Dataset Information

Predicted disorder-to-order transition mutations in I?B? disrupt function.

ABSTRACT: I?B? inhibits the transcription factor, NF?B, by forming a very tightly bound complex in which the ankyrin repeat domain (ARD) of I?B? interacts primarily with the dimerization domain of NF?B. The first four ankyrin repeats (ARs) of the I?B? ARD are well-folded, but the AR5-6 region is intrinsically disordered according to amide H/D exchange and protein folding/unfolding experiments. We previously showed that mutations towards the consensus sequence for stable ankyrin repeats resulted in a "prefolded" mutant. To investigate whether the consensus mutations were solely able to order the AR5-6 region, we used a predictor of protein disordered regions PONDR VL-XT to select mutations that would alter the intrinsic disorder towards a more ordered structure (D ? O mutants). The algorithm predicted two mutations, E282W and P261F, neither of which correspond to the consensus sequence for ankyrin repeats. Amide exchange and CD were used to assess ordering. Although only the E282W was predicted to be more ordered by CD and amide exchange, stopped-flow fluorescence studies showed that both of the D ? O mutants were less efficient at dissociating NF?B from DNA.

SUBMITTER: Dembinski H

PROVIDER: S-EPMC4040282 | biostudies-literature | 2014 Apr

REPOSITORIES: biostudies-literature

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Predicted disorder-to-order transition mutations in IκBα disrupt function.

Dembinski Holly H Wismer Kevin K Balasubramaniam Deepa D Gonzalez Hector A HA Alverdi Vera V Iakoucheva Lilia M LM Komives Elizabeth A EA

Physical chemistry chemical physics : PCCP 20140306 14

IκBα inhibits the transcription factor, NFκB, by forming a very tightly bound complex in which the ankyrin repeat domain (ARD) of IκBα interacts primarily with the dimerization domain of NFκB. The first four ankyrin repeats (ARs) of the IκBα ARD are well-folded, but the AR5-6 region is intrinsically disordered according to amide H/D exchange and protein folding/unfolding experiments. We previously showed that mutations towards the consensus sequence for stable ankyrin repeats resulted in a "pref ...[more]

PMID: 24605363

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Project description:The effects of disease mutations on protein structure and function have been extensively investigated, and many predictors of the functional impact of single amino acid substitutions are publicly available. The majority of these predictors are based on protein structure and evolutionary conservation, following the assumption that disease mutations predominantly affect folded and conserved protein regions. However, the prevalence of the intrinsically disordered proteins (IDPs) and regions (IDRs) in the human proteome together with their lack of fixed structure and low sequence conservation raise a question about the impact of disease mutations in IDRs. Here, we investigate annotated missense disease mutations and show that 21.7% of them are located within such intrinsically disordered regions. We further demonstrate that 20% of disease mutations in IDRs cause local disorder-to-order transitions, which represents a 1.7-2.7 fold increase compared to annotated polymorphisms and neutral evolutionary substitutions, respectively. Secondary structure predictions show elevated rates of transition from helices and strands into loops and vice versa in the disease mutations dataset. Disease disorder-to-order mutations also influence predicted molecular recognition features (MoRFs) more often than the control mutations. The repertoire of disorder-to-order transition mutations is limited, with five most frequent mutations (R?W, R?C, E?K, R?H, R?Q) collectively accounting for 44% of all deleterious disorder-to-order transitions. As a proof of concept, we performed accelerated molecular dynamics simulations on a deleterious disorder-to-order transition mutation of tumor protein p63 and, in agreement with our predictions, observed an increased ?-helical propensity of the region harboring the mutation. Our findings highlight the importance of mutations in IDRs and refine the traditional structure-centric view of disease mutations. The results of this study offer a new perspective on the role of mutations in disease, with implications for improving predictors of the functional impact of missense mutations.

Dataset Information

Predicted disorder-to-order transition mutations in I?B? disrupt function.

Publications

Predicted disorder-to-order transition mutations in IκBα disrupt function.

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