共查询到20条相似文献，搜索用时 31 毫秒
1.
Immunoglobulin structure: amino terminal sequences of mouse myeloma proteins that bind phosphorylcholine 总被引：26，自引：0，他引：26
P Barstad S Rudikoff M Potter M Cohn W Konigsberg L Hood 《Science (New York, N.Y.)》1974,183(128):962-966
The amino terminal sequences of five light and heavy immunoglobulin chains from myeloma proteins of the BALB/c mouse with binding activity to phosphorylcholine are presented. Except for a single substitution in position 4, all five heavy chains have identical amino terminal sequences through the first hypervariable region. Proteins which share unique (idiotypic) antigenic determinants are identical through the first hypervariable region of their light and heavy chains. Proteins with differing idiotypic determinants have light chains of differing amino acid sequence. These observations suggest that the heavy chain plays a more important role than the light chain in determining the phosphorylcholine binding site. 相似文献
2.
More protein is required to detect the Inv(1) antigen carried in the light chain of immunoglobulin G molecules when the light chain is combined with a gamma2 heavy chain than when it is combined with a gamma1 or gamma3 heavy chain. One of the four gamma2 heavy chains used in the experiment, however, was as efficient as the gamma1 and gamma3 chains, indicating that there may be two subtypes of gamma2. Inv(1) was more easily detected in one of the two light chains used in the experiment. This difference may be associated with the subtypes of the kappa chain derived from studies of the variable portion of the chain. 相似文献
3.
The amino acid sequence of the micro, chain of a human IgM immunoglobulin, including the location of all disulfide bridges and oligosaccharides, has been determined. The homology of the constant regions of immunoglobulin micro, gamma, alpha, and epsilon heavy chains reveals evolutionary relationships and suggests that two genes code for each heavy chain. 相似文献
4.
应用RT-PCR技术克隆获得了一株C型口蹄疫病毒鼠源毒株的非结构蛋白3A基因(C-3A),并对其进行序列测定及分析.结果表明,C-3A编码全基因序列中核苷酸共435 bp,编码氨基酸145个;与12株参考毒株比较发现,C型毒株核苷酸序列在第274~297位发生了缺失,氨基酸在92~99位发生缺失.核苷酸的同源性比较显示,C-3A基因与YNBS/58-3A基因的同源性最高,为82.8%;C-3A基因与TW/97-3A基因的同源性最低,为72.5%.氨基酸的同源性比较表明,C-3A基因与OIC/58-3A基因的同源性最高,为86.9%;与TW/97-3A基因的同源性最低,为72.7%. 相似文献
5.
A G protein gamma subunit shares homology with ras proteins 总被引：18，自引：0，他引：18
Guanine nucleotide binding proteins (G proteins) that transduce signals from cell surface receptors to effector molecules are made up of three subunits, alpha, beta, and gamma. A complementary DNA clone that encodes a 71-amino acid protein was isolated from bovine brain; this protein contains peptide sequences that were derived from the purified gamma subunit of Gi and Go. The primary sequence of this G protein gamma subunit (G gamma) has 55 percent homology to the gamma subunit of transducin (T gamma) and also has homology to functional domains of mammalian ras proteins. The probe for isolating the clone was generated with the use of the polymerase chain reaction (PCR). The extent of divergence between T gamma and G gamma, the isolation of homologous PCR-generated fragments, and the differences between the predicted amino acid sequence of G gamma and that derived from the gamma subunit of Gi and Go indicate that gamma subunits are encoded by a family of genes. 相似文献
6.
