PDBsum entry 2nq2

Metal transport

PDB id: 2nq2

Contents

Protein chains

308 a.a. *

251 a.a. *

Waters ×682

* Residue conservation analysis

PDB id:

2nq2

Name:

Metal transport

Title:

An inward-facing conformation of a putative metal-chelate type abc transporter.

Structure:

Hypothetical abc transporter permease protein hi1471. Chain: a, b. Engineered: yes. Hypothetical abc transporter atp-binding protein hi1470. Chain: c, d. Engineered: yes

Source:

Haemophilus influenzae. Organism_taxid: 727. Strain: kw20 rd. Gene: hi_1471. Expressed in: escherichia coli. Expression_system_taxid: 562. Gene: hi_1470.

Resolution:

2.40Å R-factor: 0.222 R-free: 0.260

Authors:

H.P.Pinkett,A.T.Lee,P.Lum,K.P.Locher,D.C.Rees

Key ref:

H.W.Pinkett et al. (2007). An inward-facing conformation of a putative metal-chelate-type ABC transporter. Science, 315, 373-377. PubMed id: 17158291 DOI: 10.1126/science.1133488

Date:

30-Oct-06 Release date: 02-Jan-07

Protein chains

Q57130  (Y1471_HAEIN) -  Molybdate import system permease protein MolB from Haemophilus influenzae (strain ATCC 51907 / DSM 11121 / KW20 / Rd)

Seq: 337 a.a.

Struc: 308 a.a.

Protein chains

Q57399  (Y1470_HAEIN) -  Molybdate import ATP-binding protein MolC from Haemophilus influenzae (strain ATCC 51907 / DSM 11121 / KW20 / Rd)

Seq: 253 a.a.

Struc: 251 a.a.

Enzyme reactions

• Enzyme class 2: Chains A, B: E.C.?
• Enzyme class 3: Chains C, D: E.C.7.3.2.5 - ABC-type molybdate transporter.
• Reaction: molybdate(out) + ATP + H2O = molybdate(in) + ADP + phosphate + H⁺

Note, where more than one E.C. class is given (as above), each may correspond to a different protein domain or, in the case of polyprotein precursors, to a different mature protein.

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

reference

DOI no: 10.1126/science.1133488

Science 315:373-377 (2007)

PubMed id: 17158291

An inward-facing conformation of a putative metal-chelate-type ABC transporter.

H.W.Pinkett, A.T.Lee, P.Lum, K.P.Locher, D.C.Rees.

ABSTRACT

The crystal structure of a putative metal-chelate-type adenosine triphosphate (ATP)-binding cassette (ABC) transporter encoded by genes HI1470 and HI1471 of Haemophilus influenzae has been solved at 2.4 angstrom resolution. The permeation pathway exhibits an inward-facing conformation, in contrast to the outward-facing state previously observed for the homologous vitamin B12 importer BtuCD. Although the structures of both HI1470/1 and BtuCD have been solved in nucleotide-free states, the pairs of ABC subunits in these two structures differ by a translational shift in the plane of the membrane that coincides with a repositioning of the membrane-spanning subunits. The differences observed between these ABC transporters involve relatively modest rearrangements and may serve as structural models for inward- and outward-facing conformations relevant to the alternating access mechanism of substrate translocation.

Selected figure(s)

Figure 2.
Fig. 2. Visualization of the permeation pathways of HI1470/1 and BtuCD with the program HOLE (12). (A) The permeation pathway generated by the two HI1471 subunits is narrow at the periplasmic surface and open to the cytoplasm, which are located toward the top and bottom of the figure, respectively. (B) In contrast, the pathway for BtuC is closed at the cytoplasm and open to the periplasm. The HOLE representation of the pore surface is shown in a multicolored form that was displayed and rendered with the program VMD (33). Red, green, and blue surfaces designate regions of the permeation pathway with effective radii <0.6, 0.6 to 1.15, and >1.15 Å, respectively. The calculated diameters at the widest part of the pathways illustrated for HI1470/1 and BtuCD are 11 and 9 Å, respectively. The permeation pathway in BtuCD is of sufficient size to accommodate a corrin ring but not the entire B[12] molecule (9); the ligand for HI1470/1 has not been identified.

Figure 3.
Fig. 3. (A) Comparison of the homologous membrane-spanning subunits HI1471 and BtuC, after superposition of TM2 in subunit A (to the left) of each structure, as viewed down the molecular two-fold axis from the periplasm. With the exceptions of TM3 to TM5, the helices in the A subunits of HI1471 (cyan) and BtuC (purple) superimpose closely. In contrast, interconversion of the B subunits (to the right) between these two structures (blue and red, respectively) requires an 9° twist (indicated by the curved arrow) about an axis oriented in the direction shown to the right, which passes through the helical domain of the ABC subunit. (B) Stereoview of a superposition of helices TM3, TM4, TM5, TM8, TM10, and 5a in subunit A of HI1471 (cyan) and BtuC (purple), as viewed from within the permeation pathway with the molecular two-fold axis vertical. The internal symmetry–relating helices TM3 and TM8 and TM5 and TM10, as well as the irregular structures of TM3 and TM8, may be observed. The extramembrane helix 5a helps restrict the permeation pathway on the periplasmic side of HI1470/1.

The above figures are reprinted by permission from the AAAs: Science (2007, 315, 373-377) copyright 2007.

Figures were selected by an automated process.