本文主要研究内容
作者张瑞明（2019）在《典型环境有机污染物的生物酶催化和大气降解反应机理研究》一文中研究指出：酶是指生物体内具有特定空间结构和催化功能的生物大分子,因其催化过程具有专一、高效以及反应条件温和等特性,而被广泛的应用在药物合成以及工、农业生产等领域中。面对我国日益严峻的环境污染问题,生物催化因其催化效率高、能源消耗少、副产物少酶的特点,其在环境领域的研究和应用也开始逐渐得到关注。人们可以利用生物酶高效、专一的特性来降解环境中残留的有机污染物及工业废弃物,以此来缓解当前严峻的生态危机。同时,生物酶技术也可以应用于催化合成或发酵等生产领域中,从而达到减少合成过程中的废弃物排放和能源消耗的目的。随着科技发展进步,实验上研究生物酶催化反应过程的方法也变得更加丰富和多元。目前实验上研究生物酶的主要技术方法有X射线晶体衍射方法、红外色谱法和核磁共振方法等。但是这些实验方法都无法实现对酶催化反应详细过程的描述,这也就阻碍了人们对酶催化科学的认识,从而限制了酶催化理论的应用和发展。量子力学和分子力学(QM/MM)联用的方法可以从原子层面上描述酶催化反应的机理,并对实验上难以检测到的过渡态和短寿命中间体等结构进行理论预测和验证,已经逐步成为研究酶催化反应过程不可或缺的有效工具。本论文采用QM/MM方法研究了生物酶催化降解联苯、卤代联苯和3-氯邻苯二酚的反应机理,从原子水平上描述了酶催化体系反应过程中的详细机理,预测并验证了反应过程中的短寿命过渡态和中间体的结构,明确了酶催化活性中心周围的氨基酸对反应过程产生的静电影响。通过理论与计算化学方的法验证并补充了相关实验结果,丰富和发展了酶催化理论,一定程度上促进了生物酶催化技术在环境中残留有机污染物和工业废弃物治理中的应用。一、联苯脱氢酶对联苯催化降解的机理联苯是化工和制药行业中应用广泛的有机合成前体物,长时间和大范围的使用导致了联苯在环境中大量残留,接触联苯会引起恶心以及呼吸道刺激,严重时会导致肝脏和神经系统受损。特别是其卤代物中的多氯联苯,因其具有脂溶性且可以通过呼吸作用和消化作用在人类的心脏、肝脏和脂肪等组织和器官中富集,进而对人类的健康产生严重威胁。联苯脱氢酶(BphB)属于自然界中广泛存在的短链脱氢和还原酶家族。该类酶可以借助辅酶NAD+的协同催化作用来脱去联苯的两个氢原子来实现对联苯的脱氢降解。BphB酶在联苯、卤代联苯的降解中起至关重要的作用,是联苯类物质经bph催化降解途径中关键的催化酶。本论文应用QM/MM计算方法和动力学模拟方法研究了BphB对联苯的催化脱氢降解反应机理。研究发现:除了去质子化的酪氨酸Tyr155起催化作用外,辅酶NAD+也参与了催化联苯脱氢降解的反应过程,联苯中的两个氢原子通过一步反应分别转移到酪氨酸Tyr155和辅酶NAD+上,即联苯的双脱氢过程是通过一步协同反应完成的,研究结论补充和验证了实验上对脱氢机理的预测。此外本论文还发现丝氨酸Ser142对BphB催化联苯降解过程具有促进作用,而Lys1 59对联苯脱氢降解过程有显著的抑制作用,这一研究发现可以为后续实验上对BphB的定向突变提供理论依据。研究结果加深了对BphB催化降解联苯的认识,可以作为研究BphB酶脱氢降解其他多卤代联苯反应的参考模型。二、联苯脱氢酶在卤代联苯降解过程中的取代基效应多卤代联苯类化合物包括:多氟联苯(PFBs),多氯联苯(PCBs),多溴联苯(PBBs)和多碘联苯(PIBs)。该类化合物曾被广泛应用于液压油、导热油、增塑剂和阻燃剂等,特别是其中的多氯联苯和多溴联苯,曾经在世界范围内被广泛使用,并已大量进入生态环境中。多类卤代联苯因对环境安全有重大威胁而被禁用。多卤代联苯中的多氯联苯和多溴联苯对人体具有很高的致畸性、致癌性和致突变性的“三致”作用。其中仅多氯联苯在环境中的残留量大于28万吨,此种现状更是引起了人们极大地的担忧。本论文通过QM/MM方法联合分子动力学模拟系统的研究了联苯脱氢酶BphB催化卤代联苯降解过程中的取代基效应,揭示了联苯脱氢酶BphB催化卤代联苯(联苯4,4’-位上的,氟代、氯代、溴代以及碘代)的降解机理。实验结果显示:联苯脱氢酶BphB可以高效的降解联苯和4,4’-位二卤代联苯,并且除了氯代联苯外的卤代联苯的玻尔兹曼加权平均降解能垒均低于未被卤素取代的联苯。同时发现联苯脱氢酶BphB降解氟代联苯的能垒最低,并过静电分析和电荷分析等手段解释了联苯脱氢酶BphB降解氟代联苯更高效的原因。此外,研究发现丝氨酸Ser142对BphB降解卤代联苯过程有明显的促进作用,而天冬氨酸Asp143和脯氨酸Pro184对卤代联苯有较为显著的抑制作用,这也为实验上氨基酸的定向突变,寻找更高效的降解卤代联苯降解酶提供了理论基础。本研究结论可以为研究其他多卤代联苯的降解提供理论参考。三、粘康酸内酯脱卤酶对3-氯邻苯二酚的脱氯反应机理氯代芳香族化合物因其具有潜在的毒性、持久性和生物体内积累性而受到关注。环境中的氯代芳香族化合物主要来源于杀虫剂、除草剂、氯化溶剂和工业废料等。长时间大量、无节制的使用有机氯农药,造成了环境中氯代芳香族化合物的大量积聚,导致了严重的环境污染。因此,如何降解环境中大量残留的氯代芳香族化合物已经成为环境领域研究中的一个重要课题。粘康酸内酯脱卤酶属于自然界中大量存在的粘康酸内酯异构酶(MLI)家族,粘康酸内酯脱卤酶是3-氯邻苯二酚降解过程中的第三个催化酶,可以从卤代烷、卤代苯等底物中脱去一分子的HCl并将其转化为含碳碳双键的化合物。该酶因其对底物具有有宽泛的选择性和较高效的脱卤降解能力,在降解氯代化合物上有宽广的应用前景。本论文以5-氯粘康酸内酯为例,使用QM/MM方法和动力学模拟研究了粘康酸内酯脱卤酶降解5-氯粘康酸内酯的反应机理。通过比对活性中心的氨基酸验证了粘康酸内酯脱卤酶的活性中心是由两个单体共同组成。粘康酸内酯脱卤酶降解5-氯粘康酸内酯是分两步完成,分别是氢抽提步骤和氯的消除反应,其氯的消除为降解过程的速控反应步骤。