猫爪草提取物对临床分离结核分枝杆菌蛋白质组表达的影响

猫爪草已经临床治疗耐药结核病,但其作用机理和有效成分尚不清楚。为研究其可能的作用靶标,采用双向电泳技术比较分析猫爪草提取物作用前后结核分枝杆菌临床分离株的全细胞蛋白表达差异。发现22个蛋白质斑点具有明显差异,对其中3个表达明显下调的蛋白质斑点进行基质辅助激光解吸电离飞行时间质谱分析,获得了肽质量指纹图谱。数据库检索分析确定这3个点代表的蛋白质分别为硫代硫酸硫转移酶,延长因子Ts和热休克蛋白X,分别参与厌氧硫代谢、蛋白质翻译和蛋白质折叠分泌、转录调控等过程。这有助于深入研究猫爪草对结核分枝杆菌的作用机理,也为发现新的抗结核病治疗药物靶标提供了线索。     

异烟肼耐药结核分枝杆菌感染人源巨噬细胞的蛋白质组学研究

利用双向电泳技术,对人源巨噬细胞U937感染异烟肼耐药结核分枝杆菌前后的全细胞蛋白表达图谱进行差异比较和分析,发现其中产生差异的有32个蛋白质斑点,利用基质辅助激光解吸/电离飞行时间质谱技术,对其中5个表达明显上调的蛋白质斑点进行分析鉴定,获得5个明确的肽质量指纹图谱,通过在数据库中进行检索分析,确定这5个蛋白质分别为热休克蛋白105_β、凋亡抑制蛋白-1、磷酸甘油酸变位酶1、组织蛋白酶B、桥粒胶蛋白3.上述发现有助于了解耐药结核分枝杆菌入侵早期导致的巨噬细胞蛋白质组表达变化,为深入研究耐药结核分枝杆菌-宿主相互作用提供了探索方向.     

结核分枝杆菌感染人源树突状细胞的蛋白质表达谱

在结核分枝杆菌(Mycobacteriumtuberculosis,MTB)的感染中,树突状细胞(Dendriticcells ,DCs)的应答反应是机体起始免疫应答的关键。因此,利用双向电泳技术(Two_dimensionalelectrophoresis,2_DE)对人源树突状细胞受结核分枝杆菌H37RvATCC 2 72 94菌株感染前后的全细胞蛋白表达图谱进行差异比较和分析,发现其中产生差异的有4 5个蛋白质斑点,利用基质辅助激光解析电离串联飞行时间质谱技术对其中4个表达明显上调的蛋白质斑点进行分析鉴定,获得4个明确的肽指纹图谱,通过在数据库中检索分析,确定这4个蛋白质分别为人亚砷酸诱导ATP酶I(HumanArsenite_stimulatedATPase ,hASNA_I) ,膜联蛋白IV(AnnexinIV) ,γ_肌动蛋白(γ_actin) ,热休克蛋白2 7(Heatshockprotein2 7,HSP2 7)。上述发现有助于了解结核分枝杆菌入侵早期导致的树突状细胞蛋白质组表达变化,为深入研究结核分枝杆菌 宿主相互作用提供了探索方向     

氨基酰-tRNA合成酶与神经退行性疾病

氨基酰-tRNA合成酶催化tRNA的氨基酰化反应为生物体内的蛋白质合成提供原料.这类古老且保守的蛋白质分子在高等生物复杂的细胞分子网络中分化出的新功能是目前人们关注的焦点.近期在对一些患有神经退行性疾病的病人和小鼠模型的研究中发现,位于酪氨酰-tRNA合成酶、甘氨酰-tRNA合成酶和丙氨酰-tRNA合成酶上的突变,可分别导致DI腓骨肌萎缩症(Charcot-Marie-Toothdisease,CMT)C型,腓骨肌萎缩症2D型及小脑浦肯雅(Purkinje)细胞丢失.初步的致病机理研究表明,致病突变对这3种酶的影响各不相同:酪氨酰-tRNA合成酶的氨基酰化催化能力受到影响,甘氨酰-tRNA合成酶受影响的可能是一种未知的新功能,而丙氨酰-tRNA合成酶受影响的则是它的编校功能.这些研究结果揭示了氨基酰-tRNA合成酶涉及神经退行性疾病的广泛性和其机制的复杂性,并将促进对神经退行性疾病这一类常见疾病的病理和治疗方法的研究.     

