Abstract：
:The DnaB protein is the primary replicative helicase in Escherichia coli, and the active form of the protein is a hexamer. It has been reported that the protein forms a ring with strong 3-fold symmetry, which was suggested to be a trimer of dimers. We show that under different conditions, using either ATP, ATP gamma S, AMP-PNP or ADP as nucleotide cofactors, we always find two different forms of the DnaB ring; one with a 3-fold symmetry and one with 6-fold symmetry. We have used scanning transmission electron microscopy for mass analysis, and have found that both forms are hexamers, excluding the possibility that the 3-fold form is in fact a trimer of the 52 kDa monomer. We have also found rings that are in an intermediate state between these two. The existence of hexamers in discrete states shows that the transitions between these states must be cooperative. These observations suggest that there may be an equilibrium between two different conformations of the hexameric ring. The role of these two states in the mechanism of helicase action remains to be determined.
journal_name
J Mol Bioljournal_title
Journal of molecular biologyauthors
Yu X,Jezewska MJ,Bujalowski W,Egelman EHdoi
10.1006/jmbi.1996.0297subject
Has Abstractpub_date
1996-05-31 00:00:00pages
7-14issue
1eissn
0022-2836issn
1089-8638pii
S0022283696902971journal_volume
259pub_type
杂志文章abstract：:Ribgrass mosaic virus (RMV) is a member of the tobamovirus group of plant viruses. The structure has been determined at 2.9 A resolution by fiber diffraction methods, and refined by molecular dynamics methods to an R-factor of 0.095. The carboxyl-carboxylate interactions that drive disassembly in tobamoviruses are pre...
journal_title：Journal of molecular biology
pub_type： 杂志文章
doi：10.1006/jmbi.1997.1048
更新日期：1997-06-27 00:00:00
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journal_title：Journal of molecular biology
pub_type： 杂志文章
doi：10.1006/jmbi.2001.4802
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journal_title：Journal of molecular biology
pub_type： 评论,杂志文章
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更新日期：2014-04-03 00:00:00
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journal_title：Journal of molecular biology
pub_type： 杂志文章
doi：10.1006/jmbi.1993.1416
更新日期：1993-07-20 00:00:00
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journal_title：Journal of molecular biology
pub_type： 杂志文章
doi：10.1016/0022-2836(85)90138-x
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journal_title：Journal of molecular biology
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doi：10.1016/j.jmb.2011.04.013
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journal_title：Journal of molecular biology
pub_type： 杂志文章
doi：10.1006/jmbi.1995.0608
更新日期：1995-11-24 00:00:00
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journal_title：Journal of molecular biology
pub_type： 杂志文章
doi：10.1016/j.jmb.2007.09.077
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pub_type： 杂志文章
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更新日期：1990-12-05 00:00:00
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journal_title：Journal of molecular biology
pub_type： 杂志文章
doi：10.1006/jmbi.2001.5312
更新日期：2002-02-15 00:00:00
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journal_title：Journal of molecular biology
pub_type： 杂志文章
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更新日期：2010-03-26 00:00:00
abstract：:The Tetrahymena intron, after splicing from its flanking exons, can mediate its own circularization. This is followed by site-specific hydrolysis of the phosphodiester bond formed during the circularization reaction. The structural components involved in recognition of this bond for hydrolysis have not been establishe...
journal_title：Journal of molecular biology
pub_type： 杂志文章
doi：10.1016/0022-2836(92)90736-4
更新日期：1992-01-05 00:00:00
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journal_title：Journal of molecular biology
pub_type： 杂志文章
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更新日期：2000-04-28 00:00:00
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journal_title：Journal of molecular biology
pub_type： 杂志文章
doi：10.1006/jmbi.1996.0277
更新日期：1996-05-17 00:00:00
abstract：:Under usual laboratory conditions, lysis by bacteriophage lambda requires only the holin and endolysin genes, but not the Rz and Rz1 genes, of the lysis cassette. Defects in Rz or Rz1 block lysis only in the presence of high concentrations of divalent cations. The lambda Rz and Rz1 lysis genes are remarkable in that R...
journal_title：Journal of molecular biology
pub_type： 杂志文章
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更新日期：2007-11-09 00:00:00
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journal_title：Journal of molecular biology
pub_type： 杂志文章
doi：10.1016/j.jmb.2003.11.038
更新日期：2004-01-30 00:00:00
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journal_title：Journal of molecular biology
pub_type： 杂志文章
doi：10.1016/0022-2836(84)90258-4
更新日期：1984-12-25 00:00:00
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journal_title：Journal of molecular biology
pub_type： 杂志文章
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更新日期：2001-09-14 00:00:00
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journal_title：Journal of molecular biology
pub_type： 杂志文章
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更新日期：2001-07-13 00:00:00
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journal_title：Journal of molecular biology
pub_type： 杂志文章
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journal_title：Journal of molecular biology
pub_type： 杂志文章
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journal_title：Journal of molecular biology
pub_type： 杂志文章
doi：10.1016/0022-2836(91)90876-8
更新日期：1991-03-05 00:00:00
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journal_title：Journal of molecular biology
pub_type： 杂志文章
doi：10.1006/jmbi.1994.1081
更新日期：1994-01-28 00:00:00
abstract：:The Fv fragment from an anti-dansyl antibody was optimally crystallized into two crystal forms having slightly different lattice dimensions at pH 5.25 and 6.75. The two crystal structures were determined and refined at high resolution at 112 K (at 1.45 A for the crystal at pH 5.25 and at 1.55 A for that at pH 6.75). I...
journal_title：Journal of molecular biology
pub_type： 杂志文章
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更新日期：1999-08-06 00:00:00
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journal_title：Journal of molecular biology
pub_type： 杂志文章
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更新日期：2015-02-27 00:00:00
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journal_title：Journal of molecular biology
pub_type： 杂志文章
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更新日期：2006-10-20 00:00:00
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journal_title：Journal of molecular biology
pub_type： 杂志文章
doi：10.1006/jmbi.2000.3737
更新日期：2000-06-02 00:00:00
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journal_title：Journal of molecular biology
pub_type： 杂志文章
doi：10.1016/j.jmb.2008.06.081
更新日期：2008-10-31 00:00:00
abstract：:The Psi-RNA packaging signal of the human immunodeficiency virus type-1 (HIV-1) genome contains a 35 nucleotide stem-loop, termed SL1, which is important for efficient genome packaging during virus assembly and for reverse transcription during infectivity. The predicted secondary structure of SL1 consists of an upper ...
journal_title：Journal of molecular biology
pub_type： 杂志文章
doi：10.1016/s0022-2836(02)01305-0
更新日期：2003-02-14 00:00:00
abstract：:Increasing evidence indicates that transcriptionally silent chromatin structure is dynamic and may change its conformation in response to external or internal stimuli. We show that growth temperature affects all three forms of transcriptional silencing in Saccharomyces cerevisiae. In general, increasing the temperatur...
journal_title：Journal of molecular biology
pub_type： 杂志文章
doi：10.1016/j.jmb.2004.10.002
更新日期：2004-12-03 00:00:00
