1T5E

The structure of MexA

• PDB DOI: https://doi.org/10.2210/pdb1T5E/pdb

• Classification: TRANSPORT PROTEIN
• Organism(s): Pseudomonas aeruginosa
• Expression System: Escherichia coli
• Mutation(s): No 
• Membrane Protein: Yes  mpstruc


• Deposited: 2004-05-04 Released: 2004-05-18 
• Deposition Author(s): Higgins, M.K., Bokma, E., Koronakis, E., Hughes, C., Koronakis, V.

---

Experimental Data Snapshot

• Method: X-RAY DIFFRACTION
• Resolution: 3.00 Å
• R-Value Free: 0.285 
• R-Value Work: 0.273 
• R-Value Observed: 0.274 

Literature

Structure of the periplasmic component of a bacterial drug efflux pump

Higgins, M.K., Bokma, E., Koronakis, E., Hughes, C., Koronakis, V.

(2004) Proc Natl Acad Sci U S A 101: 9994-9999

• PubMed: 15226509 
• DOI: https://doi.org/10.1073/pnas.0400375101
• Primary Citation of Related Structures:  
  1T5E


• PubMed Abstract: 
  

  Multidrug resistance among Gram-negative bacteria is conferred by three-component membrane pumps that expel diverse antibiotics from the cell. These efflux pumps consist of an inner membrane transporter such as the AcrB proton antiporter, an outer membrane exit duct of the TolC family, and a periplasmic protein known as the adaptor. We present the x-ray structure of the MexA adaptor from the human pathogen Pseudomonas aeruginosa. The elongated molecule contains three linearly arranged subdomains; a 47-A-long alpha-helical hairpin, a lipoyl domain, and a six-stranded beta-barrel. In the crystal, hairpins of neighboring MexA monomers pack side-by-side to form twisted arcs. We discuss the implications of the packing of molecules within the crystal. On the basis of the structure and packing, we suggest a model for the key periplasmic interaction between the outer membrane channel and the adaptor protein in the assembled drug efflux pump.

---

Organizational Affiliation: 

Department of Pathology, Cambridge University, Tennis Court Road, Cambridge CB2 1QP, United Kingdom. [e-mail]

Biological Assembly 1  

Global Symmetry: Helical - H  (Explore in 3D)
Global Stoichiometry: Homo 13-mer - A13 

Biological assembly 1 assigned by authors and generated by PISA (software)

Macromolecule Content

• Total Structure Weight: 503.41 kDa 
• Atom Count: 23,101 
• Modelled Residue Count: 3,003 
• Deposited Residue Count: 4,680 
• Unique protein chains: 1

Macromolecules

Entity ID: 1
Molecule	Chains	Sequence Length	Organism	Details	Image
Multidrug resistance protein mexA	A, B, C, D, E, F, G, H, I, J, K, L, M	360	Pseudomonas aeruginosa	Mutation(s): 0  Gene Names: MEXA, PA0425 Membrane Entity: Yes
UniProt
Find proteins for P52477 (Pseudomonas aeruginosa (strain ATCC 15692 / DSM 22644 / CIP 104116 / JCM 14847 / LMG 12228 / 1C / PRS 101 / PAO1)) Explore P52477  Go to UniProtKB:  P52477

Small Molecules

Ligands 2 Unique
ID	Chains	Name / Formula / InChI Key	2D Diagram
GOL	N [auth A], O [auth B], W [auth J], Z [auth M]	GLYCEROL C3 H8 O3 PEDCQBHIVMGVHV-UHFFFAOYSA-N
3GR	P [auth C], Q [auth D], R [auth E], S [auth F], T [auth G], U [auth H], V [auth I], X [auth K], Y [auth L]	D-Glyceraldehyde C3 H6 O3 MNQZXJOMYWMBOU-VKHMYHEASA-N

Experimental Data & Validation

Experimental Data

• Method: X-RAY DIFFRACTION
• Resolution: 3.00 Å
• R-Value Free: 0.285 
• R-Value Work: 0.273 
• R-Value Observed: 0.274 
• Space Group: P 1 2₁ 1

Unit Cell:

Length ( Å )	Angle ( ˚ )
a = 130.551	α = 90
b = 183.585	β = 107.38
c = 213.314	γ = 90

Software Package:

Software Name	Purpose
MOSFLM	data reduction
SCALA	data scaling
SHARP	phasing
CNS	refinement
CCP4	data scaling

Structure Validation

Entry History 

Deposition Data

• Released Date: 2004-05-18 
Deposition Author(s): Higgins, M.K., Bokma, E., Koronakis, E., Hughes, C., Koronakis, V.

Revision History  

• Version 1.0: 2004-05-18
  Type: Initial release
  
• Version 1.1: 2008-04-30
  Changes: Version format compliance
• Version 1.2: 2011-07-13
  Changes: Non-polymer description, Version format compliance
• Version 2.0: 2020-07-08
  Changes: Atomic model, Data collection, Derived calculations, Structure summary