Depletion of squalene epoxidase in synergy with glutathione peroxidase 4 inhibitor RSL3 overcomes oxidative stress resistance in lung squamous cell carcinoma

Background:Lung squamous cell carcinoma(Lusc)lacks effective targeted therapies and has a poor prognosis.Disruption of squalene epoxidase(SQLE)has been implicated in metabolic disorders and cancer.However,the role of SQLE as a monooxygenase involved in oxidativestressremainsunclear.Methods:We analyzed the expression and prognosis of lung adenocarcinoma(LUAD)and LUSC samples from GEO and TCGA databases.The proliferative activity of the tumors after intervention of SQLE was verified by cell and animal experiments.JC-1 assay,flow cytometry,and Western blot were used to show changes in apoptosis after intervention of sQLE.Flow cytometry and fluorescence assay of ROs levels were used to indicate oxidative stress status.Results:We investigated the unique role of SQLE expression in the diagnosis and prognosis prediction of LUSC.Knockdown of SQLE or treatment with the SQLE inhibitor terbinafine can suppress the proliferation of LUsC cells by inducing apoptosis and reactive oxygen species accumulation.However,depletion of SQLE also results in the impairment of lipid peroxidation and ferroptosis resistance such as upregulation of glutathione peroxidase 4.Therefore,prevention of SQLE in synergy with glutathione peroxidase 4 inhibitor RSL3 effectively mitigates the proliferation and growth of LUSC.Conclusion:Our study indicates that the low expression of sQLE employs adaptive survival through regulating the balance of apoptosis and ferroptosis resistance.In future,the combinational therapy of targeting sQLE and ferroptosis could be a promising approach in treating LUSC.

Physical exercise reverses immuno-cold tumor microenvironment via inhibiting SQLE in non-small cell lung cancer

Dear Editor,Physical exercise has been shown to be associated with reduced cancer incidence and cancer-associated mortality[1,2],but the underlying mechanisms are obscure.Immunometabolic regulation has emerged as one of the most prominent mechanisms explaining the effects of exercise on cancer[1,2].Physical exercise primarily lowers blood cholesterol and triglycerides,and protects against cardiovascular diseases[3].However,whether physical exercise can modulate cholesterol metabolism in tumor cells is currently unknown.

Transcriptome-Wide Identification and Functional Analysis of PgSQE08-01 Gene in Ginsenoside Biosynthesis in Panax ginseng C.A.Mey.

Panax ginseng C.A.Mey.is an important plant species used in traditional Chinese medicine,whose primary active ingredient is a ginsenoside.Ginsenoside biosynthesis is not only regulated by transcription factors but also controlled by a variety of structural genes.Nonetheless,the molecular mechanism underlying ginsenoside biosynthesis has always been a topic in the discussion of ginseng secondary metabolites.Squalene epoxidase(SQE)is a key enzyme in the mevalonic acid pathway,which affects the biosynthesis of secondary metabolites such as terpenoid.Using ginseng transcriptome,expression,and ginsenoside content databases,this study employed bioinformatic methods to systematically analyze the genes encoding SQE in ginseng.We first selected six PgSQE candidates that were closely involved in ginsenoside biosynthesis and then identified PgSQE08-01 to be highly associated with ginsenoside biosynthesis.Next,we constructed the overexpression vector pCAMBIA3301-PgSQE08-01 and the RNAi vector pART27-PgSQE08-01 and transformed ginseng adventitious roots using Agrobacterium rhizogenes,to obtain positive hairy-root clones.Thereafter,quantitative reverse transcriptionpolymerase chain reaction and high-performance liquid chromatography were used to determine the expression of relevant genes and ginsenoside content,respectively.Then,we focused on the function of PgSQE08-01 gene,which was noted to be involved in ginsenoside biosynthesis.Thus,these findings not only provided a molecular basis for the identification of important functional genes in ginseng but also enriched genetic resources for the biosynthesis of ginsenosides using synthetic biology.