通过分析活性中心周围八种氨基酸对氢转移反应的静电影响发现,色氨酸Trp40和谷氨酸Glu51对速控反应有显著的促进作用,而精氨酸Arg45对该速控步反应步骤有明显的抑制作用,这一发现可为后续的实验酶改造提供理论依据和支持。四、大气中4-羟基-2-丁酮的氧化降解机理近年来,高浓度的含氧挥发性有机化合物(OVOCs)在全球对流层中被广泛的检测出来,OVOCs对大气层的污染也越来越被人们所关注。作为典型的OVOCs,4-羟基-2-丁酮(CH3CO-CH2CH2OH)广泛应用于合成制药、食品生产和精细化学品加工等行业。由于其在大气中易于蒸发,4-羟基-2-丁酮在其生产和使用过程中很容易被排放和泄露到大气中,导致二次有机污染的生成,如对流层臭氧和光化学烟雾等。特别是其气相降解过程产生的过氧酰基硝酸酯中间体,是大气中光化学烟雾的重要成分和NOx远距离传输的重要载体。本论文中采用了量子化学计算方法基于 MPWB1K/6-311+G(3df,2p)//MPWB11K/6-31+G(d,p)水平上详细的研究了 OH自由基与4-羟基-2-丁酮的大气反应机理。提出并验证了 4-羟基-2-丁酮与OH自由基大气降解过程中可能的反应路径、中间体和产物。并采用POLYRATE9.7计算了各分支反应和总反应的速率常数。298 K时的总反应速率为1.64 × 10-12 cm3 molecule-1 s-1。在一级反应路径中,OH自由基抽提4-羟基-2-丁酮C3-H键上的氢原子时,反应能垒是各路径中最低的且该过程为放热反应,是最易发生的反应路径。4-羟基-2-丁酮与大气中OH自由基反应的主要产物有甲醛、过氧自由基和不饱和醛酮化合物。本章中通过推导详细的机理、描述寿命较短的中间体和速率常数等来解释、补充和验证了相关实验的结论,这有助于更好的评估4-羟基-2-丁酮对大气可能的潜在影响。
Abstract
mei shi zhi sheng wu ti nei ju you te ding kong jian jie gou he cui hua gong neng de sheng wu da fen zi ,yin ji cui hua guo cheng ju you zhuan yi 、gao xiao yi ji fan ying tiao jian wen he deng te xing ,er bei an fan de ying yong zai yao wu ge cheng yi ji gong 、nong ye sheng chan deng ling yu zhong 。mian dui wo guo ri yi yan jun de huan jing wu ran wen ti ,sheng wu cui hua yin ji cui hua xiao lv gao 、neng yuan xiao hao shao 、fu chan wu shao mei de te dian ,ji zai huan jing ling yu de yan jiu he ying yong ye kai shi zhu jian de dao guan zhu 。ren men ke yi li yong sheng wu mei gao xiao 、zhuan yi de te xing lai jiang jie huan jing zhong can liu de you ji wu ran wu ji gong ye fei qi wu ,yi ci lai huan jie dang qian yan jun de sheng tai wei ji 。tong shi ,sheng wu mei ji shu ye ke yi ying yong yu cui hua ge cheng huo fa jiao deng sheng chan ling yu zhong ,cong er da dao jian shao ge cheng guo cheng zhong de fei qi wu pai fang he neng yuan xiao hao de mu de 。sui zhao ke ji fa zhan jin bu ,shi yan shang yan jiu sheng wu mei cui hua fan ying guo cheng de fang fa ye bian de geng jia feng fu he duo yuan 。mu qian shi yan shang yan jiu sheng wu mei de zhu yao ji shu fang fa you Xshe xian jing ti yan she fang fa 、gong wai se pu fa he he ci gong zhen fang fa deng 。dan shi zhe xie shi yan fang fa dou mo fa shi xian dui mei cui hua fan ying xiang xi guo cheng de miao shu ,zhe ye jiu zu ai le ren men dui mei cui hua ke xue de ren shi ,cong er xian zhi le mei cui hua li lun de ying yong he fa zhan 。liang zi li xue he fen zi li xue (QM/MM)lian yong de fang fa ke yi cong yuan zi ceng mian shang miao shu mei cui hua fan ying de ji li ,bing dui shi yan shang nan yi jian ce dao de guo du tai he duan shou ming zhong jian ti deng jie gou jin hang li lun yu ce he yan zheng ,yi jing zhu bu cheng wei yan jiu mei cui hua fan ying guo cheng bu ke huo que de you xiao gong ju 。