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51.
Multimeric BLM is dissociated upon ATP hydrolysis and functions as monomers in resolving DNA structures 总被引:1,自引:0,他引:1
Ya-Nan Xu Nicolas Bazeille Xiu-Yan Ding Xi-Ming Lu Peng-Ye Wang Elisabeth Bugnard Virginie Grondin Shuo-Xing Dou Xu Guang Xi 《Nucleic acids research》2012,40(19):9802-9814
Bloom (BLM) syndrome is an autosomal recessive disorder characterized by an increased risk for many types of cancers. Previous studies have shown that BLM protein forms a hexameric ring structure, but its oligomeric form in DNA unwinding is still not well clarified. In this work, we have used dynamic light scattering and various stopped-flow assays to study the active form and kinetic mechanism of BLM in DNA unwinding. It was found that BLM multimers were dissociated upon ATP hydrolysis. Steady-state and single-turnover kinetic studies revealed that BLM helicase always unwound duplex DNA in the monomeric form under conditions of varying enzyme and ATP concentrations as well as 3′-ssDNA tail lengths, with no sign of oligomerization being discerned. Measurements of ATPase activity further indicated that BLM helicase might still function as monomers in resolving highly structured DNAs such as Holliday junctions and D-loops. These results shed new light on the underlying mechanism of BLM-mediated DNA unwinding and on the molecular and functional basis for the phenotype of heterozygous carriers of BLM syndrome. 相似文献
52.
野生青果的防腐作用研究 总被引:11,自引:0,他引:11
本文对野生青果的药用成分进行了鉴定及制备,证明了该成分具有较强的抑菌作用,并同常用的合成防腐剂苯甲酸钠、山梨酸钾的防腐性能进行了比较。 相似文献
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Staphylococcus capitis is a subtype of coagulase-negative staphylococci (CoNS) which could emerge as a significant pathogen causing infective endocarditis, prosthetic valve endocarditis, and late-onset sepsis. We isolated S. capitis strain QN1 from the skin swab sample of a female. Here we prepared a genome sequence for this strain consisting of 30 contigs totaling 2,430,101 bases and a GC content of 32.76%. 相似文献
55.
目的寻求治疗结核包囊性胸腔积液的新方法。方法胸膜活检确诊为结核性胸腔积液并经B超或胸部X线证实有粘连包囊的病人15例,经胸腔内注入尿激酶每次10万单位,用60ml生理盐水稀释,每8~12h重复,连续5次,每次记录抽取胸水总量,并复查B超观察粘连包囊情况。对照组为单纯用抗结核治疗及间断抽胸水15例。结果实验组13例有效,总有效率86.7%。对照组2例有效,有效率13.3%,疗效明显优于对照组(P<0.05)。结论尿激酶胸腔内注入是治疗结核性粘连包囊性胸腔积液的一种安全可靠的新方法。 相似文献
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人Ⅳ型胶原的提纯及其抗血清制备 总被引:1,自引:0,他引:1
采用胃蛋白酶限制性消化,NaCl分级盐析,还原和烷基化反应,纤维素离子交换层析从人胎盘组织分离纯化Ⅳ型胶原.经SDS-PAGE电泳鉴定符合Ⅳ型胶原α肽链电泳带.用纯化的Ⅳ型胶原免疫兔制备出高效价的特异抗血清. 相似文献
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The complete mitogenome of Haliotis iris, an economically important shellfish endemic to New Zealand, was sequenced for the first time. The mitogenome was 17,131?base pairs (bp) in length and contained 13 protein-coding genes (PCGs), 2 ribosomal RNA (rRNA) genes, 22 transfer RNA (tRNA) genes and a control region. All 13 genes were initiated by the start codon ATG, except for nad5 (ATA). Two typical stop codons, TAA and TAG, were present. All of the tRNAs could be folded into typical cloverleaf secondary structures except tRNASer1 and tRNALys, which lacked a DHU stem and complete amino acid acceptor stem, respectively. The control region was 1132?bp in length and contained six AT tandem repeats. According to the gene order of the mitogenome, the 30 analysed Vetigastropoda species could be classified into three types—type I: over half of the studied species were very similar to the gastropod ancestral gene order, and the rearrangements occurred in five tRNAs; type II: eight species were found to be missing several tRNA genes; type III: Fissurellidae, Lepetodrilidae showed a large inverted fragment. 相似文献