Grants and Contracts Details
Description
In recent years it has become apparent that intrinsically disordered regions (IDR5) within proteins are extremely
common and often involved in important biological functions. IDRs have been found to play crucial roles in
transcription, signaling pathways and immune systems in higher organisms. IDR5 are involved in numerous
diseases states including cardiovascular and protein aggregation diseases. IDRs often function by undergoing a
disorder to order transition when bound by another protein (i.e. they fold upon binding). It has been
hypothesized that Nature has evolved disordered binding regions in order to partially decouple binding specificity
from affinity. In other words, what is bound is somewhat decoupled from how strongly it is bound. An extremely
important system that appears to take advantage of this disorder-mediated decoupling is calmodulin (CaM) and
its binding targets (CaMBT5). Unbound CaMBT sequences are often disordered. When CaM binds, it induces, in
most cases, a-helical structure in the CaMBT. We propose using this system to test the hypothesis that
disorder partially decouples specificity from affinity. Under this hypothesis specificity is determined by the
residues that directly contact CaM. Affinity is determined in part by the propensity for the unbound CaMBT to
adopt a-helical structure. We can modulate the a-helicity of CaMBT peptides by altering residues on either side
of the CaMBT, thereby altering the affinity without changing specificity. The extent to which we have altered the
a-helicity of the CaMBTs is readily determined using circular dichroism spectroscopy, while binding affinity can
be determined using fluorescence and/or isothermal titration calorimetry. Should the hypothesis hold, we would
expect a positive correlation between the measured a-helix contents and the binding affinities. This system will
serve to generate the preliminary data necessary for future studies of the reasons behind Nature's widespread
use of lDRs in critical molecular recognition processes.
Status | Finished |
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Effective start/end date | 7/1/08 → 12/31/11 |
Funding
- KY Science and Technology Co Inc: $69,999.00
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