ben lun wen cai yong QM/MMfang fa yan jiu le sheng wu mei cui hua jiang jie lian ben 、lu dai lian ben he 3-lv lin ben er fen de fan ying ji li ,cong yuan zi shui ping shang miao shu le mei cui hua ti ji fan ying guo cheng zhong de xiang xi ji li ,yu ce bing yan zheng le fan ying guo cheng zhong de duan shou ming guo du tai he zhong jian ti de jie gou ,ming que le mei cui hua huo xing zhong xin zhou wei de an ji suan dui fan ying guo cheng chan sheng de jing dian ying xiang 。tong guo li lun yu ji suan hua xue fang de fa yan zheng bing bu chong le xiang guan shi yan jie guo ,feng fu he fa zhan le mei cui hua li lun ,yi ding cheng du shang cu jin le sheng wu mei cui hua ji shu zai huan jing zhong can liu you ji wu ran wu he gong ye fei qi wu zhi li zhong de ying yong 。yi 、lian ben tuo qing mei dui lian ben cui hua jiang jie de ji li lian ben shi hua gong he zhi yao hang ye zhong ying yong an fan de you ji ge cheng qian ti wu ,chang shi jian he da fan wei de shi yong dao zhi le lian ben zai huan jing zhong da liang can liu ,jie chu lian ben hui yin qi e xin yi ji hu xi dao ci ji ,yan chong shi hui dao zhi gan zang he shen jing ji tong shou sun 。te bie shi ji lu dai wu zhong de duo lv lian ben ,yin ji ju you zhi rong xing ju ke yi tong guo hu xi zuo yong he xiao hua zuo yong zai ren lei de xin zang 、gan zang he zhi fang deng zu zhi he qi guan zhong fu ji ,jin er dui ren lei de jian kang chan sheng yan chong wei xie 。lian ben tuo qing mei (BphB)shu yu zi ran jie zhong an fan cun zai de duan lian tuo qing he hai yuan mei jia zu 。gai lei mei ke yi jie zhu fu mei NAD+de xie tong cui hua zuo yong lai tuo qu lian ben de liang ge qing yuan zi lai shi xian dui lian ben de tuo qing jiang jie 。BphBmei zai lian ben 、lu dai lian ben de jiang jie zhong qi zhi guan chong yao de zuo yong ,shi lian ben lei wu zhi jing bphcui hua jiang jie tu jing zhong guan jian de cui hua mei 。ben lun wen ying yong QM/MMji suan fang fa he dong li xue mo ni fang fa yan jiu le BphBdui lian ben de cui hua tuo qing jiang jie fan ying ji li 。yan jiu fa xian :chu le qu zhi zi hua de lao an suan Tyr155qi cui hua zuo yong wai ,fu mei NAD+ye can yu le cui hua lian ben tuo qing jiang jie de fan ying guo cheng ,lian ben zhong de liang ge qing yuan zi tong guo yi bu fan ying fen bie zhuai yi dao lao an suan Tyr155he fu mei NAD+shang ,ji lian ben de shuang tuo qing guo cheng shi tong guo yi bu xie tong fan ying wan cheng de ,yan jiu jie lun bu chong he yan zheng le shi yan shang dui tuo qing ji li de yu ce 。