氨酰tRNA合成酶的分子网络和功能

氨酰tRNA合成酶是生命进化过程中最早出现的一类蛋白质,氨酰tRNA合成酶帮助氨基酸转移到相应的tRNA上,进而参与蛋白质的合成保证了生命体的严谨性和多样性.随着后基因组时代的到来,氨酰tRNA合成酶的结构和功能成为新的研究热点.结构生物学和生物信息学的研究结果表明,氨酰tRNA合成酶在真核生物体内以多聚复合物的形式行使功能,形成复杂的分子网络体系.最新的实验证据显示,氨酰tRNA合成酶不但是蛋白质合成过程中一类最重要的酶,而且参与了转录、翻译水平的调控、RNA剪接、信号传导和免疫应答等众多生命活动.     

一种新型抗结核先导化合物S28 对结核分枝杆菌蛋白质组表达的影响

目的 探讨从化合物库中高通量筛选得到的、可有效抑制结核分枝杆菌生长和繁殖的新型活性化合物S28 的作用机制及其可能的作用靶点。方法 采用双向电泳技术, 比较分析活性化合物作用于结核分枝杆菌H37Ra 前、后的全细胞蛋白表达差异。结果 13 个蛋白质斑点表达下调, 对其中6 个改变明显的蛋白质斑点进行基质辅助激光解吸/ 电离飞行时间质谱分析, 成功测定2 个蛋白质斑点。数据库检索分析确定这2 个差异蛋白点分别为延长因子Tu 和短链脱氢酶, 是参与蛋白质翻译和氧化呼吸、能量代谢等生理过程的重要蛋白。结论 为 进一步深入探索新型抗结核活性化合物的作用机制和可能的靶点提供研究基础和方向。     

两种具有调节血管生成作用的氨基酰-tRNA合成酶

氨基酰-tRNA合成酶是生物体内蛋白质合成过程中的一类关键酶,它催化体内tRNA的氨基酰化反应.作为一类古老的蛋白质,氨基酰-tRNA合成酶在其漫长的进化过程中,通过其他结构域的插入或融合逐渐演化出许多新的功能.最近的研究结果表明,人酪氨酰-tRNA合成酶的片段具有促进血管生成的功能,而人色氨酰-tRNA合成酶的片段则具有抑制血管生长的功能.在哺乳动物细胞中,蛋白质的生物合成途径与细胞信号转导途径紧密相连.今后,随着对氨基酰-tRNA合成酶研究的不断深入,可以通过它们与细胞因子和信号转导相连的功能治疗人类的疾病.     

