Polyphosphate discriminates protein conformational ensembles more efficiently than DNA promoting diverse assembly and maturation behaviors

Disordered proteins and domains often assemble into condensates with polyanionic nucleic acids, primarily via charge complementarity, regulating numerous cellular functions. However, the assembly mechanisms associated with the other abundant and ubiquitous, anionic, stress–response regulating polyme...

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Main Authors: Saloni Goyal, Divya Rajendran, Anup Kumar Mani, Athi N Naganathan
Format: Article
Language:English
Published: eLife Sciences Publications Ltd 2025-07-01
Series:eLife
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Online Access:https://elifesciences.org/articles/105461
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author Saloni Goyal
Divya Rajendran
Anup Kumar Mani
Athi N Naganathan
author_facet Saloni Goyal
Divya Rajendran
Anup Kumar Mani
Athi N Naganathan
author_sort Saloni Goyal
collection DOAJ
description Disordered proteins and domains often assemble into condensates with polyanionic nucleic acids, primarily via charge complementarity, regulating numerous cellular functions. However, the assembly mechanisms associated with the other abundant and ubiquitous, anionic, stress–response regulating polymer, polyphosphate (polyP), are less understood. Here, we employ the intrinsically disordered DNA-binding domain (DBD) of cytidine repressor (CytR) from E. coli to study the nature of assembly processes with polyP and DNA. CytR forms metastable liquid-like condensates with polyP and DNA, while undergoing liquid-to-solid transition in the former and dissolving in the latter. On mutationally engineering the ensemble to exhibit more or less structure and dimensions than the WT, the assembly process with polyP is directed to either condensates with partial time-dependent dissolution or spontaneous aggregation, respectively. On the other hand, the CytR variants form only liquid-like but metastable droplets with DNA which dissolve within a few hours. Polyphosphate induces large secondary-structure changes, with two of the mutants adopting polyproline II-like structures within droplets, while DNA has only minimal structural effects. Our findings reveal how polyphosphate can more efficiently discern conformational heterogeneity in the starting protein ensemble, its structure, and compactness, with broad implications in assembly mechanisms involving polyP and stress response in bacterial systems.
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spelling doaj-art-c050abe954374fa68d4a6f4dec8139a92025-08-20T03:50:32ZengeLife Sciences Publications LtdeLife2050-084X2025-07-011410.7554/eLife.105461Polyphosphate discriminates protein conformational ensembles more efficiently than DNA promoting diverse assembly and maturation behaviorsSaloni Goyal0Divya Rajendran1Anup Kumar Mani2Athi N Naganathan3https://orcid.org/0000-0002-1655-7802Department of Biotechnology, Bhupat and Jyoti Mehta School of Biosciences, Indian Institute of Technology Madras, Chennai, IndiaDepartment of Biotechnology, Bhupat and Jyoti Mehta School of Biosciences, Indian Institute of Technology Madras, Chennai, IndiaDepartment of Biotechnology, Bhupat and Jyoti Mehta School of Biosciences, Indian Institute of Technology Madras, Chennai, IndiaDepartment of Biotechnology, Bhupat and Jyoti Mehta School of Biosciences, Indian Institute of Technology Madras, Chennai, IndiaDisordered proteins and domains often assemble into condensates with polyanionic nucleic acids, primarily via charge complementarity, regulating numerous cellular functions. However, the assembly mechanisms associated with the other abundant and ubiquitous, anionic, stress–response regulating polymer, polyphosphate (polyP), are less understood. Here, we employ the intrinsically disordered DNA-binding domain (DBD) of cytidine repressor (CytR) from E. coli to study the nature of assembly processes with polyP and DNA. CytR forms metastable liquid-like condensates with polyP and DNA, while undergoing liquid-to-solid transition in the former and dissolving in the latter. On mutationally engineering the ensemble to exhibit more or less structure and dimensions than the WT, the assembly process with polyP is directed to either condensates with partial time-dependent dissolution or spontaneous aggregation, respectively. On the other hand, the CytR variants form only liquid-like but metastable droplets with DNA which dissolve within a few hours. Polyphosphate induces large secondary-structure changes, with two of the mutants adopting polyproline II-like structures within droplets, while DNA has only minimal structural effects. Our findings reveal how polyphosphate can more efficiently discern conformational heterogeneity in the starting protein ensemble, its structure, and compactness, with broad implications in assembly mechanisms involving polyP and stress response in bacterial systems.https://elifesciences.org/articles/105461polyphosphateDNAaggregatesmaturationcondensatesspectroscopy
spellingShingle Saloni Goyal
Divya Rajendran
Anup Kumar Mani
Athi N Naganathan
Polyphosphate discriminates protein conformational ensembles more efficiently than DNA promoting diverse assembly and maturation behaviors
eLife
polyphosphate
DNA
aggregates
maturation
condensates
spectroscopy
title Polyphosphate discriminates protein conformational ensembles more efficiently than DNA promoting diverse assembly and maturation behaviors
title_full Polyphosphate discriminates protein conformational ensembles more efficiently than DNA promoting diverse assembly and maturation behaviors
title_fullStr Polyphosphate discriminates protein conformational ensembles more efficiently than DNA promoting diverse assembly and maturation behaviors
title_full_unstemmed Polyphosphate discriminates protein conformational ensembles more efficiently than DNA promoting diverse assembly and maturation behaviors
title_short Polyphosphate discriminates protein conformational ensembles more efficiently than DNA promoting diverse assembly and maturation behaviors
title_sort polyphosphate discriminates protein conformational ensembles more efficiently than dna promoting diverse assembly and maturation behaviors
topic polyphosphate
DNA
aggregates
maturation
condensates
spectroscopy
url https://elifesciences.org/articles/105461
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AT divyarajendran polyphosphatediscriminatesproteinconformationalensemblesmoreefficientlythandnapromotingdiverseassemblyandmaturationbehaviors
AT anupkumarmani polyphosphatediscriminatesproteinconformationalensemblesmoreefficientlythandnapromotingdiverseassemblyandmaturationbehaviors
AT athinnaganathan polyphosphatediscriminatesproteinconformationalensemblesmoreefficientlythandnapromotingdiverseassemblyandmaturationbehaviors