Get access

Intrinsic structural disorder of mouse proNGF

Authors

  • Francesca Paoletti,

    Corresponding author
    1. SISSA-ISAS, Building Q1, Area Science Park - Basovizza, S.S 14 Km 163.5, 34012 Trieste, Italy
    2. European Brain Research Institute, Via del Fosso di Fiorano 64, 00143 Rome, Italy
    • EBRI—European Brain Research Institute—“Rita Levi-Montalcini” Foundation, Via del Fosso di Fiorano, 64, I-00143 Roma
    Search for more papers by this author
  • Sonia Covaceuszach,

    1. LayLine Genomics S.p.A., via di Castel Romano 100, 00128 Roma, Italy
    Search for more papers by this author
  • Peter V. Konarev,

    1. European Molecular Biology Laboratory, Hamburg Outstation, Notkestrasse 85, 22603 Hamburg, Germany
    2. Institute of Crystallography, Russian Academy of Sciences, Leninsky pr. 59, 117333 Moscow, Russia
    Search for more papers by this author
  • Stefania Gonfloni,

    1. SISSA-ISAS, Building Q1, Area Science Park - Basovizza, S.S 14 Km 163.5, 34012 Trieste, Italy
    2. Department of Biology, University of Rome Tor Vergata, I-00133 Rome, Italy
    Search for more papers by this author
  • Francesca Malerba,

    1. European Brain Research Institute, Via del Fosso di Fiorano 64, 00143 Rome, Italy
    Search for more papers by this author
  • Elisabeth Schwarz,

    1. Institut for Biochemistry and Biotechnology, Martin-Luther-University Halle-Wittenberg, 06120 Halle (Saale), Germany
    Search for more papers by this author
  • Dmitri I. Svergun,

    1. European Molecular Biology Laboratory, Hamburg Outstation, Notkestrasse 85, 22603 Hamburg, Germany
    2. Institute of Crystallography, Russian Academy of Sciences, Leninsky pr. 59, 117333 Moscow, Russia
    Search for more papers by this author
  • Antonino Cattaneo,

    1. SISSA-ISAS, Building Q1, Area Science Park - Basovizza, S.S 14 Km 163.5, 34012 Trieste, Italy
    2. European Brain Research Institute, Via del Fosso di Fiorano 64, 00143 Rome, Italy
    Search for more papers by this author
  • Doriano Lamba

    Corresponding author
    1. Istituto di Cristallografia - CNR, Area Science Park - Basovizza, S.S 14 Km 163.5, 34012 Trieste, Italy
    • Istituto di Cristallografia, C.N.R., Unità Staccata di Trieste, Area Science Park, Basovizza Strada Statale 14, Km 163.5 I-34012 Trieste, Italy
    Search for more papers by this author

Abstract

The unprocessed precursor of the Nerve Growth Factor (NGF), proNGF, has additional functions, besides its initially described role as a chaperone for NGF folding. The precursor protein endows apoptotic and/or neurotrophic properties, in contrast to the mature part. The structural and molecular basis for such distinct activities are presently unknown. Aiming to gain insights into the specific molecular interactions that govern rm-proNGF biological activities versus those of its mature counterpart, a structural study by synchrotron small angle X-ray scattering (SAXS) in solution was carried out. The different binding properties of the two proteins were investigated by surface plasmon resonance (SPR) using, as structural probes, a panel of anti-NGF antibodies and the soluble forms of TrkA and p75NTR receptors. SAXS measurements revealed the rm-proNGF to be dimeric and anisometric, with the propeptide domain being intrinsically unstructured. Ab initio reconstructions assuming twofold symmetry generated two types of structural models, a globular “crab-like” and an elongated shape that resulted in equally good fits of the scattering data. A novel method accounting for possible coexistence of different conformations contributing to the experimental scattering pattern, with no symmetry constraints, suggests the “crab-like” to be a more likely proNGF conformation. To exploit the potential of chemical stabilizers affecting the existing conformational protein populations, SAXS data were also collected in the presence of ammonium sulphate. An increase of the proNGF compactness was observed. SPR data pinpoints that the propeptide of proNGF may act as an intrinsically unstructured protein domain, characterized by a molecular promiscuity in the interaction/binding to multiple partners (TrkA and p75NTR receptors and a panel of neutralizing anti-NGF antibodies) depending on the physiological conditions of the cell. These data provide a first insight into the structural basis for the selectivity of mouse short proNGF, versus NGF, towards its binding partners. Proteins 2009. © 2008 Wiley-Liss, Inc.

Ancillary