02065nas a2200277 4500008004100000022001400041245010400055210006900159260000800228300001100236490000900247520113900256653002401395653001901419653001401438653002901452653001601481653001601497100002801513700001601541700001601557700002801573700002601601700003601627856012401663 2020 eng d a0304-416500aMelatonin interacts with repeat domain of Tau to mediate disaggregation of paired helical filaments0 aMelatonin interacts with repeat domain of Tau to mediate disaggr cMAR a1294670 v18643 a

Tau is the major neuronal protein involved in the stabilization of microtubule assembly. In Alzheimer's disease, Tau self-assembles to form intracellular protein aggregates which are toxic to cells. Various methods have been tried and tested to restrain the aggregation of Tau. Most of the agents tested for this purpose have limitations in their effectiveness and availability to neuronal cells. We have tested melatonin, a neurohormone secreted by pineal gland and a well-known anti-oxidant, for its ability to interact with the repeat domain of Tau using ITC and NMR. In aggregation inhibition and disaggregation studies of repeat Tau, melatonin was found to modulate the aggregation propensity of repeat Tau at a concentration of 5000 mu M and was more effective in dissolving preformed aggregates rather than acting as an aggregation inhibitor. However, there were no major conformational changes in Tau in presence of melatonin as observed by CD spectroscopy. On the basis of our findings, we are proposing a mechanism by which melatonin can interact with the repeat domain of Tau and exhibit its disaggregation effect.

10aAlzheimer's disease10aDisaggregation10amelatonin10aPaired helical filaments10atau protein10aTauopathies1 aBalmik, Abhishek, Ankur1 aDas, Rashmi1 aDangi, Abha1 aGorantla, Nalini, Vijay1 aMarelli, Udaya, Kiran1 aChinnathambi, Subashchandrabose uhttp://library.ncl.res.in/content/melatonin-interacts-repeat-domain-tau-mediate-disaggregation-paired-helical-filaments02281nas a2200241 4500008004100000022001400041245010000055210006900155260000800224300001100232490000800243520144900251653002001700653003801720653002501758653001701783653002001800100001601820700002001836700003601856700002601892856012101918 2024 eng d a0045-206800aMacrocyclic peptides derived from AcPHF6*and AcPHF6 to selectively modulate the Tau aggregation0 aMacrocyclic peptides derived from AcPHF6and AcPHF6 to selectivel cOCT a1076250 v1513 a

Ten macrocyclic peptides, each comprising 14 amino acids, were designed and synthesized based on the Tau aggregation model hexapeptides AcPHF6* and AcPHF6. The design took into account the aggregation tendencies of each residue in AcPHF6* and AcPHF6, their aggregation models, while employing peptide-based structural design principles including N-methylation to promote turns and to block hydrogen bond propagation and elongation of the aggregation chain. NMR analysis supported that all these peptides adopted an antiparallel beta-sheet conformation. Self-aggregation studies characterized the aggregation properties of these peptides, identifying two peptides with the highest (P3) and lowest (P8) aggregation tendencies. In cross-aggregation studies with the parent peptides AcPHF6* and AcPHF6, P3 and P8 were found to promote and reduce aggregation, respectively. Furthermore, P3 and P8 demonstrated an enhancement and diminution effect on the aggregation of K18wt, indicating their capacity to modulate aggregation even at the macromolecular level. Thus, the two simple peptides, P3 and P8 selectively exhibit pro- or anti-aggregation effects on PHF peptides and Tau. This study, has thus developed structurally well-defined non-complex peptides, derived from AcPHF6* and AcPHF6, to modulate Tau aggregation as desired, offering applications in Tau model studies and the development of Tau aggregation inhibitors or promoters.

10aCyclic peptides10aPeptide -based drug design (PBDD)10aPeptide conformation10aPHF peptides10aTau Aggregation1 aDangi, Abha1 aQureshi, Tazeen1 aChinnathambi, Subashchandrabose1 aMarelli, Udaya, Kiran uhttp://library.ncl.res.in/content/macrocyclic-peptides-derived-acphf6and-acphf6-selectively-modulate-tau-aggregation01257nas a2200169 4500008004100000022001400041245014400055210006900199260000900268300001400277490000700291520058000298100002300878700002600901700002600927856013400953 2024 eng d a0022-326300aMetal-free one-pot domino synthesis of oxazolidinethione derivatives of quaternary amino acids from α-amino esters and aldehydes using CS20 aMetalfree onepot domino synthesis of oxazolidinethione derivativ cFEB  a7109-71140 v893 a

We present a streamlined, metal-free, one-pot domino approach to efficiently synthesize oxazolidinethione derivatives containing substituted quaternary amino acids. This method employs alpha-amino esters, aldehydes, and CS2 under mild conditions, constructing three new bonds (C-N, C-C, and C-O) to produce oxazolidinethione compounds featuring a quaternary center and a beta-hydroxy derivative in high yields. This scalable protocol enables the creation of libraries of biologically significant, intricate amino acid derivatives using amino esters and aldehydes.

1 aShinde, Dinesh, R.1 aKrishna, Gamidi, Rama1 aMarelli, Udaya, Kiran uhttp://library.ncl.res.in/content/metal-free-one-pot-domino-synthesis-oxazolidinethione-derivatives-quaternary-amino-acids-%CE%B1