ci wai ben lun wen hai fa xian si an suan Ser142dui BphBcui hua lian ben jiang jie guo cheng ju you cu jin zuo yong ,er Lys1 59dui lian ben tuo qing jiang jie guo cheng you xian zhe de yi zhi zuo yong ,zhe yi yan jiu fa xian ke yi wei hou xu shi yan shang dui BphBde ding xiang tu bian di gong li lun yi ju 。yan jiu jie guo jia shen le dui BphBcui hua jiang jie lian ben de ren shi ,ke yi zuo wei yan jiu BphBmei tuo qing jiang jie ji ta duo lu dai lian ben fan ying de can kao mo xing 。er 、lian ben tuo qing mei zai lu dai lian ben jiang jie guo cheng zhong de qu dai ji xiao ying duo lu dai lian ben lei hua ge wu bao gua :duo fu lian ben (PFBs),duo lv lian ben (PCBs),duo xiu lian ben (PBBs)he duo dian lian ben (PIBs)。gai lei hua ge wu ceng bei an fan ying yong yu ye ya you 、dao re you 、zeng su ji he zu ran ji deng ,te bie shi ji zhong de duo lv lian ben he duo xiu lian ben ,ceng jing zai shi jie fan wei nei bei an fan shi yong ,bing yi da liang jin ru sheng tai huan jing zhong 。duo lei lu dai lian ben yin dui huan jing an quan you chong da wei xie er bei jin yong 。duo lu dai lian ben zhong de duo lv lian ben he duo xiu lian ben dui ren ti ju you hen gao de zhi ji xing 、zhi ai xing he zhi tu bian xing de “san zhi ”zuo yong 。ji zhong jin duo lv lian ben zai huan jing zhong de can liu liang da yu 28mo dun ,ci chong xian zhuang geng shi yin qi le ren men ji da de de dan you 。ben lun wen tong guo QM/MMfang fa lian ge fen zi dong li xue mo ni ji tong de yan jiu le lian ben tuo qing mei BphBcui hua lu dai lian ben jiang jie guo cheng zhong de qu dai ji xiao ying ,jie shi le lian ben tuo qing mei BphBcui hua lu dai lian ben (lian ben 4,4’-wei shang de ,fu dai 、lv dai 、xiu dai yi ji dian dai )de jiang jie ji li 。shi yan jie guo xian shi :lian ben tuo qing mei BphBke yi gao xiao de jiang jie lian ben he 4,4’-wei er lu dai lian ben ,bing ju chu le lv dai lian ben wai de lu dai lian ben de bo er ci man jia quan ping jun jiang jie neng lei jun di yu wei bei lu su qu dai de lian ben 。tong shi fa xian lian ben tuo qing mei BphBjiang jie fu dai lian ben de neng lei zui di ,bing guo jing dian fen xi he dian he fen xi deng shou duan jie shi le lian ben tuo qing mei BphBjiang jie fu dai lian ben geng gao xiao de yuan yin 。