五个3-酮脂酰ACP合成酶同源蛋白的功能鉴定

大肠杆菌的FabB和FabF均具有长链3-酮基脂酰ACP合成酶活性.除参与长链饱和脂酰链的延伸外,FabB还是合成不饱和脂肪酸的关键酶之一,参与不饱和脂酰ACP的从头合成,最终生成顺-9-十六烯脂酰ACP.而FabF只能将顺-9-十六烯脂酰ACP延伸为顺-11-十八烯脂酰ACP,不参与不饱和脂酰ACP的从头合成.有研究表明,粪肠球菌、乳酸乳球菌、丙酮丁醇梭菌和茄科雷尔氏菌等细菌的FabF同源蛋白,具有类似大肠杆菌FabB和FabF的双功能.为证实该现象是否普遍存在,本研究选取了枯草芽孢杆菌BsfabF、中华苜蓿根瘤菌SmfabF、霍乱弧菌VcfabF、铜绿假单胞菌PafabF1和PafabF2 5个同源基因进行功能鉴定,体外酶学分析表明,5个FabF同源蛋白均具有长链3-酮基脂酰ACP合成酶活性,异体互补大肠杆菌CL28的脂肪酸组分分析显示,SmfabF、VcfabF、PafabF1和PafabF2具有3-酮脂酰ACP合成酶Ⅱ(FabF)活性,遗传互补大肠杆菌温度敏感突变株CY242和CY244的研究显示,仅有PafabF2编码的蛋白拥有3-酮脂酰ACP合成酶Ⅰ(FabB)活性,能互补大肠杆菌fabB的突变.这表明不是所有的FabF同源蛋白均具有3-酮脂酰ACP合成酶Ⅰ和Ⅱ的双重活性.     

柔嫩艾美耳球虫地克株利抗药株与敏感株孢子化卵囊的蛋白质差异分析

利用双向电泳技术,对本实验室诱导保存的柔嫩艾美耳球虫地克株利抗药株与敏感株的蛋白质表达图谱进行差异比较和分析,发现两者之间差异有5个蛋白质斑点,利用MALDI_TOF_TOF质谱技术对其中4个差异明显的蛋白质斑点进行分析鉴定,获得4个明确的肽质量指纹图谱,通过在NCBInr数据库中检索分析,确定了其中2个蛋白质分别为球虫子孢子表面抗原TA4和热休克蛋白Hsp70 ,另外两种为真核细胞的功能蛋白。上述蛋白的鉴定将对球虫的抗药性产生机理和柔嫩艾美耳球虫地克株利抗药株的分子标志物提供了研究方向。     

利用双向电泳技术研究异烟肼耐药MTB感染U937引致的差异表达蛋白

利用双向电泳技术对结核分枝杆菌（MTB）异烟肼（INH）耐药株和敏感株感染人源巨 噬细胞（U937）后的全细胞蛋白表达图谱进行差异比较和分析,发现其中产生差异的有86个蛋白质斑点.利用基质辅助激光解吸/电离飞行时间质谱技术对其中8个差异表达蛋白质斑点进行分析鉴定,获得8个明确的肽质量指纹图谱.通过在蛋白质数据库中进行检索分析,确定这8个蛋白质中的2个为在INH耐药株感染的U937中差异表达的干细胞生长因子和主要组织相容性复合物Ⅰ类抗原,6个为在敏感株感染的U937中差异表达的微管蛋白β4、信号转导和转录激活子3、延长因子-2激酶、环指蛋白29、锌指蛋白193和SNARE Vti1a-β蛋白.实验结果显示,INH耐药株和敏感株感染后的U937表达蛋白有差异,这有助于分析解释临床中观察到的受INH耐药株感染的病例出现毒力下降、致病性下降、传染性降低以及潜伏期延长的现象.结果为针对INH耐药株进行的新疫苗的设计提供了探索方向.     

Comparative proteome analysis of culture supernatant proteins of Mycobacterium tuberculosis H37Rv and H37Ra

