02380nas a2200265   4500008004100000022001400041245016600055210006900221260000900290300001400299490000700313520144700320653002801767653002501795653002901820653001301849653001401862653001101876100001701887700002201904700002201926700001601948700002401964856012601988       2024                        eng d  a1948-719300aDNA-mediated formation of phase-separated coacervates of the nucleic acid-binding domain of TAR DNA-binding protein (TDP-43) prevents its amyloid-like misfolding0 aDNAmediated formation of phaseseparated coacervates of the nucle  cOCT   a4105-41220 v153 a<p>
	Sequestration of protein molecules and nucleic acids to stress granules is one of the most promising strategies that cells employ to protect themselves from stress. In vitro, studies suggest that the nucleic acid-binding domain of TDP-43 (TDP-43tRRM) undergoes amyloid-like aggregation to beta-sheet-rich structures in low pH stress. In contrast, we observed that the TDP-43tRRM undergoes complex coacervation in the presence of ssDNA to a dense and light phase, preventing its amyloid-like aggregation. The soluble light phase consists of monomeric native-like TDP-43tRRM. The microscopic data suggest that the dense phase consists of spherical coacervates with limited internal dynamics. We performed multiparametric analysis by employing various biophysical techniques and found that complex coacervation depends on the concentration and ratio of the participating biomolecules and is driven by multivalent interactions. The modulation of these forces due to environmental conditions or disease mutations regulates the extent of coacervation, and the weakening of interactions between TDP-43tRRM and ssDNA leads to amyloid-like aggregation of TDP-43tRRM. Our results highlight a competition among the native state, amyloid-like aggregates, and complex coacervates tuned by various environmental factors. Together, our results illuminate an alternate function of TDP-43tRRM in response to pH stress in the presence of the ssDNA.</p>
10aamyloid-likeaggregation10acomplex coacervation10aDNA-protein interactions10aDynamics10apH stress10aTDP-431 aPatni, Divya1 aPatil, Anjali, D.1 aKirmire, Mona, S.1 aJha, Anjali1 aJha, Santosh, Kumar  uhttps://library.ncl.res.in/content/dna-mediated-formation-phase-separated-coacervates-nucleic-acid-binding-domain-tar-dna02704nas a2200253   4500008004100000022001400041245012700055210006900182260000800251300001400259490000700273520183800280653002002118653002702138653002202165653001902187653002402206653001402230100002202244700002202266700001502288700002402303856012302327       2024                        eng d  a1948-719300aPathological mutations D169G and P112H electrostatically aggravate the amyloidogenicity of the functional domain of TDP-430 aPathological mutations D169G and P112H electrostatically aggrava  cNOV  a4267-42830 v153 a<p>
	Aggregation of TDP-43 is linked to the pathogenesis of many neurodegenerative diseases, including amyotrophic lateral sclerosis (ALS). Notably, electrostatic point mutations such as D169G and P112H, located within the highly conserved functional tandem RNA recognition motif (RRM) domains of the TDP-43 protein (TDP-43tRRM), have been identified in diseased patients as well. In this study, we address how the electrostatic mutations alter both the native state stability and aggregation propensity of TDP-43tRRM. The mutants D169G and P112H show increased chemical stability compared to the TDP-43tRRM at physiological pH. However, at low pH, both the mutants undergo a conformational change to form amyloid-like fibrils, though with variable rates-the P112H mutant being substantially faster than the other two sequences (TDP-43tRRM and D169G mutant) showing comparable rates. Moreover, among the three sequences, only the P112H mutant undergoes a strong ionic strength-dependent aggregability trend. These observations signify the substantial contribution of the excess charge of the P112H mutant to its unique aggregation process. Complementary simulated observables with atomistic resolution assign the experimentally observed sequence-, pH-, and ionic strength-dependent aggregability pattern to the degree of thermal lability of the mutation site-containing RRM1 domain and its extent of dynamical anticorrelation with the RRM2 domain whose combination eventually dictate the extent of generation of aggregation-prone partially unfolded conformational ensembles. Our choice of a specific charge-modulated pathogenic mutation-based experiment-simulation-combination approach unravels the otherwise hidden residue-wise contribution to the individual steps of this extremely complicated multistep aggregation process.</p>
10aamyloid fibrils10aconformational changes10adisease mutations10aelectrostatics10aProtein aggregation10astability1 aPillai, Meenakshi1 aPatil, Anjali, D.1 aDas, Atanu1 aJha, Santosh, Kumar  uhttps://library.ncl.res.in/content/pathological-mutations-d169g-and-p112h-electrostatically-aggravate-amyloidogenicity