ci wai ,yan jiu fa xian si an suan Ser142dui BphBjiang jie lu dai lian ben guo cheng you ming xian de cu jin zuo yong ,er tian dong an suan Asp143he fu an suan Pro184dui lu dai lian ben you jiao wei xian zhe de yi zhi zuo yong ,zhe ye wei shi yan shang an ji suan de ding xiang tu bian ,xun zhao geng gao xiao de jiang jie lu dai lian ben jiang jie mei di gong le li lun ji chu 。ben yan jiu jie lun ke yi wei yan jiu ji ta duo lu dai lian ben de jiang jie di gong li lun can kao 。san 、nian kang suan nei zhi tuo lu mei dui 3-lv lin ben er fen de tuo lv fan ying ji li lv dai fang xiang zu hua ge wu yin ji ju you qian zai de du xing 、chi jiu xing he sheng wu ti nei ji lei xing er shou dao guan zhu 。huan jing zhong de lv dai fang xiang zu hua ge wu zhu yao lai yuan yu sha chong ji 、chu cao ji 、lv hua rong ji he gong ye fei liao deng 。chang shi jian da liang 、mo jie zhi de shi yong you ji lv nong yao ,zao cheng le huan jing zhong lv dai fang xiang zu hua ge wu de da liang ji ju ,dao zhi le yan chong de huan jing wu ran 。yin ci ,ru he jiang jie huan jing zhong da liang can liu de lv dai fang xiang zu hua ge wu yi jing cheng wei huan jing ling yu yan jiu zhong de yi ge chong yao ke ti 。nian kang suan nei zhi tuo lu mei shu yu zi ran jie zhong da liang cun zai de nian kang suan nei zhi yi gou mei (MLI)jia zu ,nian kang suan nei zhi tuo lu mei shi 3-lv lin ben er fen jiang jie guo cheng zhong de di san ge cui hua mei ,ke yi cong lu dai wan 、lu dai ben deng de wu zhong tuo qu yi fen zi de HClbing jiang ji zhuai hua wei han tan tan shuang jian de hua ge wu 。gai mei yin ji dui de wu ju you you kuan fan de shua ze xing he jiao gao xiao de tuo lu jiang jie neng li ,zai jiang jie lv dai hua ge wu shang you kuan an de ying yong qian jing 。ben lun wen yi 5-lv nian kang suan nei zhi wei li ,shi yong QM/MMfang fa he dong li xue mo ni yan jiu le nian kang suan nei zhi tuo lu mei jiang jie 5-lv nian kang suan nei zhi de fan ying ji li 。tong guo bi dui huo xing zhong xin de an ji suan yan zheng le nian kang suan nei zhi tuo lu mei de huo xing zhong xin shi you liang ge chan ti gong tong zu cheng 。nian kang suan nei zhi tuo lu mei jiang jie 5-lv nian kang suan nei zhi shi fen liang bu wan cheng ,fen bie shi qing chou di bu zhou he lv de xiao chu fan ying ,ji lv de xiao chu wei jiang jie guo cheng de su kong fan ying bu zhou 。tong guo fen xi huo xing zhong xin zhou wei ba chong an ji suan dui qing zhuai yi fan ying de jing dian ying xiang fa xian ,se an suan Trp40he gu an suan Glu51dui su kong fan ying you xian zhe de cu jin zuo yong ,er jing an suan Arg45dui gai su kong bu fan ying bu zhou you ming xian de yi zhi zuo yong ,zhe yi fa xian ke wei hou xu de shi yan mei gai zao di gong li lun yi ju he zhi chi 。