Dataset Information

Intrinsic disorder and conformational coexistence in auxin coreceptors.

ABSTRACT: AUXIN/INDOLE 3-ACETIC ACID (Aux/IAA) transcriptional repressor proteins and the TRANSPORT INHIBITOR RESISTANT 1/AUXIN SIGNALING F-BOX (TIR1/AFB) proteins to which they bind act as auxin coreceptors. While the structure of TIR1 has been solved, structural characterization of the regions of the Aux/IAA protein responsible for auxin perception has been complicated by their predicted disorder. Here, we use NMR, CD and molecular dynamics simulation to investigate the N-terminal domains of the Aux/IAA protein IAA17/AXR3. We show that despite the conformational flexibility of the region, a critical W-P bond in the core of the Aux/IAA degron motif occurs at a strikingly high (1:1) ratio of cis to trans isomers, consistent with the requirement of the cis conformer for the formation of the fully-docked receptor complex. We show that the N-terminal half of AXR3 is a mixture of multiple transiently structured conformations with a propensity for two predominant and distinct conformational subpopulations within the overall ensemble. These two states were modeled together with the C-terminal PB1 domain to provide the first complete simulation of an Aux/IAA. Using MD to recreate the assembly of each complex in the presence of auxin, both structural arrangements were shown to engage with the TIR1 receptor, and contact maps from the simulations match closely observations of NMR signal-decreases. Together, our results and approach provide a platform for exploring the functional significance of variation in the Aux/IAA coreceptor family and for understanding the role of intrinsic disorder in auxin signal transduction and other signaling systems.

SUBMITTER: Ramans-Harborough S

PROVIDER: S-EPMC10556615 | biostudies-literature | 2023 Oct

REPOSITORIES: biostudies-literature

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Intrinsic disorder and conformational coexistence in auxin coreceptors.

Ramans-Harborough Sigurd S Kalverda Arnout P AP Manfield Iain W IW Thompson Gary S GS Kieffer Martin M Uzunova Veselina V Quareshy Mussa M Prusinska Justyna M JM Roychoudhry Suruchi S Hayashi Ken-Ichiro KI Napier Richard R Genio Charo Del CD Kepinski Stefan S

Proceedings of the National Academy of Sciences of the United States of America 20230927 40

AUXIN/INDOLE 3-ACETIC ACID (Aux/IAA) transcriptional repressor proteins and the TRANSPORT INHIBITOR RESISTANT 1/AUXIN SIGNALING F-BOX (TIR1/AFB) proteins to which they bind act as auxin coreceptors. While the structure of TIR1 has been solved, structural characterization of the regions of the Aux/IAA protein responsible for auxin perception has been complicated by their predicted disorder. Here, we use NMR, CD and molecular dynamics simulation to investigate the N-terminal domains of the Aux/IAA ...[more]

PMID: 37756337

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Dataset Information

Intrinsic disorder and conformational coexistence in auxin coreceptors.

Publications

Intrinsic disorder and conformational coexistence in auxin coreceptors.

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