PDBsum entry 1oxx

Transport protein

PDB id: 1oxx

Contents

Protein chain

352 a.a. *

Metals

IOD ×32

Waters ×696

* Residue conservation analysis

PDB id:

1oxx

Name:

Transport protein

Title:

Crystal structure of glcv, the abc-atpase of the glucose abc transporter from sulfolobus solfataricus

Structure:

Abc transporter, atp binding protein. Chain: k. Synonym: glcv, glucose. Engineered: yes. Mutation: yes

Source:

Sulfolobus solfataricus. Organism_taxid: 2287. Gene: glcv. Expressed in: escherichia coli. Expression_system_taxid: 562.

Resolution:

1.45Å R-factor: 0.174 R-free: 0.213

Authors:

G.Verdon,S.-V.Albers,N.Van Oosterwijk,B.W.Dijkstra,A.J.M.Driessen, A.M.W.H.Thunnissen

Key ref:

G.Verdon et al. (2003). Formation of the productive ATP-Mg2+-bound dimer of GlcV, an ABC-ATPase from Sulfolobus solfataricus. J Mol Biol, 334, 255-267. PubMed id: 14607117 DOI: 10.1016/j.jmb.2003.08.065

Date:

03-Apr-03 Release date: 30-Sep-03

Protein chain

Q97UY8  (Q97UY8_SULSO) -  Glucose import ATP-binding protein GlcV from Saccharolobus solfataricus (strain ATCC 35092 / DSM 1617 / JCM 11322 / P2)

Seq: 353 a.a.

Struc: 352 a.a.*

* PDB and UniProt seqs differ at 1 residue position (black cross)

Enzyme reactions

• Enzyme class: E.C.7.5.2.- - ?????

DOI no: 10.1016/j.jmb.2003.08.065

J Mol Biol 334:255-267 (2003)

PubMed id: 14607117

Formation of the productive ATP-Mg2+-bound dimer of GlcV, an ABC-ATPase from Sulfolobus solfataricus.

G.Verdon, S.V.Albers, N.van Oosterwijk, B.W.Dijkstra, A.J.Driessen, A.M.Thunnissen.

ABSTRACT

The ABC-ATPase GlcV from Sulfolobus solfataricus energizes an ABC transporter mediating glucose uptake. In ABC transporters, two ABC-ATPases are believed to form a head-to-tail dimer, with both monomers contributing conserved residues to each of the two productive active sites. In contrast, isolated GlcV, although active, behaves apparently as a monomer in the presence of ATP-Mg(2+), AMPPNP-Mg(2+) or ATP alone. To resolve the oligomeric state of the active form of GlcV, we analysed the effects of changing the putative catalytic base, residue E166, into glutamine or alanine. Both mutants are, to different extents, defective in ATP hydrolysis, and gel-filtration experiments revealed their dimerization in the presence of ATP-Mg(2+). Mutant E166Q forms dimers also in the presence of ATP alone, without Mg(2+), whereas dimerization of mutant E166A requires both ATP and Mg(2+). These results confirm earlier reports for other ABC-ATPases, but for the first time suggest the occurrence of a fast equilibrium between ATP-bound monomers and ATP-bound dimers. We further mutated two highly conserved residues of the ABC signature motif, S142 and G144, into alanine. The G144A mutant is completely inactive and fails to dimerize, indicating an essential role of this residue in stabilizing the productive dimeric state. Mutant S142A retained considerable activity, and was able to dimerize, thus implying that the interaction of the serine with ATP is not essential for dimerization and catalysis. Furthermore, although the E166A and G144A mutants each alone are inactive, they produce an active heterodimer, showing that disruption of one active site can be tolerated. Our data suggest that ABC-ATPases with partially degenerated catalytic machineries, as they occur in vivo, can still form productive dimers to drive transport.

Selected figure(s)

Figure 6.
Figure 6. A, Model of a head-to-tail, ATP-Mg2+-bound dimer of GlcV. This structure was built by homology modelling at the SWISS-MODEL server (http://swissmodel.expasy.org/SWISS-MODEL.html) using as a template the structure of the ATP-Na^+-bound, LolD dimer.[21.] The locations of conserved motifs are indicated with colours, as in Figure 1. The nucleotide and Mg2+ are shown in ball-and-stick representation. B, Stereo view of one of the two active sites in the model of the ATP-Mg2+-bound dimer of GlcV. Residue side-chains, the nucleotide, the Mg2+ and its coordinating water molecules are shown in ball-and-stick representation. The extra methyl group in the G144A mutant is shown in cyan, as inferred from the GlcV-G144A crystal structure, revealing a steric clash with the oxygen atoms of the g-phosphate group and the side-chain of S40 (lines indicate the close contacts at 2.3 Å and 1.8 Å, respectively).

Figure 7.
Figure 7. Proposed mechanism of ATP hydrolysis catalyzed by GlcV.

The above figures are reprinted by permission from Elsevier: J Mol Biol (2003, 334, 255-267) copyright 2003.

Figures were selected by an automated process.