To examine the virulence factors of Mycobacterium tuberculosis H37Rv, the proteome was used to characterize the differences in protein expression between virulent M. tuberculosis H37Rv and attenuated M. tuberculosis H37Ra. Two-dimensional gel electrophoresis was performed to separate culture supernatant proteins extracted from M. tuberculosis H37Rv and M. tuberculosis H37Ra. The protein spots of interest were identified by mass spectrometry, and then the genes encoding the identified proteins were cloned and sequenced. Comparison of silver-stained gels showed that three well-resolved protein spots were present in M. tuberculosis H37Rv but absent from M. tuberculosis H37Ra. Protein spot no. 1 was identified as Rv2346c. Protein spot no. 2 was identified as Rv2347c, Rv1197, Rv1038c, and Rv3620c, which shared significant homology and had the same peptide fingerprinting using tryptic digestion. No M. tuberculosis protein matched protein spot no. 3. Rv2346c, Rv2347c, Rv1038c, and Rv3620c of M. tuberculosis H37Rv were located on the M. tuberculosis H37Ra chromosome, and multiple mutations were observed in the corresponding areas of M. tuberculosis H37Ra. Codon 59 (CAG, Gln) of Rv2347c and Rv3620c was replaced by termination codon (TAG) in M. tuberculosis H37Ra, which probably terminated the polypeptide elongation. These results demonstrate the importance of studying the gene products of M. tuberculosis and show that subtle differences in isogenic mutant strains might play an important role in identifying the attenuating mutations.     

Domain analysis of fatty acid synthase protein (NP_217040) from Mycobacterium tuberculosis H37Rv--a bioinformatics study

Different domains of fatty acid synthase (FAS) protein of Mycobacterium tuberculosis H37Rv, involved in mycolic acid synthesis were analyzed using various bioinformatics tools. Based on different database searches (CDD and Pfam), FAS protein of Mycobacterium tuberculosis was grouped into eight domains, five of which showed close similarity with pdb templates (1MLA, 1IQ6A, 2BMOA, and 1J3NA). Based on the PSI blast analysis, 3D structures of only five domains were predicted using MODELLER software, and loop modeling was done for only those regions that were predicted as loops by predict protein server. Compared to the original structure, the loop modeled structure showed a lower DOPE score value for FAS protein. The X-ray determined templates that were used for predicting the 3D structure suggest that, FAS protein has "Malonyl-coenzyme A-Hydratase-Nitrobenzene dioxygenase-3-oxoacyl-(acp) synthase" activity. Accuracy of the prediction of 3D structure of different domains of FAS protein was further validated by Ramachandran plot and PROCHECK (G-value).     

Proteomic analysis of near-isogenic sunflower varieties differing in seed oil traits

Near-isogenic sunflower lines containing 25% (inbred RHA280) and 48% (RHA801) oil by seed dry mass were comparatively analyzed in biological triplicate at 18 days after flowering using two-dimensional (both pI 3-10 and 4-7) Difference Gel Electrophoresis. Additionally, two inbred lines varying in oleic acid content, HA89 (18% oleic) and HA341 (89% oleic), were also analyzed in the same manner. Statistical analyses of these sunflower lines was performed beginning with fitting a mixed effects linear model to the log-transformed optical volume of each spot to account for gel variation, followed by testing the significance between varieties for mean transformed optical spot volumes. The p-values from the spot analysis procedures were then used to find the cutoff point for differential expression using a 10% false-discovery rate (FDR). Comparison of the oil content and oleic acid composition lines revealed 77 and 42 protein spots below the 10% FDR cutoff, respectively, and were therefore declared differentially expressed. Liquid chromatography-tandem mass spectrometry analysis of each of these protein spots resulted in assignments for 44 and 17 spots, respectively. Fructokinase, plastid phosphoglycerate kinase, and enolase proteins were determined to be up-regulated in the high oil line, while phosphofructokinase, cytosolic phosphoglucomutase, and cytsolic phosphoglycerate kinase were up-regulated in the low oil variety. Additionally, four activities involved in amino acid synthesis were up-regulated in the low oil variety in addition to 12S storage proteins and a protein similar to legumin storage protein. Interestingly, two 2-DE spots identified as 14-3-3 proteins were found to be up-regulated in high oleic acid variety. Alteration of glycolytic and amino acid biosynthetic enzymes, as well as storage protein levels, suggests seed oil content is tightly linked to carbohydrate metabolism and protein synthesis in a complex manner.     