Arabidopsis Squalene Epoxidase 3 （SQE3） Complements SQE1 and Is Important for Embryo Development and Bulk Squalene Epoxidase Activity

The existence of multigenic families in the mevalonate pathway suggests divergent functional roles for pathway components involved in the biosynthesis of plant sterols. Squalene epoxidases （SQEs） are key components of this pathway, and Squalene Epoxidase 1 （SQE1） has been identified as a fundamental enzyme in this biosynthetic step. In the present work, we extended the characterization of the remaining SQE family members, phylogenetically resolving between true SQEs and a subfamily of SQE-like proteins that is exclusive to Brassicaceae. Functional characterization of true SQE family members, Squalene Epox- idase 2 （SQE2） and Squalene Epoxidase 3 （SQE3）, indicates that SQE3, but not SQE2, contributes to the bulk SQE activity in Arabidopsis, with sqe3-1 mutants accumulating squalene and displaying sensitivity to ter- binafine. We genetically demonstrated that SQE3 seems to play a particularly significant role in embryo development. Also, SQE1 and SQE3 both localize in the endoplasmic reticulum, and SQE3 can functionally complement SQEI. Thus, SQE1 and SQE3 seem to be two functionally unequal redundant genes in the pro- motion of plant SQE activity in Arabidopsis.

Molecular Cloning and Expression of Squalene Epoxidase from a Medicinal Plant, Bupleurum chinense

Objective In plant, squalene epoxidase （SE） catalyzes the first oxygenation step in the biosynthetic pathway of triterpenoid and phytosterol, representing one of the rate-limiting enzymes in this pathway. Bupleurum chinense is an important medicinal herb with its major active constituents such as triterpenoid saponins and saikosaponins. In order to obtain the series of enzymatic genes involved in saikosaponin biosynthesis, a cDNA of SE, designated BcSEI, was cloned from B. chinense. Methods The BcSEI gene was cloned by homology-based PCR and 5＇/3＇ RACE methods from the adventitious roots of B. chinense. The physical and chemical parameters of BcSE1 protein were predicted by protparam. In order to discover hints in amino acid sequences on the dominant functions in the biosynthesis of saponin or phytosterol, sequences of SE from other plants were downloaded from NCBI for sequences alignment and phylogenetic analysis. BcSEI was cloned into a yeast mutant KLNI （MATa, ergl.＇：URA3, leu2, ura3, and trpl） to verify the enzyme activity of BcSE1. Additionally, the tissue-specific expression and methyl jasmonate （MeJA） inducibility of BcSEI were investigated using quantitative real-time PCR. Results The predicted protein of BcSE1 is highly similar to SEs from other plants sharing amino acid sequence identities of up to 88%. The BcSEI can functionally complement with yeast SE gene （ERGI） when expressed in the KLNI mutant （MATa, ergl：：URA3, leu2, ura3, and trpl）. Using as controls with ^-amyrin synthase （G-AS） which is presumed to catalyze the first committed step in saikosaponin biosynthesis and a cycloartenol synthase （CAS） relating to the phytosterol biosynthesis, the transcript of BcSE1 was significantly elevated by MeJA in adventitious roots of B. chinenseand the transcript of BcSElwas most abundant in the fruits and flowers of plants, followed by that in the leaves and roots, and least in stems. Conclusion It is the first time to illustrate the molecular information of SE in B. chinense and to clone the full-length SEgene in plants of genus Bupleurum L.

Squalene epoxidase promotes colorectal cancer cell proliferation through accumulating calcitriol and activating CYP24A1-mediatedMAPK signaling

Background:Colorectal cancer(CRC)is one of the most malignant tumorswith high incidence,yet its molecular mechanism is not fully understood,hindering the development of targeted therapy.Metabolic abnormalities are a hallmark of cancer.Targeting dysregulated metabolic features has become an important direction for modern anticancer therapy.In this study,we aimed to identify a new metabolic enzyme that promotes proliferation of CRC and to examine the related molecular mechanisms.Methods:We performed RNA sequencing and tissue microarray analyses of human CRC samples to identify new genes involved in CRC.Squalene epoxidase(SQLE)was identified to be highly upregulated in CRC patients.The regulatory function of SQLE in CRC progression and the therapeutic effect of SQLE inhibitors were determined by measuring CRC cell viability,colony and organoid formation,intracellular cholesterol concentration and xenograft tumor growth.Themolecularmechanism of SQLE functionwas explored by combining transcriptome and untargeted metabolomics analysis.Western blotting and realtime PCR were used to assess MAPK signaling activation by SQLE.Results:SQLE-related control of cholesterol biosynthesis was highly upregulated in CRC patients and associated with poor prognosis.SQLE promoted CRC growth in vitro and in vivo.Inhibition of SQLE reduced the levels of calcitriol(active form of vitamin D3)and CYP24A1,followed by an increase in intracellular Ca2+concentration.Subsequently,MAPK signaling was suppressed,resulting in the inhibition of CRC cell growth.Consistently,terbinafine,an SQLE inhibitor,suppressed CRC cell proliferation and organoid and xenograft tumor growth.Conclusions:Our findings demonstrate that SQLE promotes CRC through the accumulation of calcitriol and stimulation of CYP24A1-mediated MAPK signaling,highlighting SQLE as a potential therapeutic target for CRC treatment.

