不同价态金属离子对BSA结构的影响

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SpectrochimicaActaPartA78 (2011) 523–527

ContentslistsavailableatScienceDirect

SpectrochimicaActaPartA:Molecularand

Biomolecular

Spectroscopy

journalhomepage:/locate/sa

a

Toxiceffectsofdifferentchargedmetalionsonthetarget—Bovineserumalbumin

HaoZhang,RutaoLiu ,ZhenxingChi,CanzhuGao

ShandongKeyLaboratoryofWaterPollutionControlandResourceReuse,SchoolofEnvironmentalScienceandEngineering,ShandongUniversity,Jinan250100,PRChinaAmericaCRCforEnvironment&Health,ShandongProvince,27#ShandaSouthRoad,Jinan250100,PRChina

articleinfoabstract

Inthiswork,thetoxicin uenceofmetallicions(Na+,Cu2+,Al3+)ontheserumalbuminwerestudiedby uorescence,resonancelightscattering(RLS),synchronous uorescence,UV–visabsorptionandcirculardichroism(CD)spectroscopy.Theexperimentalresultsindicatedthationelectricchargeisnotthemainfactoraffectingthestructureofbovineserumalbumin(BSA).Na+madethestructureofBSAtighterandhydrophobicityenhanced,whichimproved uorescenceintensity,whileCu2+couldreactwithsomefunctionalgroupsofBSA,makingthestructureofBSAlooser,sothattheinternalhydrophobicgroupssuchastryptophan(Trp)andotheraromaticresiduesweregraduallyexposed.Whenweobservedthemwith uorescencespectra,wefound uorescencequenchingwithincreasingCu2+dose.Al3+isshownaslittlesigni cantin uenceontheBSA,butBSAwasfoundtoaggregatewiththedoseofAl3+bymeansofRLSbecauseofthehydrolysisandionstrengtheffectofAl3+.Theresultsalsoprovednormalsalinecouldkeepliveshealthyandgood-workingasabiologicalhumour,however,heavymetalsmadeharmfuleffectstothebodywhentheyexceededtheminimaleffectlevel(MEL),suchasCu2+choseninourwork.

© 2010 Elsevier B.V. All rights reserved.

Articlehistory:

Received2September2010

Receivedinrevisedform13October2010Accepted15November2010Keywords:Metalions

Bovineserumalbumin(BSA)SpectratechniquesToxicinteraction

1.Introduction

Asisknowntoall,Proteindenaturationreferstothedestructionofthemoleculestructurebyseveralenvironmentalfactorsinclud-ingphysicalandchemicalones,suchastemperature,dehydration,ultravioletradiationandallkindsoftoxicchemicals[1,2].Gener-allyspeaking,proteindenaturationdoesnotcausethedestructionoftheprimarystructurebutthesecondaryone[3,4].Manydis-easessuchasdiabetes,cardiovasculardisease,cataractandmadcowdiseasearepositivelycorrelatedwiththedenaturationofpro-teins[5–8].Wecanalsomaketheproteinfromdenaturationtorenaturation,buttheconditionisveryharsh,weneedputuptherighttime,particulartemperature,pH,andionstrength[9,10]ifwewantthissituationhappen.

SerumAlbumin,themostabundantproteinconstituentinbloodplasma,playsavitalroleinthedispositionandtransportationofvariousmoleculesandcanreactwithmanydifferentligandsinvivoandinvitro.Weselectbovineserumalbumin(BSA)asthetargettoevaluatethetoxiceffectofmetaliononhealthbecauseofitssimilarstructuretohumanserumalbumin(HSA)[11,12]anditslowprice.

Thetoxiceffectsofmetalionstoproteinhavebeenstudiedbytoxicologistssince1990s[13,14].Moreandmoreresearchersstart

tostudytheseeffectsinmolecularlevelatpresent,especiallyana-lyzebindingsitesandparametersbetweenproteinandmetalions.ChuqiaoTuetal.[15]investigatedtheinteractionbetweenCd2+andHSAbymeansofbalanceddialysis,andhefoundthecom-plexcompoundconformationsimilartoatetrahedronafterbindingsitesbetweenCd2+andHSAwereanalyzed.Sadle[16]propoundedapatternbetweenserumalbuminandCd2+,Zn2+withsomeionscoexistinginthesolutionsbynuclearmagneticresonance.Cam-marotetal.[17]learnedtheinhibitionofmatrixmetalloproteinase(mmps)tobodytoxicitybynickelandchromium.Butnoschol-arshavestudiedthetoxicitiesbetweenionsandproteinfromthestandpointofionelectriccharge.Soourgroupsetupthisexperi-menttoinvestigatethisissuethoroughly.WeselectedthreeionswithdifferentelectricchargesNa+,Cu2+,Al3+,andtookBSAasthetargetmoleculetoanalyzethesystemswithspectroscopictech-niques.

2.Materialsandmethods2.1.Apparatus

AHitachiF-4600 uorescencespectrophotometerwasusedtomeasuretheintensityof uorescence,synchronous uores-cenceandRLS.TheUV–visabsorptionspectrumwasobtainedbyaShimadzuUV–2450spectrophotometer.AJasco-810circulardichroismspectrometerwasusedtomeasurethechangesofthesecondarystructureoftheproteinandthepHs-3CpHmeter(Peng-shun,Shanghai,People’sRepublicofChina)wasusedtomeasurethepHinalltheexperiments.

Correspondingauthor.SchoolofEnvironmentalScienceandEngineering,Shan-dongUniversity,Jinan250100PRChina.Tel.:+8653188364868;fax:+8653188364868.

E-mailaddress:rutaoliu@(R.Liu).1386-1425/$–seefrontmatter© 2010 Elsevier B.V. All rights reserved.doi:10.1016/j.saa.2010.11.021

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H.Zhangetal./SpectrochimicaActaPartA78 (2011) 523–527

2.2.Reagents

BSA(electrophoreticreagentgrade)purchasedfromBeijingChemicalReagentCorporationwaspreparedat10 5mol/Landpre-servedat0–4 C.

A0.2mol/LofNaH2PO4-Na2HPO4bufferwaspreparedfromNaH2PO4andNa2HPO4,whichadjustedtotheappropriatepH.

A1.0×10 3mol/LofNaClwaspreparedbydissolving0.0146gNaCl(TsingtaoSifangChemicalReagentFactory)in100mLofultrapurewater.

A1.0×10 3mol/LofCuCl2waspreparedbydissolving0.0427gCuCl2·2H2O(TianjinKermelChemicalReagentResearchInstitute)in100mLofultrapurewater.

A1.0×10 3mol/LofAlCl3waspreparedbydissolving0.0602gAlCl3·6H2O(TianjinDamaoChemicalReagentFactory)in100mLofultrapurewater.3.Methods

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