Assessment of protein spot components applying correspondence analysis for peptide mass fingerprint data

Proteins separated by two-dimensional gel electrophoresis (2-DE) may be distributed over several spots. Otherwise, one spot may contain more than one component. The same protein occurring in several spots supposedly represents differently modified protein species that might be of biological relevance. Identification of spots with peptide mass fingerprinting and database searching leads only to the detection of the major spot components. If a spot also contains additional minor protein components, quantitation of spots with protein staining techniques or antibody detection becomes misleading. In order to find spots containing minor components we applied correspondence analysis, a multivariate data exploration method, to peptide mass fingerprint data. Correspondence analysis using peak lists revealed groups of spots containing the same protein with their characteristic mass-to-charge ratio (m/z) values. In order to detect different protein spot components an interactive threshold setting and removal of m/z values with subsequent recalculation of the correspondence analysis using our software tool CorrAn are performed. The usefulness of this methodical approach was shown by a data set of peptide mass fingerprints of 284 spots of Helicobacter pylori 26695 separated by 2-DE.     

A proteomics study of in vitro cyst germination and appressoria formation in Phytophthora infestans

A proteomics study using two-dimensional gel electrophoresis (2-DE) and mass spectrometry was performed on Phytophthora infestans. Proteins from cysts, germinated cysts and appressoria grown in vitro were isolated and separated by 2-DE. Statistical quantitative analysis of the protein spots from five independent experiments of each developmental stage revealed significant up-regulation of ten spots on gels from germinated cysts compared to cysts. Five spots were significantly up-regulated on gels from appressoria compared to germinated cysts and one of these up-regulated spots was not detectable on gels from cysts. In addition, one spot was significantly down-regulated and another spot not detectable on the gels from appressoria. The corresponding proteins to 13 of these spots were identified with high confidence using tandem mass spectrometry and database searches. The functions of the proteins that were up-regulated in germinated cysts and appressoria can be grouped into the following categories: protein synthesis (e.g. a DEAD box RNA helicase), amino acid metabolism, energy metabolism and reactive oxygen species scavenging. The spot not detected in appressoria was identified as the P. infestans crinkling- and necrosis-inducing protein CRN2. The identified proteins are most likely involved in the establishment of the infection of the host plant.     

微管解聚剂和光合作用抑制型除草剂诱导的黑麦和玉米中蛋白质组分变化的比较研究

研究了黑麦、玉米在经甲基胺草膦和Atrazine两种除草剂处理后叶绿素含量、叶绿体和根尖分生组织内的蛋白质组份变化,实验结果表明,0.1 mg·L^-1的Atrazine可使黑麦中的叶绿素含量下降（分别从对照的1.72±0.034 mg·g^-1 FW下降到1.62±0.05 mg·g^-1 FW、1.25±0.015 mg·g^-1 FW）。2种除草剂均可使黑麦、玉米中的蛋白质组份产生改变,如当分别用0.1 mg·L^-1的Atrazine处理时,黑麦分生组织中,有4个蛋白质斑点,斑点7、斑点18~20被诱导产生,12个蛋白质斑点,斑点6、斑点8~17、斑点21消失。玉米分生组织中,有4个蛋白质斑点,斑点5、斑点14~16被诱导产生,4个蛋白质斑点,斑点17~20消失。黑麦叶绿体中,有两个蛋白质斑点被诱导产生,13个蛋白质斑点,斑点1~13消失,但Atrazine处理不引起玉米叶绿素含量和叶绿体蛋白质组份的变化。4 mg·L^-1 APM可引起黑麦和玉米分生组织蛋白质组份变化,在黑麦中,1个蛋白质斑点被诱导产生,4个蛋白质斑点,斑点2~5消失。玉米分生组织中,15个蛋白质斑点,斑点4~5、斑点7~16、斑点21~23被诱导产生,4个蛋白质斑点,斑点1~3、斑点6消失。APM均不能引起2种作物中叶绿素含量和叶绿体蛋白质组份的变化。