2IPC

Crystal structure of the translocation ATPase SecA from Thermus thermophilus reveals a parallel, head-to-head dimer


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.80 Å
  • R-Value Free: 0.255 
  • R-Value Work: 0.221 
  • R-Value Observed: 0.221 

wwPDB Validation 3D Report Full Report


This is version 1.2 of the entry. See complete history


Literature

Crystal Structure of the Translocation ATPase SecA from Thermus thermophilus Reveals a Parallel, Head-to-Head Dimer.

Vassylyev, D.G.Mori, H.Vassylyeva, M.N.Tsukazaki, T.Kimura, Y.Tahirov, T.H.Ito, K.

(2006) J Mol Biol 364: 248-258

  • DOI: 10.1016/j.jmb.2006.09.061
  • Structures With Same Primary Citation

  • PubMed Abstract: 
  • The mechanism of pre-protein export through the bacterial cytoplasmic membrane, in which the SecA ATPase plays a crucial role as an "energy supplier", is poorly understood. In particular, biochemical and structural studies provide contradictory data ...

    The mechanism of pre-protein export through the bacterial cytoplasmic membrane, in which the SecA ATPase plays a crucial role as an "energy supplier", is poorly understood. In particular, biochemical and structural studies provide contradictory data as to the oligomeric state of SecA when it is integrated into the active trans-membrane translocase. Here, we report the 2.8 A resolution crystal structure of the Thermus thermophilus SecA protein (TtSecA). Whereas the structure of the TtSecA monomer closely resembles that from other bacteria, the oligomeric state of TtSecA is strikingly distinct. In contrast to the antiparallel (head-to-tail) dimerization reported previously for the other bacterial systems, TtSecA forms parallel (head-to-head) dimers that are reminiscent of open scissors. The dimer interface is abundant in bulky Arg and Lys side-chains from both subunits, which stack on one another to form an unusual "basic zipper" that is highly conserved, as revealed by homology modeling and sequence analysis. The basic zipper is sealed on both ends by two pairs of the salt bridges formed between the basic side-chains from the zipper and two invariant acidic residues. The organization of the dimers, in which the two pre-protein binding domains are located proximal to each other at the tip of the "scissors", might allow a concerted mode of substrate recognition while the opening/closing of the scissors might facilitate translocation.


    Organizational Affiliation

    Department of Biochemistry and Molecular Genetics, University of Alabama at Birmingham, 434 Kaul Genetics Building, 720 20(th) Street South, Birmingham, AL 35294, USA. dmitry@uab.edu



Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Preprotein translocase SecA subunit
A, B, C, D
997Thermus thermophilus HB8Mutation(s): 0 
Gene Names: secATTHA1251
Find proteins for Q5SIW3 (Thermus thermophilus (strain HB8 / ATCC 27634 / DSM 579))
Go to UniProtKB:  Q5SIW3
Protein Feature View
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.80 Å
  • R-Value Free: 0.255 
  • R-Value Work: 0.221 
  • R-Value Observed: 0.221 
  • Space Group: P 32
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 168.623α = 90
b = 168.623β = 90
c = 149.758γ = 120
Software Package:
Software NamePurpose
CrystalCleardata collection
MLPHAREphasing
CNSrefinement
HKL-2000data reduction
HKL-2000data scaling

Structure Validation

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Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2006-11-28
    Type: Initial release
  • Version 1.1: 2008-05-01
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Source and taxonomy, Version format compliance