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Topography of the TH5 Segment in the Diphtheria Toxin T-Domain Channel

文献类型：期刊论文

作者Kienker, Paul K.1; Wu, Zhengyan1,3; Finkelstein, Alan1,2
刊名JOURNAL OF MEMBRANE BIOLOGY
出版日期2016-04-01
卷号249期号:1-2页码:181-196
关键词Bacterial Toxins Ion-conducting Channels Kinetics Lipid Bilayers Sulfhydryl Reagents
DOI10.1007/s00232-015-9859-9
文献子类Article
英文摘要The translocation domain (T-domain) of diphtheria toxin contains 10 alpha helices in the aqueous crystal structure. Upon exposure to a planar lipid bilayer under acidic conditions, it inserts to form a channel and transport the attached amino-terminal catalytic domain across the membrane. The TH5, TH8, and TH9 helices form transmembrane segments in the open-channel state, with TH1-TH4 translocated across the membrane. The TH6-TH7 segment also inserts to form a constriction that occupies only a small portion of the total channel length. Here, we have examined the TH5 segment in more detail, using the substituted-cysteine accessibility method. We constructed a series of 23 mutant T-domains with single cysteine residues at positions in and near TH5, monitored their channel formation in planar lipid bilayers, and probed for an effect of thiol-specific reagents added to the solutions on either side of the membrane. For 15 of the mutants, the reagent caused a decrease in single-channel conductance, indicating that the introduced cysteine residue was exposed within the channel lumen. We also found that reaction caused large changes in ionic selectivity for some mutant channels. We determined whether reaction occurred in the open state or in the brief flicker-closed state of the channel. Finally, we compared the reaction rates from either side of the membrane. Our experiments are consistent with the hypotheses that the TH5 helix has a transmembrane orientation and remains helical in the open-channel state; they also indicate that the middle of the helix is aligned with the constriction in the channel.
WOS关键词PLANAR LIPID-BILAYERS ; TRANSMEMBRANE HAIRPIN ; MEMBRANE INSERTION ; CATALYTIC DOMAIN ; PORE ; PROTEIN ; TRANSLOCATION ; MECHANISM ; ORGANIZATION ; HELICES-8
WOS研究方向Biochemistry & Molecular Biology ; Cell Biology ; Physiology
语种英语
WOS记录号WOS:000375553500021
资助机构National Institutes of Health(GM29210) ; National Institutes of Health(GM29210) ; National Institutes of Health(GM29210) ; National Institutes of Health(GM29210) ; National Institutes of Health(GM29210) ; National Institutes of Health(GM29210) ; National Institutes of Health(GM29210) ; National Institutes of Health(GM29210) ; National Institutes of Health(GM29210) ; National Institutes of Health(GM29210) ; National Institutes of Health(GM29210) ; National Institutes of Health(GM29210) ; National Institutes of Health(GM29210) ; National Institutes of Health(GM29210) ; National Institutes of Health(GM29210) ; National Institutes of Health(GM29210)
源URL[http://ir.hfcas.ac.cn:8080/handle/334002/22394]  
专题合肥物质科学研究院_技术生物与农业工程研究所
作者单位1.Albert Einstein Coll Med, Dept Physiol & Biophys, 1300 Morris Pk Ave, Bronx, NY 10461 USA
2.Albert Einstein Coll Med, Dept Neurosci, 1300 Morris Pk Ave, Bronx, NY 10461 USA
3.Chinese Acad Sci, Hefei Inst Phys Sci, Key Lab Ion Beam Bioengn, Hefei 230031, Anhui, Peoples R China
推荐引用方式
GB/T 7714		 Kienker, Paul K.,Wu, Zhengyan,Finkelstein, Alan. Topography of the TH5 Segment in the Diphtheria Toxin T-Domain Channel[J]. JOURNAL OF MEMBRANE BIOLOGY,2016,249(1-2):181-196.
APA Kienker, Paul K.,Wu, Zhengyan,&Finkelstein, Alan.(2016).Topography of the TH5 Segment in the Diphtheria Toxin T-Domain Channel.JOURNAL OF MEMBRANE BIOLOGY,249(1-2),181-196.
MLA Kienker, Paul K.,et al."Topography of the TH5 Segment in the Diphtheria Toxin T-Domain Channel".JOURNAL OF MEMBRANE BIOLOGY 249.1-2(2016):181-196.

入库方式： OAI收割

来源：合肥物质科学研究院

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