福建黄兔是中国优良的小型兼用品种，从线粒体水平分析福建黄兔在兔形目动物中的系统发育地位，对探究其起源、进化和种群分类具有重要意义。利用PCR高保真扩增技术和生物信息学软件对福建黄兔线粒体基因组进行获取、拼接与注释。结果发现福建黄兔线粒体基因组全长17 000 bp(Genbank No.MN518689)，主要包括tRNA基因（22个）、rRNA基因（2个）、蛋白编码基因（13个）和控制区（1个）4 部分，基因排列紧密。除控制区，共存在37个编码基因，有9个基因由轻链（L链）编码，其余28个编码基因均由重链（H链）编码。22个tRNA基因中，除 tRNA-Ser(AGY)基因由于缺失DHU臂不能形成三叶草结构外，其余21种tRNA基因均可折叠形成经典的三叶草结构。控制区含有3种结构域：延长终止序列区（ETAS1和ETAS2）、中央保守区、保守序列区（CSB1、CSB2和CSB3），其中，CSB1和CSB2间存在200 bp的短重复序列，CSB3和tRNA-Phe间存在306 bp的长重复序列。基于线粒体基因组控制区序列构建10 种兔形目动物的系统进化树，结果表明福建黄兔起源于穴兔，支持将福建黄兔划归为穴兔属。 相似文献
7.
猪IgG H链基因CH2-CH3的克隆和分析 总被引：1，自引：0，他引：1
根据已发表的猪IgG H链序列,设计了1对通用引物,从猪外周血淋巴细胞提取总RNA,经RT-PCR扩增IgG H链基因CH2-CH3序列,并克隆入pMD18-T Simple载体,转化大肠杆菌DH5α感受态细胞,经SalI和XbaI双酶切鉴定,筛选出阳性克隆。核酸序列测定分析表明,IgG H链基因CH2-CH3序列全长为669 bp,编码CH2-CH3的221个氨基酸和J区的1个脯氨酸。利用DNASTAR软件将其与猪IgG H链各CH2-CH3序列进行比较,发现其与U03778-1、U03779-2a、U03780-2b、U03781-3、U03782-4的核苷酸序列同源率分别为92.1%、98.4%、98.5%、93.0%和97.2%,推导的氨基酸序列同源率分别为86.5%、96.4%、96.5%、87.0%和94.2%。经进化树分析提示,该序列可能为一个新的亚型。 相似文献
8.
XU Ri-fu LI Kui CHEN Guo-hong QIANG Ba-yang-zong MO De-lin LI Chang-chun FAN Bin LIU Bang 《中国农业科学(英文版)》2005,4(4)
A fragment spanning over exon 2 and intron 2 of major histocompatibility complex B-LB Ⅱ genes was amplified using PCR,cloned and sequenced in 13 individuals from eight Chinese indigenous chicken breeds and one introduced breed. Another 41 sequences of MHC class Ⅱβ from ten vertebrate species were cited from the NCBI GenBank. Thirteen new B-LB Ⅱ alleles were found in the chicken breeds sampled. Alignment of the exon 2 sequences revealed 91.1-97.8% similarity to each other within the chickens sampled, and the chickens shared 84.1-87.0% homology to Phasianus colchicus, 78.5-81.5% similarity to Coturnixjaponica. The sequences in poultry showed 62.6-68.1% identity to HLA-DRBl, 50-61.5% similarity to DQB (HLA-, SLA- and H2-BB), 53.7-60% to HLA-DPB and 53.3-57.8% similarity to HLA-DOB. The frequency of nonsynonymous substitutions of nucleotide was higher than that of synonymous substitutions, and the frequencies of nonsynonymous and synonymous substitutions in poultry B-LB Ⅱ genes were lower than those observed in mammalian DRB1 and DQB1 genes. The deduced amino acid sequences of MHC class Ⅱβ1 domain exhibited extreme difference in conversed region and variable region patterns among the various species, but the two conserved cysteines forming disulfide-bond were shown consistent in poultry with that in mammalian species; and the carbohydrate attachment site was found more conserved in chicken, Homo sapiens, Bos taurus, Ovis aries and Capra hircus than in Sus scrofa and rodent animals. Compared with exon 2 of DQB1 genes of Homo sapiens, ruminant species and Sus scrofa, the differentia that the deletion of six nucleotides at position195 to 200 of exon 2 of DQB1 genes, and insertion of three nucleotides at position 247 to 249 of the exon 2 existed in rodent species were found, which led to the absence of three AA residues at position 65, 66,and 67 within β1 domain of DQB1 chain, and the insertion of one AA residue at position 85. The difference of the deletion of six nucleotides at position 72 to 77 of exon 2 of DPB1 genes was observed with Homo sapiens DQB1, which caused absence of three AA residues at position 24, 25, and 26 of β1 domain of DPBl chain. The phylogenetic tree revealed that the B-LB Ⅱ sequences from poultry are not orthologous to the class Ⅱ MHC β-chain genes of mammalian species. The tree indicated that genetic evolutionary relationship of chickens with Phasianus colchicus was much closer than with Coturnixjaponica, and the DQB and DPB clusters are more tightly related to each other than to the remaining clusters. 相似文献
9.
