Intra- versus intermolecular interactions in monellin: Contribution of surface charges to protein assembly

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Intra- versus intermolecular interactions in monellin: Contribution of surface charges to protein assembly. / Xue, Wei-Feng; Szczepankiewicz, Olga; Bauer, Mikael; Thulin, Eva; Linse, Sara.

I: Journal of Molecular Biology, Vol. 358, Nr. 5, 2006, s. 1244-1255.

Forskningsoutput: TidskriftsbidragArtikel i vetenskaplig tidskrift

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Xue, Wei-Feng ; Szczepankiewicz, Olga ; Bauer, Mikael ; Thulin, Eva ; Linse, Sara. / Intra- versus intermolecular interactions in monellin: Contribution of surface charges to protein assembly. I: Journal of Molecular Biology. 2006 ; Vol. 358, Nr. 5. s. 1244-1255.

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TY - JOUR

T1 - Intra- versus intermolecular interactions in monellin: Contribution of surface charges to protein assembly

AU - Xue, Wei-Feng

AU - Szczepankiewicz, Olga

AU - Bauer, Mikael

AU - Thulin, Eva

AU - Linse, Sara

PY - 2006

Y1 - 2006

N2 - The relative significance of weak non-covalent interactions in biological context has been much debated. Here, we have addressed the contribution of Coulombic interactions to protein stability and assembly experimentally. The sweet protein monellin, a non-covalently linked heterodimeric protein, was chosen for this study because of its ability to spontaneously reconstitute from separated fragments. The reconstitution of monellin mutants containing large surface charge perturbations was compared to the thermostability of structurally equivalent single-chain monellin containing the same sets of mutations under varying salt concentrations. The affinity between monellin fragments is found to correlate with the thermostability of single chain monellin, indicating the involvement of the same underlying Coulombic interactions. This confirms that there are no principal differences in the interactions involved in folding and binding. Based on comparison with a previous mutational study involving hydrophobic core residues, the relative contribution of Coulombic interactions to stability and affinity is modest. However, the Coulombic perturbations only affect the association rates of reconstitution in contrast to perturbations involving hydrophobic residues, which affect primarily the dissociation rates. These results indicate that Coulombic interactions are likely to be of main importance for the association of protein assembly, relevant for functions of proteins. (c) 2006 Elsevier Ltd. All rights reserved.

AB - The relative significance of weak non-covalent interactions in biological context has been much debated. Here, we have addressed the contribution of Coulombic interactions to protein stability and assembly experimentally. The sweet protein monellin, a non-covalently linked heterodimeric protein, was chosen for this study because of its ability to spontaneously reconstitute from separated fragments. The reconstitution of monellin mutants containing large surface charge perturbations was compared to the thermostability of structurally equivalent single-chain monellin containing the same sets of mutations under varying salt concentrations. The affinity between monellin fragments is found to correlate with the thermostability of single chain monellin, indicating the involvement of the same underlying Coulombic interactions. This confirms that there are no principal differences in the interactions involved in folding and binding. Based on comparison with a previous mutational study involving hydrophobic core residues, the relative contribution of Coulombic interactions to stability and affinity is modest. However, the Coulombic perturbations only affect the association rates of reconstitution in contrast to perturbations involving hydrophobic residues, which affect primarily the dissociation rates. These results indicate that Coulombic interactions are likely to be of main importance for the association of protein assembly, relevant for functions of proteins. (c) 2006 Elsevier Ltd. All rights reserved.

KW - interactions

KW - electrostatic

KW - protein reconstitution

KW - fragment complementation

KW - global analysis

KW - protein folding and binding

U2 - 10.1016/j.jmb.2006.02.069

DO - 10.1016/j.jmb.2006.02.069

M3 - Article

VL - 358

SP - 1244

EP - 1255

JO - Journal of Molecular Biology

JF - Journal of Molecular Biology

SN - 1089-8638

IS - 5

ER -