龙牙楤木SE基因克隆与植物表达载体构建

采用RT-PCR的方法,从龙牙楤木中克隆到鲨烯环氧酶(SE)基因,该基因的cDNA全长为1 682 bp,含有1 644 bp的开放阅读框(ORF),编码547个氨基酸,将所得的序列提交GenBank数据库,登录号为GU354314。序列分析结果表明:龙牙楤木SE基因的氨基酸序列与人参、三七、绞股蓝的同源性>90%,并构建了该基因的植物表达载体pAeSE。

基于转录组测序的兔儿伞羽扇豆醇合成途径及关键酶基因研究

为解析兔儿伞羽扇豆醇生物合成途径,探究其关键酶基因,研究运用DNBSEQ测序平台对兔儿伞的叶、茎、根及根茎进行转录组测序,从头组装后获得了191541条Unigenes。KEGG代谢通路分析表明有961条Unigenes涉及兔儿伞羽扇豆醇生物合成途径,其中,395条Unigenes编码羽扇豆醇生物合成途径的17个关键酶。根与其他各组织比较,24条共有差异表达基因涉及羽扇豆醇生物合成途径,编码了法尼基焦磷酸合酶(farnesyl diphosphate synthase,FPPS)、角鲨烯合成酶(squalene synthase,SS)、角鲨烯环氧酶(squalene epoxidase,SE)等关键酶。对关键酶FPPS、SS和SE进行结构分析,发现它们均具有保守的催化结构域和底物结合结构域。研究丰富了兔儿伞植物的功能基因数据库,为进一步研究羽扇豆醇生物合成途径及其关键酶基因的功能和调控机制奠定了基础。

SQLE敲除促进黑色素瘤肿瘤微环境CD8+T细胞浸润发挥抗肿瘤效应

目的探讨黑色素瘤细胞鲨烯环氧合酶(SQLE)基因敲除调控肿瘤微环境T细胞浸润影响机体抗肿瘤效应的作用及其分子机制。方法使用SQLE敲除的B16F10细胞系分别接种免疫完全和免疫缺陷小鼠,明确基因敲除对肿瘤细胞恶性表型的自主和非自主性调控,进一步使用抗体阻断、Luminex多因子检测和流式细胞等技术探索SQLE基因敲除对细胞因子/趋化因子分泌及免疫浸润的影响,结合生物信息学分析,验证SQLE表达与免疫浸润和临床预后的相关性。结果与免疫缺陷型小鼠相比,敲除SQLE显著抑制免疫完全小鼠肿瘤增殖,延长小鼠生存期。SQLE敲除诱导肿瘤细胞分泌细胞因子和趋化因子,增加肿瘤微环境CD8+T细胞浸润从而改善机体抗肿瘤效应。生物信息学分析提示SQLE及其对应的免疫浸润标志物与黑色素瘤患者临床预后明显相关。结论SQLE通过细胞因子和趋化因子调控肿瘤微环境参与机体抗肿瘤效应,有望成为新的肿瘤免疫药物靶点和疗效预测分子指标。

