4UAQ

Crystal structure of the accessory translocation ATPase, SecA2, from Mycobacterium tuberculosis


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.80 Å
  • R-Value Free: 0.281 
  • R-Value Work: 0.211 
  • R-Value Observed: 0.215 

wwPDB Validation   3D Report Full Report


This is version 1.2 of the entry. See complete history


Literature

Structural Similarities and Differences between Two Functionally Distinct SecA Proteins, Mycobacterium tuberculosis SecA1 and SecA2.

Swanson, S.Ioerger, T.R.Rigel, N.W.Miller, B.K.Braunstein, M.Sacchettini, J.C.

(2015) J Bacteriol 198: 720-730

  • DOI: https://doi.org/10.1128/JB.00696-15
  • Primary Citation of Related Structures:  
    4UAQ

  • PubMed Abstract: 

    While SecA is the ATPase component of the major bacterial secretory (Sec) system, mycobacteria and some Gram-positive pathogens have a second paralog, SecA2. In bacteria with two SecA paralogs, each SecA is functionally distinct, and they cannot compensate for one another. Compared to SecA1, SecA2 exports a distinct and smaller set of substrates, some of which have roles in virulence. In the mycobacterial system, some SecA2-dependent substrates lack a signal peptide, while others contain a signal peptide but possess features in the mature protein that necessitate a role for SecA2 in their export. It is unclear how SecA2 functions in protein export, and one open question is whether SecA2 works with the canonical SecYEG channel to export proteins. In this study, we report the structure of Mycobacterium tuberculosis SecA2 (MtbSecA2), which is the first structure of any SecA2 protein. A high level of structural similarity is observed between SecA2 and SecA1. The major structural difference is the absence of the helical wing domain, which is likely to play a role in how MtbSecA2 recognizes its unique substrates. Importantly, structural features critical to the interaction between SecA1 and SecYEG are preserved in SecA2. Furthermore, suppressor mutations of a dominant-negative secA2 mutant map to the surface of SecA2 and help identify functional regions of SecA2 that may promote interactions with SecYEG or the translocating polypeptide substrate. These results support a model in which the mycobacterial SecA2 works with SecYEG.


  • Organizational Affiliation

    Department of Biochemistry & Biophysics, Texas A&M University, College Station, Texas, USA.


Macromolecules
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Protein translocase subunit SecA 2778Mycobacterium tuberculosis H37RvMutation(s): 0 
Gene Names: secA2Rv1821MTCY1A11.22c
UniProt
Find proteins for P9WGP3 (Mycobacterium tuberculosis (strain ATCC 25618 / H37Rv))
Explore P9WGP3 
Go to UniProtKB:  P9WGP3
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP9WGP3
Sequence Annotations
Expand
  • Reference Sequence
Small Molecules
Modified Residues  1 Unique
IDChains TypeFormula2D DiagramParent
MSE
Query on MSE
A
L-PEPTIDE LINKINGC5 H11 N O2 SeMET
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.80 Å
  • R-Value Free: 0.281 
  • R-Value Work: 0.211 
  • R-Value Observed: 0.215 
  • Space Group: P 1 21 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 39.6α = 90
b = 162.09β = 95.87
c = 67.31γ = 90
Software Package:
Software NamePurpose
BUSTERrefinement
HKL-2000data reduction
HKL-2000data scaling
SHARPphasing

Structure Validation

View Full Validation Report



Entry History & Funding Information

Deposition Data


Funding OrganizationLocationGrant Number
NIH/NIAIDUnited StatesNIHP01AI095208

Revision History  (Full details and data files)

  • Version 1.0: 2015-09-09
    Type: Initial release
  • Version 1.1: 2016-01-13
    Changes: Database references
  • Version 1.2: 2016-02-10
    Changes: Database references