盐酸胍诱导八肋游仆虫中心蛋白与XPC肽复合物的解折叠
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摘要
为探索真核生物核苷酸切除修复的可能性,选择人着色性干皮病(XPC)包含中心蛋白结合的多肽为研究对象,采用圆二色谱(CD)、荧光光谱与等温滴定量热法(ITC)对八肋游仆虫中心蛋白(EoCen)的靶肽结合进行了构象与热力学表征.结果表明C端结构域是XPC结合的关键位点,XPC发生构象变化由无规则状态转变为α-螺旋,色氨酸残基镶嵌在C端EF-手形成的疏水腔中,靶肽识别是放热反应,焓变对吉布斯自由能的贡献很大.盐酸胍诱导EoCen-XPC复合物的解折叠机理,并不是使复合物解离,而是使容纳XPC的C端疏水腔瓦解,XPC游离出来.
To explore the possibility of nucleotide excision repair in the eucaryotic organism,we chose a peptide from human xeroderma pigmentosum group C protein(XPC)covering the pivotal centrinbinding region and investigated the conformation and thermodynamic properties of target peptide binding of Euplotes octocarinatus centrin(EoCen)by circular dichroism(CD),fluorescence spectra and isothermal titration calorimetry(ITC).The C-terminal domain was the crucial region that anchored XPC,and XPC underwent conformational transition from a random coil toα-helix.The tryptophan residue of peptide was oriented in the hydrophobic channel formed by C-terminal EF-hand motifs,and peptide recognition of EoCen was exothermic reaction.Enthalpy change contributed to Gibbs free energy greatly.The unfolding mechanism of EoCen-XPC induced by guanidine hydrochloride was not dissociation of complex,but that the hydrophobic channel that hold XPC peptide was collapsed,and XPC peptide was released.
To explore the possibility of nucleotide excision repair in the eucaryotic organism,we chose a peptide from human xeroderma pigmentosum group C protein(XPC)covering the pivotal centrinbinding region and investigated the conformation and thermodynamic properties of target peptide binding of Euplotes octocarinatus centrin(EoCen)by circular dichroism(CD),fluorescence spectra and isothermal titration calorimetry(ITC).The C-terminal domain was the crucial region that anchored XPC,and XPC underwent conformational transition from a random coil toα-helix.The tryptophan residue of peptide was oriented in the hydrophobic channel formed by C-terminal EF-hand motifs,and peptide recognition of EoCen was exothermic reaction.Enthalpy change contributed to Gibbs free energy greatly.The unfolding mechanism of EoCen-XPC induced by guanidine hydrochloride was not dissociation of complex,but that the hydrophobic channel that hold XPC peptide was collapsed,and XPC peptide was released.
引文
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[2]SALISBURY J L,SUINO K M,BUSBY R,et al.[J].Curr Biol,2002,12:1287-1292.
[3]NISHI R,SAKAI W,TONE D,et al.[J].Nucleic Acid Res,2013,41:6917-6929.
[4]FISCHER T,RODRIGUEZ-NAVARRO S,PEREIRA G,et al.[J].Nat Cell Biol,2004,6:840-848.
[5]YANG B S,SONG Z,ZHENG X Y,et al.[J].Sci China Chem,2012,55:1351-1357.
[6]杨斌盛,名洁,宋珍.[J].中国科学:化学,2014,44:646-653.
[7]贺晓静,丰九英,王伟,等.[J].动物学报,2004,50:447-451.
[8]POPESCU A,MIRON S,BLOUQUIT Y,et al.[J].J Biol Chem,2003,278:40252-40261.
[9]GOPAL R,PARK J S,SEO C H,et al.[J].Int J Mol Sci,2012,13:3229-3244.
[10]WANG W M,ZHAO Y Q,WANG H F,et al.[J].Protein Sci,2018,27:1102-1108.
[11]COX J A,TIRONE F,DURUSSEL I,et al.[J].Biochem,2005,44:840-850.
[12]BURSTEIN E A,VEDENKINA N S,IVKOVA M N.[J].Photochem Photobiol,1973,18:263-279.
[13]SHI E X,ZHANG W L,ZHAO Y Q,et al.[J].Metallomics,2017,9:1796-1808.
[14]SHI E X,ZHANG W L,ZHAO Y Q,et al.[J].RSC Adv,2017,7:27139-27149.
[15]THOMPSON J R,CYAN Z C,SALISBURY J L,et al.[J].J Biol Chem,2006,281:18746-18752.
[16]SHI E X,ZHANG W L,YANG B S.[J].J Rare Earth,2018,36:203-208.
[17]CASAS A D,CHAZIN W J,PASTRANA-RíOS B.[J].Biophys J,2017,1129:2529-2539.