si 、da qi zhong 4-qiang ji -2-ding tong de yang hua jiang jie ji li jin nian lai ,gao nong du de han yang hui fa xing you ji hua ge wu (OVOCs)zai quan qiu dui liu ceng zhong bei an fan de jian ce chu lai ,OVOCsdui da qi ceng de wu ran ye yue lai yue bei ren men suo guan zhu 。zuo wei dian xing de OVOCs,4-qiang ji -2-ding tong (CH3CO-CH2CH2OH)an fan ying yong yu ge cheng zhi yao 、shi pin sheng chan he jing xi hua xue pin jia gong deng hang ye 。you yu ji zai da qi zhong yi yu zheng fa ,4-qiang ji -2-ding tong zai ji sheng chan he shi yong guo cheng zhong hen rong yi bei pai fang he xie lou dao da qi zhong ,dao zhi er ci you ji wu ran de sheng cheng ,ru dui liu ceng chou yang he guang hua xue yan wu deng 。te bie shi ji qi xiang jiang jie guo cheng chan sheng de guo yang xian ji xiao suan zhi zhong jian ti ,shi da qi zhong guang hua xue yan wu de chong yao cheng fen he NOxyuan ju li chuan shu de chong yao zai ti 。ben lun wen zhong cai yong le liang zi hua xue ji suan fang fa ji yu MPWB1K/6-311+G(3df,2p)//MPWB11K/6-31+G(d,p)shui ping shang xiang xi de yan jiu le OHzi you ji yu 4-qiang ji -2-ding tong de da qi fan ying ji li 。di chu bing yan zheng le 4-qiang ji -2-ding tong yu OHzi you ji da qi jiang jie guo cheng zhong ke neng de fan ying lu jing 、zhong jian ti he chan wu 。bing cai yong POLYRATE9.7ji suan le ge fen zhi fan ying he zong fan ying de su lv chang shu 。298 Kshi de zong fan ying su lv wei 1.64 × 10-12 cm3 molecule-1 s-1。zai yi ji fan ying lu jing zhong ,OHzi you ji chou di 4-qiang ji -2-ding tong C3-Hjian shang de qing yuan zi shi ,fan ying neng lei shi ge lu jing zhong zui di de ju gai guo cheng wei fang re fan ying ,shi zui yi fa sheng de fan ying lu jing 。4-qiang ji -2-ding tong yu da qi zhong OHzi you ji fan ying de zhu yao chan wu you jia quan 、guo yang zi you ji he bu bao he quan tong hua ge wu 。ben zhang zhong tong guo tui dao xiang xi de ji li 、miao shu shou ming jiao duan de zhong jian ti he su lv chang shu deng lai jie shi 、bu chong he yan zheng le xiang guan shi yan de jie lun ,zhe you zhu yu geng hao de ping gu 4-qiang ji -2-ding tong dui da qi ke neng de qian zai ying xiang 。
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论文作者分别是来自山东大学的张瑞明，发表于刊物山东大学2019-07-16论文，是一篇关于方法论文,联苯脱氢酶论文,粘康酸内酯脱卤酶论文,催化反应机理论文,山东大学2019-07-16论文的文章。本文可供学术参考使用，各位学者可以免费参考阅读下载，文章观点不代表本站观点，资料来自山东大学2019-07-16论文网站，若本站收录的文献无意侵犯了您的著作版权，请联系我们删除。
标签：方法论文; 联苯脱氢酶论文; 粘康酸内酯脱卤酶论文; 催化反应机理论文; 山东大学2019-07-16论文;