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91.
利用离子交换色谱SP-5PW和疏水色谱POROS HP2从板蓝根鲜根水相抽提物中分离纯化多肽组分,并对其进行生化表征.获得一种达到电泳纯的多肽RIP2,其相对分子质量约为6.87 ku,等电点约为7.73,N端氨基酸序列依次为QIGEFATAPF.经数据库搜索比对,发现该多肽与核黄素合酶α亚基具有一定的同源性.细胞毒性实验表明该多肽具有一定抗病毒作用. 相似文献
92.
韩长志 《信阳师范学院学报(自然科学版)》2015,(1):53-58
基于前人对禾谷炭疽菌中已报道的177个候选效应分子的氨基酸数据,结合其他已报道效应分子具有的5个典型特征,通过信号肽预测、跨膜区结构预测以及氨基酸基本特征、半胱氨酸含量等分析,明确82个候选效应分子具有效应分子的典型特征;同时,利用SMART在线分析工具,明确上述效应分子具有高度序列特异性特点. 相似文献
93.
以L-组氨酸为起始原料,设计合成了含组氨酸残基的手性肽核酸单体.以叔丁氧羰基(Boc)保护α-氨基,羧基形成苄酯加以保护,分别以苄氧羰基(Cbz)及2,4-二硝基苯基(Dnp)作为咪唑基的临时和永久保护基,共九步反应,手性肽核酸单体总收率13.3%. 相似文献
94.
The molecular recognition hypothesis for peptides is that binding sites of ligands and their receptors are encoded by short,
complementary segments of DNA. A corollary hypothesis for nonpeptide ligands posited here is that peptide replicas may be
encoded by the DNA segment complementary to the receptor binding sites for nonpeptides. This corollary was tested for digitalis,
a family of cardiotonic and natriuretic steroids including ouabain. A hexapeptide (ouabain-like peptide, OLP) complementary
to a ouabain binding site on sodium/potassium dependent adenosine triphosphatase (Na+ K+ ATPase) exhibited activity in a digitalis bioassay. Antisera to the complementary peptide (OLP) stained the neurohypophysis
in an immunocytochemical procedure. The complementary peptide was found to share an identical 4-amino acid region with the
39-amino acid glycopeptide moiety of the vasopressin-neurophysin precursor. This glycopeptide was isolated from pituitary
extracts; it exhibited digitalis-like activity in the submicromolar range and cross-reacted with complementary peptide antibodies.
Another digitalis-like substance with high activity also was detected in the extracts. These results demonstrate that the
vasopressin-neurophysin glycopeptide has digitalis-like activity. Moreover, the findings are consistent with the hypothesis
that peptide mimetics of nonpeptides are encoded in the genome.
Received 23 November 1998; received after revision 18 January 1999; accepted 19 February 1999 相似文献
95.
Ruchaud-Sparagano MH Westley BR May FE 《Cellular and molecular life sciences : CMLS》2004,61(15):1946-1954
The trefoil protein TFF1 is expressed principally in the superficial cells of the gastric mucosa. It is a
small protein and forms homo- and hetero-dimers via a disulphide bond through Cys58 which is located three amino
acids from the C terminus. TFF1 is co-expressed with the secreted mucin MUC5AC in superficial cells of the gastric
mucosa suggesting that it could be involved in the packaging or function of gastric mucus. We have previously
shown that TFF1 co-sediments with mucin glycoproteins on caesium chloride gradients. To extend this observation
we have now used gel filtration under physiological conditions, immunoprecipitation and Western transfer analysis
to characterise the interaction of TFF1 with gastric mucin glycoproteins. We show that TFF1 co-elutes with MUC5AC
but not MUC6 on gel filtration and that immunoprecipitation and Western transfer analysis confirms that TFF1
interacts with MUC5AC. We also demonstrate that the TFF1 dimer is the predominant molecular form bound to MUC5AC.