The amino acid sequence of urinary beta(2)-microglobulin has been partially determined and found to be related to the constant region of IgG immunoglobulin heavy chain. beta(2)-Microglobulin is present in normal individuals. Its gene may have evolved from an immunoglobulin gene by the use of an unusually located start signal for initiating synthesis of the polypeptide. 相似文献
10.
罗非鱼免疫球蛋白（IgM）重链基因全长cDNA序列分析 总被引：1，自引：0，他引：1
从已经构建的罗非鱼白细胞cDNA文库中测定获得罗非鱼免疫球蛋白（IgM）重链的eDNA序列,全长1885bp,有一个完整ORF阅读框长1770bp,5’UTR为29bp,3’-UTR为86bp,编码588个氨基酸。罗非鱼与大黄鱼、斜带石斑鱼、南极鳕鱼、乌鳢、鳜鱼、伯氏豚[鱼叚]虎鱼、牙鲆、花狼鱼、硬头鳟的IgM重链氨基酸序列有较高的同源性,最高达到69％,表明已经获得罗非鱼IgM重链基因;对所得氨基酸进行二级结构预测发现,罗非鱼IgM重链基因全长cDNA序列所编码的氨基酸分子量为41453．94Da。该试验结果为罗非鱼IgM重链基因功能的实验性鉴定工作奠定了基础。 相似文献
11.
DNA sequences mediating class switching in alpha-immunoglobulins 总被引：49，自引：0，他引：49
Immunoglobulin class switching involves specific DNA rearrangements of the gene segments coding for heavy chain constant regions (CH) during B lymphocyte differentiation. In two different cases of C mu to C alpha switching examined here (T15 and M603) and one taken from the literature (MC101), three different sites on the 5' side of C mu and three different sites on the 5' side of C alpha are joined together in the process of CH switching. The sequences surrounding the three germ-line C alpha sites of recombination are highly conserved blocks of 30 nucleotides that may serve as recognition sequences for CH switching to the C alpha gene. This putative recognition sequence is repeated 17 times in approximately 1400 nucleotides of the germ-line Calpha 5' flanking sequence. The lack of homology between this C alpha sequence and sequences reported for the C gamma 1 and C gamma 2b switch sites suggests that heavy chain switching is mediated by class-specific recognition sequences and, presumably, class-specific regulatory mechanisms. In addition, it appears that in one example (MC101) CH switching progressed from C mu to C alpha to C gamma 1. This switching pathway may present difficulties for the simple deletional model of CH switching. 相似文献
12.