直肠癌组织中LncRNA TTN-AS1及角鲨烯环氧酶表达与临床病理特征及预后相关性研究

目的研究直肠癌组织中长链非编码RNA(long non-coding RNA,LncRNA)TTN-AS1和角鲨烯环氧酶(squalene epoxidase,SQLE)的表达与临床病理特征及预后相关性。方法选取2018年1月~2020年1月成都中医药大学附属医院诊治的90例直肠癌患者为研究对象。采用荧光定量PCR检测组织LncRNA TTN-AS1表达。采用免疫组织化学法检测组织SQLE表达。分析LncTTN-AS1,SQLE与直肠癌临床病理特征的关系。KM曲线分析LncRNA TTNAS1,SQLE对直肠癌预后的影响。COX回归分析影响直肠癌预后的因素。结果直肠癌组织中LncRNA TTN-AS1(3.12±0.45)相对表达量,SQLE(71.11%)蛋白阳性率均高于癌旁组织(0.91±0.12,8.89%),差异具有统计学意义(t/χ^(2)=45.156,72.593,均P<0.001)。直肠癌组织中LncRNA TTN-AS1与SQLE表达呈正相关(r=0.589,P<0.001)。TNM分期Ⅲ期、淋巴结转移癌组织中Lnc RNA TTN-AS1相对表达量(4.26±0.52,4.10±0.49)、SQLE(88.57%,91.43%)阳性率高于TNM分期Ⅰ~Ⅱ期(2.39±0.40,60.00%)、无淋巴结转移癌组织(2.50±0.42,58.18%),差异具有统计学意义(t/χ^(2)=8.409~19.211,均P<0.05)。LncRNA TTN-AS1高表达组和低表达组三年生存率分别为50.00%(22/44)和86.96%(40/46),差异具有统计学意义(Log-rankχ^(2)=14.205,P=0.001)。SQLE阳性组和阴性组三年生存率分别为64.06%(41/64)和88.46%(23/26),差异具有统计学意义(Log-rankχ^(2)=6.291,P=0.012)。LncRNATTNAS1高表达(HR=2.552,P=0.001)、SQLE阳性(HR=1.754,P=0.004)、TNM分期Ⅲ期(HR=2.797,P=0.011)和淋巴结转移(HR=1.635,P=0.030)是直肠癌预后的独立危险因素。结论直肠癌组织中LncRNA TTN-AS1,SQLE表达升高,与直肠癌肿瘤TNM分期及淋巴结转移有关,是评估直肠癌预后的肿瘤标志物。

人参SE基因RNAi载体的构建及转化

在克隆人参鲨烯环氧酶基因保守区约364 bp片段基础上,构建该基因的RNAi植物双元表达载体pMHZ111-SE,并利用农杆菌介导的遗传转化方法转化人参愈伤组织,通过HPLC方法测定转基因和非转基因人参愈伤组织中6种单体皂苷的含量。结果表明,经干扰载体转化的人参愈伤组织中Rg1、Re、Rc单体皂苷含量均有大幅度下降,其他3种皂苷含量变化不明显。

玉米SEs基因家族生物信息学分析

为获悉玉米SEs基因家族的功能和系统进化关系,利用生物信息学方法对玉米SEs基因家族进行鉴定,同时分析其家族成员理化性质、蛋白质二级结构、进化关系、基因结构、保守结构、氨基酸序列、染色体及启动子顺式作用元件。结果表明,在玉米中共鉴定到10个SEs基因家族成员,编码蛋白质的氨基酸序列长度为320~534 aa,分子量大小为33.85~56.94 kDa,等电点为6.57~9.15;亚细胞定位预测结果表明大部分玉米SEs蛋白定位在细胞质和原生质;系统进化树将玉米SEs基因家族分为3支;基因结构的保守基序分析说明玉米SEs基因家族存在一定的差异性;10个玉米SEs基因家族成员主要分布在Chr1、Chr5和Chr9上;氨基酸多序列比对分析表明10个玉米SEs基因家族成员存在一定的结构相似性;蛋白序列中存在10种Motif;启动子顺式作用元件分析表明玉米SEs基因主要受光响应、茉莉酸信号响应调控。

Mycorrhizas Affect Polyphyllin Accumulation of Paris polyphylla var.yunnanensis through Promoting PpSE Expression

Paris polyphylla var.yunnanensis is a traditional Chinese medicinal plant,in which polyphyllin as the main medicinal component is an important secondary metabolite with bioactivity.Arbuscular mycorrhizal fungi(AMF)have multiple positive effects on plants,while it is not clear whether AMF increase the content of medicinal components in medicinal plants.In this study,a total of nine AMF treatments were laid to analyze the mycorrhizal effect on polyphyllin accumulation and PpHMGR and PpSE expression of P.polyphylla var.yunnanensis.AMF increased the content of polyphyllin in the cultivated variety with low relation to the increase of inoculation intensity.Polyphyllin I,II,and VII were identified and partly improved by AMF inoculation,dependent on AMF treatments and culture environments.Similarly,the PpHMGR and PpSE expression was induced by mycorrhization,dependent on AMF species,whilst the induction was more obvious in PpSE than in PpHMGR after mycorrhization.It concluded that the symbiotic relationship between P.polyphylla var.yunnanensis and AMF increased polyphyllin content level in the plant,which was associated with the up-regulation of PpSE transcripts.