Salt and chelators of divalent cations such as EDTA and EGTA disrupted the TFF1- MUC5AC interaction and increased
the degradation of MUC5AC, whereas calcium increased the amount of TFF1 bound to MUC5AC. These data support the
contention that TFF1 is pivotal in the packaging and function of human gastric mucusa.Received 24 March 2004; received after revision 14 May 2004; accepted 7 June 2004 相似文献
96.
Waschek JA 《Cellular and molecular life sciences : CMLS》2004,61(18):2332-2342
The concept that atrial natriuretic peptide (ANP) and the closely related peptides BNP and CNP might be involved in the ontogeny of several organ systems emerged in the late 1980s. While many of the reported in vitro actions have not been examined in the context of organ development in vivo, recent studies demonstrate that mice which lack or overexpress natriuretic peptides or receptors exhibit pronounced skeletal growth defects. This article discusses how natriuretic peptides and other factors appear to regulate bone growth as an example of how natriuretic peptides might participate in the ontogeny of other organ systems. Evidence indicating that natriuretic peptides regulate neural development is then reviewed. Natriuretic peptides and receptors exhibit complex expression patterns in the developing nervous system, where they have been shown to act on neural cells as early as at the embryonic neural tube stage. Interestingly, both bone and brain growth appear to utilize primarily CNP and the CNP-specific type B receptor, and perhaps the type C receptor. In vitro data indicate that CNP may act on developing neurons, astrocytes and Schwann cells like a classical growth factor, regulating proliferation, patterning, phenotypic specification, survival and axonal pathfinding. Natriuretic peptides might also have roles in the vascularization of the embryonic brain, establishment of the blood-brain and blood-nerve barriers, and perhaps in nerve regeneration.Received 13 April 2004; received after revision 20 May 2004; accepted 27 May 2004 相似文献
97.
王虎承 《重庆工商大学学报(自然科学版)》2005,22(2):143-147,193
运用比较分子力场(CoMFA)和比较相似性指数分析(CoMSIA)方法研究了50个HLA-A* 0201限制性CTL表位九肽结构与亲和性间的关系,另外15个表位九肽作为预测集用于检验模型的预测能力。结果表明,采用CoMSIA得到的构效关系模型(q2 =0.608,r2 =0.987,F=440.4,SD=0. 111)要明显优于采用CoMFA得到的构效关系模型。在CoMSIA计算中,当引入疏水场时,三维构效关系模型得到明显改善,通过该三维构效关系模型,可较精确地估算预测集中15个CTL表位肽与HLA-A* 0201间的亲和力(r2pred=0. 703,SD=0. 368)。通过分析分子场等势面图在空间的分布,可以观察到表位肽分子周围的立体及疏水特征对表位肽与HLA-A* 0201间结合亲和力的影响,从而为进一步对CTL表位肽进行结构改造并基于此进行治疗性疫苗分子设计提供理论基础。 相似文献
98.
99.
运用荧光和紫外吸收光谱研究了Ru(bipy)2(dppz)^2 和苯胺红T两种荧光试剂与PNA-DNA、dsDNA之间的相互作用.实验结果表明:相同条件下同一荧光试剂与PNA—DNA、dsDNA两者之间发生不同的作用,从而说明了PNA-DNA、dsDNA的结构具有一定的差异,并对引起差异的原因进行了初步的探讨。 相似文献
100.
DUJintang LIYanmei ZHUZhentai CHENYi ZHAOYufen 《科学通报(英文版)》2003,48(21):2317-2319
The cationized 9-fluorenylmethoxycarbonyl (Fmoc) protected amino acids were analyzed by the electrospray ionization tandem mass spectrometry (ESI-MS/MS). A rearrangement reaction leading to the C-terminal hydroxyl group transfer was observed. The sodium adducts of Fmoc-OH was formed. A possible rearrangement mechanism was proposed. The rearrangement reaction depended on the Fmoc group, metal ions and metal ion radius. It was shown that the Fmoc group has a strong affinity to the hydroxyl group in the gas phase. 相似文献