根据抗玉米赤霉烯酮毒素单链抗体的氨基酸序列及大肠杆菌偏爱密码子,用重叠延伸PCR法合成了单链抗体的重链和轻链,经（Gly4Ser）2Linker连接,获得完整的单链抗体基因ZEN2 scFv。将ZEN2 scFv与碱性磷酸酶（AP）编码序列连接形成融合蛋白基因ZEN2 scFv-AP,构建到pET载体,转化大肠杆菌菌株BL21（DE3）,经IPTG诱导表达及亲和层析纯化,在SDS-PAGE和Western blot分析中均检测到1条分子质量为75 ku的可溶性蛋白条带,ELISA分析证实,细菌表达的ZEN2 scFv-AP融合蛋白具有碱性磷酸酶活性。这一研究结果为建立快速、灵敏、经济的玉米赤霉烯酮毒素的ELISA检测奠定了基础。 相似文献
13.
C Y Kang T K Brunck T Kieber-Emmons J E Blalock H Kohler 《Science (New York, N.Y.)》1988,240(4855):1034-1036
The self-binding properties of a dominant idiotypic antibody (T15) and a minor idiotypic antibody (M603), both specific for phosphorylcholine, were examined as models of self-binding antibodies (autobodies). Observed differences in the self-binding affinity of T15 and M603 relate to variable sequence differences in their respective heavy and light chains. A molecular recognition theory based on the translation of coding and noncoding DNA strands was used to identify complementary amino acid sequences responsible for self-binding. The second hypervariable region of the heavy chain domain, extending into the third framework region, was predicted as the primary self-binding locus. Among peptides synthesized with different variable heavy and light chain regions, a 24-residue peptide spanning the second hypervariable and third framework regions of the heavy chain of T15 was nearly as effective as phosphorycholine in inhibiting the self-binding complexes. 相似文献
14.
黄羽扇豆翻译延伸因子2的序列分析 总被引：3，自引：0，他引：3
利用Sanger双脱氧链终止法对黄羽扇豆（Lupinusluteus）翻译延伸因子2（EF2）的全长cDNA克隆进行了序列分析。该cDNA长度为2794bp,其中包括5’末端的80bp非翻译区,3’末端185bp非翻译区和2529bp长编码序列,3’末端为一18bp poly（A）尾。与其它GTP结合蛋白比较其编译的843aa（氨基酸）序列,发现它们具有显著的同源性;黄羽扇豆EF2与甜菜EF2的氨基酸序列90％相同。其差异主要存在于序列的中部;而与肽基tRNA和核糖体作用部位、与GTP结合部位和GTP酶活性有关的部位具有很高的保守性。黄羽扇豆EF2第700个氨基酸残基组氨酸是白喉毒素的ADP-核糖基化部位。 相似文献
15.
16.
Clathrin light chains LCA and LCB are similar, polymorphic, and share repeated heptad motifs 总被引：19，自引：0，他引：19
T Kirchhausen P Scarmato S C Harrison J J Monroe E P Chow R J Mattaliano K L Ramachandran J E Smart A H Ahn J Brosius 《Science (New York, N.Y.)》1987,236(4799):320-324
The clathrin light chains fall into two major classes, LCA and LCB. In an intact clathrin triskelion, one light chain, of either class, is bound to the proximal segment of a heavy chain leg. Analysis of rat brain and liver complementary DNA clones for LCA and LCB shows that the two light chain classes are closely related. There appear to be several members of each class having deletions of varying length aligned at the same position. A set of ten heptad elements, characteristic of alpha-helical coiled coils, is a striking feature of the central part of each derived amino acid sequence. These observations suggest a model in which the alpha-helical segment mediates binding to clathrin heavy chains and the amino- and carboxyl-terminal segments mediate interactions with other proteins. They also suggest an explanation for the observed tissue-dependent size variation for members of each class. 相似文献
17.
The variable regions of the light and heavy chains on the same macroglobulin (immunoglobulin M) molecule are no more related in amino acid sequence than are the variable regions of the light and heavy chains of different immunoglobulin molecules. Subgroups of micro chains are similar in their variable sequence to subgroups of gamma chains. 相似文献
18.