角鲨烯环氧化酶通过调控AKT/mTOR信号通路促进卵巢癌细胞的糖代谢

目的研究角鲨烯环氧化酶(squalene epoxidase,SQLE)在卵巢癌中的作用机制。方法收集50例新鲜卵巢癌及癌旁正常组织,免疫组化检测两组SQLE表达差异。同时,蛋白印迹实验(Western Blot,WB)检测SQLE在卵巢癌细胞系中的表达情况。通过克隆形成实验及流式细胞仪实验检测对卵巢癌细胞增殖、凋亡的影响。通过WB研究SQLE对卵巢癌的作用机制。结果SQLE在卵巢癌组织及癌细胞系中相比于正常组织或上皮细胞表达水平显著上升。克隆形成实验结果显示,敲减SQLE表达后,卵巢癌细胞增殖能力受到抑制。流式细胞仪实验结果显示,敲减SQLE表达后,促进了卵巢癌凋亡。WB实验结果显示,在抑制SQLE表达后,沃伯格效应关键蛋白GLUT1、LDH表达显著下降,葡萄糖消耗水平、乳酸水平和ATP水平显著降低。对蛋白激酶B/哺乳动物雷帕霉素靶点(protein kinase B/mammalian target of rapamycin,AKT/mTOR)信号通路关键蛋白检测,发现下调SQLE表达后,p-AKT、p-mTOR蛋白水平明显下降。结论SQLE在卵巢癌中高表达,并且可能通过AKT/mTOR信号通路促进卵巢癌细胞的糖代谢并且抑制细胞凋亡。

绞股蓝鲨烯环氧酶基因的克隆与序列分析

根据已报道植物鲨烯环氧酶（squalene epoxidase,SE）基因cDNA序列的保守区域设计引物,利用RT-PCR和RACE技术,对绞股蓝SE基因进行克隆及序列分析.结果表明,绞股蓝SE基因cDNA全长为1 818 bp,编码一个由525个氨基酸残基组成的多肽.绞股蓝SE基因编码的氨基酸序列中含有52.4%的非极性疏水性氨基酸,26.1%极性中性氨基酸,9.0%酸性氨基酸,12.6%碱性氨基酸.Blast结果显示,绞股蓝SE基因核苷酸序列与其他已报道的植物SE基因相似性为73%～82%,推导的氨基酸序列相似性为63.2%～79.4%.SE氨基酸序列进化分析发现,绞股蓝SE与绿珊瑚、拟南芥亲缘关系较近.

鲨烯环氧酶基因的克隆及其在人参根组织中的表达

对人参根组织中的鲨烯环氧酶基因进行了克隆与序列分析,并利用相对荧光定量Real-time PCR法检测了鲨烯环氧酶基因不同年生人参根组织中的表达水平。结果表明:克隆人参根中鲨烯环氧酶基因全长编码区cDNA为1 611 bp,编码537aa长的多肽,其核苷酸和氨基酸序列与GenBank中人参鲨烯环氧酶基因序列(登录号:AB122078.1)对比,同源性分别为99.75%和99.81%。相对荧光定量PCR差异分析发现鲨烯环氧酶基因在一年、三年、四年、五年生人参根组织中均有表达,其中在五年生人参根中表达水平最高。

人参鲨烯环氧酶基因的克隆与原核表达

【目的】克隆人参皂苷生物合成途径中的鲨烯环氧酶(SQE)基因,并进行原核表达与纯化,初步探讨SQE活性与人参皂苷生成量之间的关系。【方法】以4年生人参根组织须根为材料,提取其总RNA,反转录为cD-NA。以合成的cDNA为模板,对SQE基因进行克隆,再将其插入原核表达载体pET-30a中,构建pET-30a-SQE重组质粒,经酶切和测序鉴定后,转入Rosetta大肠杆菌,经0.8mmol/L IPTG 37℃诱导表达4h后,进行SDS-PAGE电泳检测,采用Ni-Agarose亲和层析柱纯化目的蛋白,利用液相色谱-串联质谱联用技术(LC-MS)检测SQE的活性。【结果】获得了人参SQE基因1 611bp的全长编码区cDNA。酶切和测序结果表明,原核表达载体pET-30a-SQE构建成功;SDS-PAGE分析显示,在Rosetta大肠杆菌中成功诱导表达了SQE融合蛋白,且纯化后的目的蛋白纯度较高;LC-MS联用检测结果发现,随着SQE用量的增加,达玛烯二醇的生成量递增。【结论】克隆了人参SQE基因,获得了在体外具有生物学活性的SQE蛋白,并证实了其活性与人参皂苷生成量有很大的相关性。

