PDBsum entry 2onk

Membrane protein

PDB id: 2onk

Contents

Protein chains

240 a.a. *

252 a.a. *

311 a.a. *

Ligands

PO4 ×4

WO4 ×2

Metals

_MG ×6

* Residue conservation analysis

PDB id:

2onk

Name:

Membrane protein

Title:

Abc transporter modbc in complex with its binding protein moda

Structure:

Molybdate/tungstate abc transporter, atp-binding protein. Chain: a, b, f, g. Synonym: cysa, af0092, modc. Engineered: yes. Molybdate/tungstate abc transporter, permease protein. Chain: c, d, h, i. Synonym: cyst, af0093, modb. Engineered: yes. Molybdate/tungstate binding protein.

Source:

Archaeoglobus fulgidus. Organism_taxid: 2234. Expressed in: escherichia coli. Expression_system_taxid: 562.

Resolution:

3.10Å R-factor: 0.256 R-free: 0.283

Authors:

K.Hollenstein,D.C.Frei,K.P.Locher

Key ref:

K.Hollenstein et al. (2007). Structure of an ABC transporter in complex with its binding protein. Nature, 446, 213-216. PubMed id: 17322901 DOI: 10.1038/nature05626

Date:

24-Jan-07 Release date: 06-Mar-07

Protein chains

O30144  (WTPC_ARCFU) -  Molybdate/tungstate import ATP-binding protein WtpC from Archaeoglobus fulgidus (strain ATCC 49558 / DSM 4304 / JCM 9628 / NBRC 100126 / VC-16)

Seq: 240 a.a.

Struc: 240 a.a.

Protein chains

O30143  (WTPB_ARCFU) -  Molybdate/tungstate transport system permease protein WtpB from Archaeoglobus fulgidus (strain ATCC 49558 / DSM 4304 / JCM 9628 / NBRC 100126 / VC-16)

Seq: 261 a.a.

Struc: 252 a.a.

Protein chains

O30142  (WTPA_ARCFU) -  Molybdate/tungstate-binding protein WtpA from Archaeoglobus fulgidus (strain ATCC 49558 / DSM 4304 / JCM 9628 / NBRC 100126 / VC-16)

Seq: 342 a.a.

Struc: 311 a.a.

Enzyme reactions

• Enzyme class: Chains A, B, F, G: E.C.7.3.2.6 - ABC-type tungstate transporter.
• Reaction: tungstate(in) + ATP + H2O = tungstate(out) + ADP + phosphate + H⁺

tungstate(in) + ATP + H2O = tungstate(out) + ADP + phosphate (Bound ligand (Het Group name = PO4) corresponds exactly) + H(+)

Molecule diagrams generated from .mol files obtained from the KEGG ftp site

reference

DOI no: 10.1038/nature05626

Nature 446:213-216 (2007)

PubMed id: 17322901

Structure of an ABC transporter in complex with its binding protein.

K.Hollenstein, D.C.Frei, K.P.Locher.

ABSTRACT

ATP-binding cassette (ABC) transporter proteins carry diverse substrates across cell membranes. Whereas clinically relevant ABC exporters are implicated in various diseases or cause multidrug resistance of cancer cells, bacterial ABC importers are essential for the uptake of nutrients, including rare elements such as molybdenum. A detailed understanding of their mechanisms requires direct visualization at high resolution and in distinct conformations. Our recent structure of the multidrug ABC exporter Sav1866 has revealed an outward-facing conformation of the transmembrane domains coupled to a closed conformation of the nucleotide-binding domains, reflecting the ATP-bound state. Here we present the 3.1 A crystal structure of a putative molybdate transporter (ModB2C2) from Archaeoglobus fulgidus in complex with its binding protein (ModA). Twelve transmembrane helices of the ModB subunits provide an inward-facing conformation, with a closed gate near the external membrane boundary. The ATP-hydrolysing ModC subunits reveal a nucleotide-free, open conformation, whereas the attached binding protein aligns the substrate-binding cleft with the entrance to the presumed translocation pathway. Structural comparison of ModB2C2A with Sav1866 suggests a common alternating access and release mechanism, with binding of ATP promoting an outward-facing conformation and dissociation of the hydrolysis products promoting an inward-facing conformation.

Selected figure(s)

Figure 1.
Figure 1: Overall structure. Front view of the ModB[2]C[2]A complex in ribbon representation, with the ModB subunits coloured yellow and blue, the ModC subunits coloured green and magenta, the binding protein ModA coloured red, and with bound tungstate in van der Waals representation (yellow and blue spheres). The grey box depicts the probable location of the lipid bilayer on the basis of the hydrophobicity of the protein surface. N, amino terminus; C, carboxy terminus. Note that there is a vertical two-fold molecular and non-crystallographic symmetry axis for ModB[2]C[2].

Figure 2.
Figure 2: ModB architecture and conserved gate regions. a, View from the extracellular side onto the transmembrane ModB subunits, with one subunit in yellow ribbon representation, the other as a blue backbone trace. Helices are numbered as in b, and conserved motifs forming the closed external gate are coloured green and red in both subunits. Relevant C positions are depicted as black spheres, with their residue numbers indicated. The conserved Phe 200 is shown in ball-and-stick representation. b, Topological scheme of the ModB subunit. Transmembrane helices are numbered consecutively, and short helices following a transmembrane helix additionally carry letters. The conserved gate regions are coloured as in a. c, Alignment of the A. fulgidus ModB sequence with those of other molybdate and sulphate ABC transporters (abbreviated species name is followed by an underscore and the ABC transporter name). Residues with significant conservation are shaded grey. Helices and conserved motifs are indicated above the sequences. Conserved gate regions are coloured as in a. TM, transmembrane.

The above figures are reprinted by permission from Macmillan Publishers Ltd: Nature (2007, 446, 213-216) copyright 2007.

Figures were selected by the author.