Consequences of inducing intrinsic disorder in a high-affinity protein-protein interaction

Papadakos, Grigorius, Sharma, Amit, Lancaster, Lorna , Bowen, Rebecca, Kaminska, Renata, Leech, Andrew P, Walker, Daniel, Redfield, Christina and Kleanthous, Colin (2015) Consequences of inducing intrinsic disorder in a high-affinity protein-protein interaction. Journal of the American Chemical Society, 137 (16). pp. 5252-5255. ISSN 0002-7863

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The kinetic and thermodynamic consequences of intrinsic disorder in protein-protein recognition are controversial. We address this by inducing one partner of the high-affinity colicin E3 rRNase domain-Im3 complex (Kd ≈ 10(-12) M) to become an intrinsically disordered protein (IDP). Through a variety of biophysical measurements, we show that a single alanine mutation at Tyr507 within the hydrophobic core of the isolated colicin E3 rRNase domain causes the enzyme to become an IDP (E3 rRNase(IDP)). E3 rRNase(IDP) binds stoichiometrically to Im3 and forms a structure that is essentially identical to the wild-type complex. However, binding of E3 rRNase(IDP) to Im3 is 4 orders of magnitude weaker than that of the folded rRNase, with thermodynamic parameters reflecting the disorder-to-order transition on forming the complex. Critically, pre-steady-state kinetic analysis of the E3 rRNase(IDP)-Im3 complex demonstrates that the decrease in affinity is mostly accounted for by a drop in the electrostatically steered association rate. Our study shows that, notwithstanding the advantages intrinsic disorder brings to biological systems, this can come at severe kinetic and thermodynamic cost.

Keywords:Intrinsic disorder, Protein Protein interaction, colicin E3, JCOpen
Subjects:C Biological Sciences > C700 Molecular Biology, Biophysics and Biochemistry
Divisions:College of Science > School of Pharmacy
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ID Code:17517
Deposited On:27 May 2015 08:52

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