle fusion. The amino acid sequence of the Rab11-FIP proteins predicts coiled-coil formation in the conserved C-terminal domain. In this study on Rab11-FIP2, we found experimental evidence for the coiled-coil and then defined the minimal structured core using limited proteolysis. We also showed that the Rab11-FIP2 coiled-coil domain forms a parallel homodimer in solution using cross-linking and mutagenesis and sedimentation equilibrium experiments. Various constructs representing the Cterminal domain of Rab11-FIP2 were characterized by circular dichroism and their affinity with Rab11 measured using isothermal titration calorimetry. The longest construct was both wellstructured and bound Rab11. A construct truncated at the N-terminus was poorly structured, but retained the same affinity for binding to Rab11. Conformational changes were also demonstrated upon complex formation between Rab11 and Rab11-FIP2. A construct truncated at the C-terminus, which was the minimal coiled-coil domain defined by limited proteolysis, did not retain the ability to interact with Rab11 although it was as well-structured as the longer peptide. These data show that coiled-coil formation and Rab11 binding are separable functions of the C-terminal domain of Rab11-FIP2. The dissection of Rab11 binding from the formation of defined structure in a coiled-coil provides a potential mechanism for regulating Rab11-dependent endosomal trafficking.

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“…When they are opposite in charge the e residue of one heptad often forms a salt bridge with the g residue of the previous heptad of the opposite helix (32). Such interactions contribute to specificity in FIGURE 5 SPR data presenting the interactions of SEPT6C, SEPT7C, SEPT8C, SEPT10C, and SEPT11C with each other.…”

Section: Primary Structure Analysesmentioning

confidence: 99%

Heterotypic Coiled-Coil Formation is Essential for the Correct Assembly of the Septin Heterofilament

Sala

Valadares

Macêdo

et al. 2016

Biophysical Journal

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Protein-protein interactions play a critical role in promoting the stability of protein quaternary structure and in the assembly of large macromolecular complexes. What drives the stabilization of such assemblies is a central question in biology. A limiting factor in fully understanding such systems is the transient nature of many complexes, making structural studies difficult. Septins comprise a conserved family of guanine nucleotide binding proteins that polymerize in the form of heterofilaments. In structural terms, they have a common organization: a central GTPase domain, an N-terminal domain, and a C-terminal domain; the latter is predicted to form a coiled coil. Currently, even for the best characterized human septin heterocomplex (SEPT2/SEPT6/SEPT7), the role of C-terminal domain is not fully established, and this is partly due to the absence of electron density for the C-terminal domains in the x-ray structure. Here we present results on the homo/heterotypical affinity for the C-terminal domains of human septins belonging to the SEPT6 and SEPT7 groups (SEPT6C/8C/10C/11C and SEPT7C, respectively) and provide clear evidence that this domain determines the preference for heterotypic interactions at one specific interface during the assembly of the heterofilament. This observation has wider implications where macromolecular assemblies are defined by coiled-coil protein interactions.

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Preferential Heterodimeric Parallel Coiled-coil Formation by Synthetic Max and c-Myc Leucine Zippers: A Description of Putative Electrostatic Interactions Responsible for the Specificity of Heterodimerization

Cited by 111 publications

References 0 publications

Design and properties of a Myc derivative that efficiently homodimerizes

Design and properties of a Myc derivative that efficiently homodimerizes

Molecular Dissection of Rab11 Binding from Coiled-Coil Formation in the Rab11-FIP2 C-Terminal Domain

Heterotypic Coiled-Coil Formation is Essential for the Correct Assembly of the Septin Heterofilament

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