1P146 Heat capacity changes of proteins relate to temperature dependence of water density(Water & Hydration & Electrolyte,The 48th Annual Meeting of the Biophysical Society of Japan)
1P146 蛋白質の熱容量変化量と水の数密度の温度依存性の関係(水・水和/電解質,第48回日本生物物理学会年会)

junji yasuniwa, masayuki irisa
2010 Seibutsu Butsuri  
TheBiophysical Society of Japan General IncorporatedAssociation so catled structure breakcr lons As well as the LlassiLal MD resultb the QM results of water around phosphatc moleLutes witt be shown IP1451El255 IkuoKuTrsakt long and water though recent expenmLntal studiLs reported thaL new and noteworthy findmgs about roles of -ater and ions in biosystems the roles are not fully Lxammed Furthermore many ciasgical rnolecular dynamics (MD) simulaUons wtrL done to rcx eal molecular inechanisms of
more » ... ogystemg However it ig well known that Lonventional water models (TIP3P TIP4P TIPSP SCP etc ) used in MD Ldnnot repreduce the dynamics ot water around ions cven quahtanvcly The anomalous behavior of water around ions would indllectly affeLt dylldmiLs et biomaeromoleLule In this study we attempt to refine the water model to reproduce the dynamics in monovalent ion water s}stems We impreived the force ficld parameters of TIP5P water model one of the most re]iable water mode]s in thc irame ot datssical MD The ratio of transldtional self diffusion coefucients ot water in the first water layer to that ol bulk water and thL rotational relaxduen time dre examined to assegs translauona] and rotdtional motion respectlvdy We sucLeed ]n reproduLmg the dynamiLs of water around an ion The detatls wi]] be presented on thc board rk"+E7JVopdiRCIS6rlr7r),OreD ¢ *"7fiitYrlrV-;oxoptam Reproductionofdynamicgofwateraroundanionbyrehn]ng water model Tlakuvl Thkzhash (CollFgeofide Sctences RFtsumeikan Un"vers)rv) are important players in most of biological phenomena Al IP146 diefiOajasfiE{tgee*OXeaNOfiRtuetr ¢ eeca Heat capauty changes of proteins relate to temperature de pendencL of -atLr denb]ty junJi vDgum-a mnsnyuk ms] CKvtishii Insrtrure oflechnetag} Crad"ak Sthoot ojComp"tet ScrenLe arld SystEms Engrneenng) We have cellcuielted heat eapacity changes by usmg extLnded scaled paTti cle theory (XSPT) Heat eapacity changes haNe been empiriLally regarded as contnbutions from h}drophobic hydrations m [he field ot calonmLtnc ex perlments The hydrophobic contnbutions can be denved m XSur from the hypotheticat work to make a cavity in water for accommodating a protein moleLule Experimentally obtained number densities ot pure water and thoge tempcraturL dependenLes are iieeessary m XSPT Both number densities of water and those temperature dcnvauvets affect heat capaemeb oi a piotem In this work at the point of view what affects the hydration entropy and the hydrophobic part of hydrauen heat capacity fora protem we foeubed on the expression of the equation of thc statL (EOS) of pure watLr which dLtLiminLs temperature dcpendence of number density for pure wdter We tried some pelynomidi expresstons of the EOS to reproduce the temperature dependence ot the number density We have calculated heat capacity changes of a protein along the curve ot saturatlon vapor pressure in order to reproduce super cooled elnd super heated conditions The temperature dependence of pure water strongly affects the convergence temperature whcre every protein has the save regularized eiitropy change per atom 120 Celsius degree in ourcalculatien IP148 ATP&UVYmaco*flttmamaut pah#le7pt-eeONee I E1310 H)drdtio" properties of lYT? aiid phosphate correlation with the thermodynamic parameters Ccorge Mognnl[1 Takde Kodtmd2 Maketo Suz"kil CIGradtsak SchoolofEngtneermg 7ohoku C ni i{-T4 "IFReC O"akcr Uniwnttv) In the mo hydrolysis reaction AI/P + H20 > ADP + Pt Onorganic phos phate) reactant and pioduct undergo guccessive matLhmg iemzeltions -ith pH ln general hydrationtree energies of iens are very large so it is 1ikely that the diffLrencc m thobL betwecn reaLtant and product spcucts its d magor factor LontributingtothefreeenergyofptIrPhydrolysis,asfirstsuggestedbyGeorge et at in 1970 For its quanutative argument however it is of prerequlslte te know the hydration propei ties of speues mvolved In view of the fact that the releNanttomespeciesdormnantatpH>8areATT'4' ADP' andHP042 we attemptedtemeasurethedynamiLrotauonalmobitityofwaterhydraungthese ions We prepared aqueous solutions of sodium salts of xe ADP andi Pi and ac!Justed their pH to 8 O which were then sub]ectLd to high resolutaon dielec tnc relaxation (DR) spectroscopy m the frequenLy range from O 2 to 26 GHz at 200C Solutions ofhalide saltg ofatkaline rnetals were separatLl} meabured to take mto account the effect of countcracting cations on the DR properties of the ArP ADP and Pi solutions The results thus obtained indicate that around the said dmens there exist erdmary constrdlned water with DR frequency if,) in the GH7 range and hyper mobile water withf, highcr than that of bulk water O) in 1iving systcms It has been pointed out that the Gibbs energy of nv hydiol ysis depends on the diderent solvauon energies of ieactants (MP and water) and products (ADP and P,) Thus it is crucial to determine the contnbuUon of hydratton to the MP hydrolysis energy FoT this purpose AG for hydrauon of MP ADP and P, are needed to estimite by measurement of distnbution coeficients between aqueous and orgdnic sol vents As the first step the selubility ofMP ADP and P, in vanous orgamc solventg (butanol pentanot hexanot octano] and chloroform) was tegted As expected hLghly charged mo ADP and P, were slight]y dissolved Tn the or ganic solvents However supplementation witb fatty acid amine (steary]arnine and Lerylamine) dramatically mLredsed the selubihty of ArP ADP and P, in organic solvents confirming the findmg by Plaut (J Biol Chem 195e 184 243) In these solvents the dinme groupts are surrounded by hydropho bic groups which environmentg are similar to the protein intenor Thus the solvatien of MP ADP and P, m the fatty aLid aniine Lentammg selvLnt may mimic the association of these compounds with protein More mterestmgly the go]ubJ]]ty ot AIIP wis higheT than those ot ADP and P, implying the dif feienLeofsolvationenergybetweenreaLtantsandproductsotAI'Phydrolysis IP150ID1435 KenJt MuTakam1 lhkevukiWakaba]ashi]4 VniversiO "Departmoent ofBos"ente ftnd B:tnntbrmattts Lngtneettng Kytshti lnsrftute of fochnolog} rt;teotAdLancedJnduslrtatSctenteandfeehnotogy ftchnolog) ktino Lntversin) Act]n polymcn7ation tTiggers acuvation of afP hydrolygig which provides the gtructural cueg for filament turnover m vivo Assembled fiLaments support eeJlular sLgnalmg inuaLL]lular trathLking and cytokmebis A high rcsolution structure of actin filarnent s esgentiat for understanding the mechanism of aetin polymenLation and MPase acbvation wr present the eleetron eryo microscopic {EM) gtructure of filamentous actm <F actin) in the presence of phosphate with some a helical backboncg and laLge sidc chams being dirLctly visualized This indicates that the reselution of the dedrest part m the EM map is in a 6 7 Angstrom range A complete atemic model based on the EM map identified mtei molccu}ai mteractions mediated by bound magnesium and phosphate ions Compdred with thL mollome-L actan (G aLtm) LhL con served Pre mch loop Crcsidues 108 112) in F ADP+Pi ac"n adoptg a moTe bent conformtikon which t-ggers opemng of a phosphate re!eabmg pathway
doi:10.2142/biophys.50.s45_2 fatcat:gxddtmtppbbezmvawb6ohcnv7q