PDBsum entry 1kmh

Hydrolase

PDB id: 1kmh

Contents

Protein chains

477 a.a. *

467 a.a. *

Ligands

TTX

* Residue conservation analysis

References listed in PDB file

Key reference

Title

Structure of spinach chloroplast f1-Atpase complexed with the phytopathogenic inhibitor tentoxin.

Author

G.Groth.

Ref.

Proc Natl Acad Sci U S A, 2002, 99, 3464-3468. [DOI no: 10.1073/pnas.052546099]

PubMed id

11904410

Abstract

Tentoxin, a natural cyclic tetrapeptide produced by phytopathogenic fungi from the Alternaria species affects the catalytic function of the chloroplast F(1)-ATPase in certain sensitive species of plants. In this study, we show that the uncompetitive inhibitor tentoxin binds to the alphabeta-interface of the chloroplast F(1)-ATPase in a cleft localized at betaAsp-83. Most of the binding site is located on the noncatalytic alpha-subunit. The crystal structure of the tentoxin-inhibited CF(1)-complex suggests that the inhibitor is hydrogen bonded to Asp-83 in the catalytic beta-subunit but forms hydrophobic contacts with residues Ile-63, Leu-65, Val-75, Tyr-237, Leu-238, and Met-274 in the adjacent alpha-subunit. Except for minor changes around the tentoxin-binding site, the structure of the chloroplast alpha(3)beta(3)-core complex is the same as that determined with the native chloroplast ATPase. Tentoxin seems to act by inhibiting inter-subunit contacts at the alphabeta-interface and by blocking the interconversion of binding sites in the catalytic mechanism.

Figure 2.
Fig. 2. Location of tentoxin in the crystal structure of the chloroplast F[1]-ATPase. (A) Ribbon diagram of the structure of the chloroplast -subunit (blue) and -subunit (red) at the tentoxin-binding site. The inhibitor is shown in ball-and-stick representation. Both subunits are shown with their 3-fold crystallographic axis in vertical orientation, with the binding site facing the external medium. (B) Schematic representation of the molecular structure of a single chloroplast -pair. The structure is shown from the top as it would appear on the membrane; the 3-fold axis points toward the viewer. The bound inhibitory tentoxin molecule is drawn in cpk mode.

Figure 3.
Fig. 3. Comparison of different conformational states of the bovine mitochondrial - and -subunits to the chloroplast -complex containing tentoxin. (A) Schematic representation of the peptide backbone of three different conformations of the mitochondrial - and -subunits that represent different states of the catalytic cycle (12, 30). Both subunits were superimposed on their C[ ]-atoms. The [E], [DP], and [TP] states of the noncatalytic -subunit is shown in gray, the closed conformation of the catalytic -subunit ( [DP] and [TP]) is drawn in red, and the open [E]state is coloured in green. Positions of residues Arg-304 and Glu-67, equivalent to residues Arg-297 and Asp-83 that are arrested by the tentoxin molecule in the chloroplast structure (B), are indicated by red and black arrows, respectively. As indicated by the arrow on the right (A), a shift form the closed to the open conformation of the catalytic -subunit which occurs during the catalytic cycle is associated with a domain movement that involves the -interface at Arg-304- Glu-67.

Secondary reference #1

Title

The structure of the chloroplast f1-Atpase at 3.2 a resolution.

Authors

G.Groth, E.Pohl.

Ref.

J Biol Chem, 2001, 276, 1345-1352. [DOI no: 10.1074/jbc.M008015200]

PubMed id

11032839

Figure 5.
Fig. 5. Schematic representation of the N-terminal six-stranded -barrel domain of the -subunit in the mitochondrial (A), chloroplast (B), and thermophilic ATPase (C).

Figure 7.
Fig. 7. Suggested potential Tentoxin binding site of the chloroplast ATPase (A) and corresponding domains in the mitochondrial (B) and thermophilic F[1] complex (C). Surface representation of residues within 20.0 Å of the essential Asp83 in CF[1] and the corresponding residues Asp67 in MF[1] and Asp68 in TF[1]. Structures are shown in stereo view with the crystallographic axis in the vertical position as they would appear from the outside of the [3] [3] complex.

The above figures are reproduced from the cited reference with permission from the ASBMB