Atomic water channel controlling remarkable properties of a single brain microtubule: Correlating single protein to its supramolecular assembly

Microtubule nanotubesarefoundineverylivingeukaryoticcells;theseareformedbyreversible polymerizationofthetubulinprotein,andtheirhollow fibersare filledwithuniquelyarrangedwater molecules.Herewemeasuresingletubulinmoleculeandsinglebrain-neuronextractedmicrotubule nanowirewithandwithoutwaterchannelinsidetounraveltheiruniqueelectronicandopticalproperties for the firsttime.Wedemonstratethattheenergylevelsofasingletubulinproteinandsinglemicrotubule madeof40,000tubulindimersareidenticalunlikeconventionalmaterials.Moreover,thetransmittedac powerandthetransient fluorescencedecay(singlephotoncount)areindependentofthemicrotubule length.Evenmoreremarkableisthefactthatthemicrotubulenanowireismoreconductingthanasingle proteinmoleculethatconstitutesthenanowire.Microtubule's vibrationalpeakscondensetoasinglemode thatcontrolstheemergenceofsizeindependentelectronic/opticalproperties,andautomatednoise alleviation,whichdisappearwhentheatomicwatercoreisreleasedfromtheinnercylinder.Wehave carriedoutseveraltrickystate-of-the-artexperimentsandidentified theelectromagneticresonancepeaksof singlemicrotubulereliably.Theresonantvibrationsestablishedthatthecondensationofenergylevelsand periodicoscillationofuniqueenergyfringesonthemicrotubulesurface,emergeastheatomicwatercore resonantlyintegratesallproteinsarounditsuchthatthenanotubeirrespectiveofitssizefunctionslikea singleproteinmolecule.Thus,amonomolecularwaterchannelresidinginsidetheprotein-cylinderdisplays an unprecedentedcontrolingoverningthetantalizingelectronicandopticalpropertiesofmicrotubule.