Somatic mutation in genes for the variable portion of the immunoglobulin heavy chain 总被引：11，自引：0，他引：11
J Sims T H Rabbitts P Estess C Slaughter P W Tucker J D Capra 《Science (New York, N.Y.)》1982,216(4543):309-311
The size of the gene pool potentially encoding antibodies to p-azophenyl arsonate has been examined. A heavy chain-specific full-length complementary DNA clone has been constructed with the use of messenger RNA from a hybridoma that produces antibodies to the arsonate hapten and bears nearly a full complement of the determinants comprising the cross-reactive idiotype (CRI). The sequences of both the complementary DNA clone and the corresponding immunoglobulin heavy chain have been independently determined. A probe for the variable region gene was prepared from the original heavy chain complementary DNA clone and used to analyze, by Southern filter hybridization, genomic DNA from both A/J (CRI positive) and BALB/c (CRI negative) mice. Approximately 20 to 25 restriction fragments containing "germline" variable region gene segments were detected in both strains, and many are shared by both, Since 35 CRI-positive heavy chains have been partially sequenced thus far and 31 are different, the results of the hybridization analysis suggest that somatic mutation events involving the variable region gene segments of the heavy chain play a role in the origin of the amino acid sequence diversity seen in this system. 相似文献
19.
【目的】从栽培大麦（Hordeum vulgare）中分离并克隆对植物细胞周期起负调控作用的RBR（retinoblastoma-related）,鉴定大麦RBR（HvRBR）分子特征,明确其与同源基因间的亲缘关系和分类地位,为探索动、植物生长发育过程中细胞增殖和分化相关调控途径的研究提供理论依据。【方法】通过对植物RBR生物信息学分析,根据RBR保守区域序列设计通用引物,采用PCR方法从栽培大麦DNA和苗期总cDNA中分别分段克隆,获得特征序列后在DNAMAN软件下进行序列分析、多重序列比对并构建系统树。【结果】从栽培大麦籽粒皱缩突变材料GSHO1854中获得全长为5 547 bp的大麦HvRBR序列（GU121481）,其cDNA编码区（GU121480）全长3 179 bp,包含一个编码975个氨基酸的开放阅读框。由其推导的氨基酸序列与已报道的RBR蛋白序列有较高的一致性。在A、B保守区之间有一个间隔区,虽然同源性较低,但是所有氨基酸序列的相似位点都包含一个半胱氨酸残基,这说明该半胱氨酸残基形成的分子内或分子间二硫键可能对整个RBR蛋白的结构和功能产生重要的影响。系统进化分析表明HvRBR与水稻同源性最高（84.3%）,与苜蓿、拟南芥等双子叶植物的同源性较低（50%）。【结论】首次从大麦中得到与植物细胞周期起调控、细胞增殖和分化相关的RBR蛋白编码基因HvRBR。对栽培大麦籽粒皱缩突变材料GSHO1854的HvRBR进行了分子克隆和鉴定,并通过系统进化分析将HvRBR归为植物RBR家族C亚族。 相似文献
20.
Identification of the cystic fibrosis gene: genetic analysis 总被引：316，自引：0，他引：316
B Kerem J M Rommens J A Buchanan D Markiewicz T K Cox A Chakravarti M Buchwald L C Tsui 《Science (New York, N.Y.)》1989,245(4922):1073-1080
Approximately 70 percent of the mutations in cystic fibrosis patients correspond to a specific deletion of three base pairs, which results in the loss of a phenylalanine residue at amino acid position 508 of the putative product of the cystic fibrosis gene. Extended haplotype data based on DNA markers closely linked to the putative disease gene locus suggest that the remainder of the cystic fibrosis mutant gene pool consists of multiple, different mutations. A small set of these latter mutant alleles (about 8 percent) may confer residual pancreatic exocrine function in a subgroup of patients who are pancreatic sufficient. The ability to detect mutations in the cystic fibrosis gene at the DNA level has important implications for genetic diagnosis. 相似文献