These tools will no longer be maintained as of December 31, 2024. Archived website can be found here. PubMed4Hh GitHub repository can be found here. Contact NLM Customer Service if you have questions.


Pubmed for Handhelds

PUBMED FOR HANDHELDS

Search MEDLINE/PubMed

  • Title: Structural requirements and thermodynamics of the interaction of proline peptides with profilin.
    Author: Petrella EC, Machesky LM, Kaiser DA, Pollard TD.
    Journal: Biochemistry; 1996 Dec 24; 35(51):16535-43. PubMed ID: 8987987.
    Abstract:
    The binding to poly(L-proline) is used for the affinity purification of profilins, but little is known about the structural and thermodynamic aspects of the interaction. We used changes in the intrinsic fluorescence of profilin, CD spectroscopy, and isothermal titration calorimetry to assess how the size and composition of synthetic proline-rich peptides influence binding to Acanthamoeba and human profilins. Although a 6 residue type II poly(L-proline) helix can span the binding site, highest affinity binding is achieved by proline oligomers > or = 10 residues. Binding is stereospecific since (D-proline)11 does not bind. In 75 mM KCI the dissociation equilibrium constant for poly(L-proline) is about 10 microM proline decamer units for amoeba profilin and 20-30 microM for human profilin. Consistent with a significant hydrophobic component of the interaction, delta Cp is negative and higher salt concentrations enhance the affinity. No protons dissociate or bind during the interaction. Binding of poly(L-proline) is favored both entropically and enthalpically. Substitution of glycine in proline undecamers reduces affinity by about 1 kcal mol-1 for each substitution due to increased rotational freedom of the free peptides. Substitution of alanine has a similar effect. Disorder in the free peptides imparts an unfavorable entropic cost for immobilizing the substituted peptides on the binding site on profilin.
    [Abstract] [Full Text] [Related] [New Search]