植物甾醇与三萜类皂苷生物合成基因调控的研究进展

植物甾醇和三萜类皂苷是2种具有调节生物体系免疫力,抗血糖过多,抗癌症等生理功能的植物次生代谢产物。它们在生物合成过程中有许多关键酶,如鲨烯合成酶(SS)、鲨烯氧化酶(SE)、氧化鲨烯环化酶(OSCs)和糖基转移酶(GT)等。综述了这些关键酶在催化机理、基因克隆与表达调控方面的研究进展,并简要探讨了通过这些关键酶的代谢工程研究来增产植物甾醇和三萜类皂苷的广阔前景。

紫花苜蓿MsSQE1的克隆及对皂甙合成的功能分析

【目的】鲨烯环氧酶(squalene epoxidases,SQE)是苜蓿皂甙合成途径中的一种限速酶,与苜蓿皂甙的合成密切相关。通过对苜蓿鲨烯环氧酶(MsSQE1)基因的克隆及在苜蓿中过表达,探究鲨烯环氧酶对皂甙合成的作用机制。【方法】以模式植物蒺藜苜蓿鲨烯环氧酶基因序列设计引物,同源克隆苜蓿MsSQE1。对MsSQE1进行生物信息学分析;通过基因枪轰击技术,使MsSQE1在洋葱表皮瞬时表达,进行亚细胞定位。利用qRT-PCR方法分析该基因在根、茎、叶中的表达水平,以及在紫外辐射、ABA和GA3条件下的表达模式。在茉莉酸甲酯(MeJA)的诱导下,分析MsSQE1的转录水平,及对苜蓿皂甙含量的影响。利用根癌农杆菌转化体系,获得过表达MsSQE1的阳性转基因植株,并测定转基因植株的皂甙含量。【结果】克隆了MsSQE1的cDNA序列,开放阅读框1 578 bp,编码525个氨基酸,等电点为8.59。同源性比对分析,其氨基酸序列与蒺藜苜蓿中SQE1氨基酸序列同源性为98.6%,与拟南芥的同源性为80%。亚细胞定位显示,MsSQE1可能定位于细胞膜。组织特异性表达分析显示,MsSQE1在叶中的表达量最高,茎中次之,根中的表达量最低。在紫外辐射、ABA和GA3的诱导表达显示,紫外辐射诱导24 h,叶中表达量最高;GA3(50μmol·L^-1)和ABA(100μmol·L^-1)处理,均为8 h叶中表达量最高;MeJA处理能诱导MsSQE1表达量上调的同时苜蓿总皂甙含量也随着MsSQE1表达的上调而增加。分析过表达MsSQE1转基因苜蓿和转空载体苜蓿株系发现,MsSQE1的表达水平和总皂甙含量均升高,其中MsSQE1的表达水平是对照的3.11-9.45倍,总皂甙含量比对照提高14.26%-28.05%,暗示MsSQE1是苜蓿皂甙合成途径中的一种关键调节酶。【结论】从豆科牧草紫花苜蓿中克隆了MsSQE1并进行功能分析。在苜蓿中过表达MsSQE1能增加苜蓿总皂甙含量,暗示MsSQE1的表达影响苜蓿皂甙的生物合成,可能对皂甙的合成有重要的调节作用。

中药三萜皂苷合成通路的生物信息学分析

目的从系统进化学角度对中药三萜皂苷合成通路中关键酶进行生物信息学分析。方法从NCBI数据库下载已有17种中药中的鲨烯合成酶、鲨烯环氧酶、2,3-氧化鲨烯环化酶的蛋白质全长序列,通过生物信息学软件对其进行理化性质分析、保守域分析、蛋白质三维结构预测和系统进化树的构建。结果序列分析表明,鲨烯合成酶、鲨烯环氧酶、2,3-氧化鲨烯环化酶的蛋白质序列保守性均较高。其中鲨烯合成酶具有两个高度保守的区域——富含天冬氨酸的镁离子结合位点1和2——可作为认定鲨烯合成酶的依据;鲨烯环氧酶和2,3-氧化鲨烯环化酶的蛋白三维结构保守,无规则卷曲部分为高变区。结论上游合成在进化中趋于保守和稳定;三萜皂苷众多类型的形成可能与下游细胞色素P450、糖基转移酶、β-糖苷酶等的修饰有关。