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Thermodynamic signature of GCN4-bZIP binding to DNA indicates the role of water in discriminating between the AP-1 and ATF/CREB sites.
J Mol Biol. 2004 Oct 29; 343(4):865-78.JM

Abstract

The energetic basis of GCN4-bZIP complexes with the AP-1 and ATF/CREB sites was investigated by optical methods and scanning and isothermal titration microcalorimetry. The dissociation constant of the bZIP dimer was found to be significantly higher than that of its isolated leucine zipper domain: at 20 degrees C it is 1.45microM and increases with temperature. To avoid complications from dissociation of this dimer, DNA binding experiments were carried out using an SS crosslinked version of the bZIP. The thermodynamic characteristics of the bZIP/DNA association measured at different temperatures and salt concentrations were corrected for the contribution of refolding the basic segment upon binding, determined from the scanning calorimetric experiments. Fluorescence anisotropy titration experiments showed that the association constants of the bZIP at 20 degrees C with the AP-1 and ATF/CREB binding sites do not differ much, being 1.5nM and 6.4nM, corresponding to Gibbs energies of -49kJmol(-1) and -46kJmol(-1), respectively. Almost half of the Gibbs energy is attributable to the electrostatic component, resulting from the entropic effect of counterion release upon DNA association with the bZIP and is identical for both sites. In contrast to the Gibbs energies, the enthalpies of association of the fully folded bZIP with the AP-1 and ATF/CREB sites, and correspondingly the entropies of association, are very different. bZIP binding to the AP-1 site is characterized by a substantially larger negative enthalpy and non-electrostatic entropy than to the ATF/CREB site, implying that the AP-1 complex incorporates significantly more water molecules than the ATF/CREB complex.

Authors+Show Affiliations

Dragan AI
Department of Biology, Johns Hopkins University, Baltimore, MD 21218, USA.
Frank L
No affiliation info available
Liu Y
No affiliation info available
Makeyeva EN
No affiliation info available
Crane-Robinson C
No affiliation info available
Privalov PL
No affiliation info available

MeSH

Activating Transcription FactorsBasic-Leucine Zipper Transcription FactorsBlood ProteinsCyclic AMP Response Element-Binding ProteinDNADNA-Binding ProteinsDimerizationG-Box Binding FactorsProtein BindingProtein KinasesProtein RenaturationSaccharomyces cerevisiae ProteinsTemperatureThermodynamicsTranscription Factor AP-1Transcription FactorsWater

Pub Type(s)

Journal Article
Research Support, U.S. Gov't, P.H.S.

Language

eng

PubMed ID

15476806

Citation

Dragan, Anatoly I., et al. "Thermodynamic Signature of GCN4-bZIP Binding to DNA Indicates the Role of Water in Discriminating Between the AP-1 and ATF/CREB Sites." Journal of Molecular Biology, vol. 343, no. 4, 2004, pp. 865-78.
Dragan AI, Frank L, Liu Y, et al. Thermodynamic signature of GCN4-bZIP binding to DNA indicates the role of water in discriminating between the AP-1 and ATF/CREB sites. J Mol Biol. 2004;343(4):865-78.
Dragan, A. I., Frank, L., Liu, Y., Makeyeva, E. N., Crane-Robinson, C., & Privalov, P. L. (2004). Thermodynamic signature of GCN4-bZIP binding to DNA indicates the role of water in discriminating between the AP-1 and ATF/CREB sites. Journal of Molecular Biology, 343(4), 865-78.
Dragan AI, et al. Thermodynamic Signature of GCN4-bZIP Binding to DNA Indicates the Role of Water in Discriminating Between the AP-1 and ATF/CREB Sites. J Mol Biol. 2004 Oct 29;343(4):865-78. PubMed PMID: 15476806.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Thermodynamic signature of GCN4-bZIP binding to DNA indicates the role of water in discriminating between the AP-1 and ATF/CREB sites. AU - Dragan,Anatoly I, AU - Frank,Leslie, AU - Liu,Yingyun, AU - Makeyeva,Elena N, AU - Crane-Robinson,Colyn, AU - Privalov,Peter L, PY - 2004/06/23/received PY - 2004/08/16/revised PY - 2004/08/26/accepted PY - 2004/10/13/pubmed PY - 2004/12/29/medline PY - 2004/10/13/entrez SP - 865 EP - 78 JF - Journal of molecular biology JO - J Mol Biol VL - 343 IS - 4 N2 - The energetic basis of GCN4-bZIP complexes with the AP-1 and ATF/CREB sites was investigated by optical methods and scanning and isothermal titration microcalorimetry. The dissociation constant of the bZIP dimer was found to be significantly higher than that of its isolated leucine zipper domain: at 20 degrees C it is 1.45microM and increases with temperature. To avoid complications from dissociation of this dimer, DNA binding experiments were carried out using an SS crosslinked version of the bZIP. The thermodynamic characteristics of the bZIP/DNA association measured at different temperatures and salt concentrations were corrected for the contribution of refolding the basic segment upon binding, determined from the scanning calorimetric experiments. Fluorescence anisotropy titration experiments showed that the association constants of the bZIP at 20 degrees C with the AP-1 and ATF/CREB binding sites do not differ much, being 1.5nM and 6.4nM, corresponding to Gibbs energies of -49kJmol(-1) and -46kJmol(-1), respectively. Almost half of the Gibbs energy is attributable to the electrostatic component, resulting from the entropic effect of counterion release upon DNA association with the bZIP and is identical for both sites. In contrast to the Gibbs energies, the enthalpies of association of the fully folded bZIP with the AP-1 and ATF/CREB sites, and correspondingly the entropies of association, are very different. bZIP binding to the AP-1 site is characterized by a substantially larger negative enthalpy and non-electrostatic entropy than to the ATF/CREB site, implying that the AP-1 complex incorporates significantly more water molecules than the ATF/CREB complex. SN - 0022-2836 UR - https://www.unboundmedicine.com/medline/citation/15476806/Thermodynamic_signature_of_GCN4_bZIP_binding_to_DNA_indicates_the_role_of_water_in_discriminating_between_the_AP_1_and_ATF/CREB_sites_ DB - PRIME DP - Unbound Medicine ER -