PDBsum entry 1iu2

Neuropeptide

PDB id: 1iu2

Contents

Protein chain

91 a.a. *

* Residue conservation analysis

PDB id:

1iu2

Name:

Neuropeptide

Title:

The first pdz domain of psd-95

Structure:

Psd-95. Chain: a. Fragment: pdz1 domain. Synonym: presynaptic density protein 95. Engineered: yes

Source:

Rattus norvegicus. Norway rat. Organism_taxid: 10116. Expressed in: escherichia coli. Expression_system_taxid: 562

NMR struc:

50 models

Authors:

J.-F.Long,H.Tochio,P.Wang,C.Sala,M.Niethammer,M.Sheng,M.Zhang

Key ref:

J.F.Long et al. (2003). Supramodular structure and synergistic target binding of the N-terminal tandem PDZ domains of PSD-95. J Mol Biol, 327, 203-214. PubMed id: 12614619 DOI: 10.1016/S0022-2836(03)00113-X

Date:

19-Feb-02 Release date: 11-Mar-03

Protein chain

P31016  (DLG4_RAT) -  Disks large homolog 4 from Rattus norvegicus

Seq: 724 a.a.

Struc: 91 a.a.

Enzyme reactions

• Enzyme class: E.C.?

DOI no: 10.1016/S0022-2836(03)00113-X

J Mol Biol 327:203-214 (2003)

PubMed id: 12614619

Supramodular structure and synergistic target binding of the N-terminal tandem PDZ domains of PSD-95.

J.F.Long, H.Tochio, P.Wang, J.S.Fan, C.Sala, M.Niethammer, M.Sheng, M.Zhang.

ABSTRACT

PDZ domain proteins play critical roles in binding, clustering and subcellular targeting of membrane receptors and ion channels. PDZ domains in multi-PDZ proteins often are arranged in groups with highly conserved spacing and intervening sequences; however, the functional significance of such tandem arrangements of PDZs is unclear. We have solved the three-dimensional structure of the first two PDZ domains of postsynaptic density protein-95 (PSD-95 PDZ1 and PDZ2), which are closely linked to each other in the PSD-95 family of scaffold proteins. The two PDZs have limited freedom of rotation and their C-terminal peptide-binding grooves are aligned with each other with an orientation preference for binding to pairs of C termini extending in the same direction. Increasing the spacing between PDZ1 and PDZ2 resulted in decreased binding between PDZ12 and its dimeric targets. The same mutation impaired the functional ability of PSD-95 to cluster Kv1.4 potassium channels in heterologous cells. The data presented provide a molecular basis for preferential binding of PSD-95 to multimeric membrane proteins with appropriate C-terminal sequences.

Selected figure(s)

Figure 1.
Figure 1. Structure of PSD-95 PDZ1 determined by NMR spectroscopy. (A) Stereoview showing the best-fit superposition of the backbone atoms (N, C^a, and C') of the final 20 structures of PSD-95 PDZ1. The structures are superimposed against the average structure using the residues 64-148. The structural statistics are summarized in Table 1. (B) Ribbon diagram presentation of PSD-95 PDZ1. The secondary structure elements are labelled following the scheme used in the crystal structure of PSD-95 PDZ3. [7] (C) Comparison of the 3D structures of PDZ1 and PDZ2 of PSD-95. The backbone traces (N, C^a, and C') of PDZ1 (gold) and PDZ2 (yellow) are superimposed. The two structures were fit to each other by excluding the GLGF-loop, bB/bC loop and the two termini. The rmsd between the backbones of the two PDZ domains is 1.35 Å.

Figure 5.
Figure 5. Functional role of conformation-restrained tandem PDZ repeats in PSD-95. (A) Extending the PDZ12 linker by introducing flexible amino acid residues reduces the size of the Kv1.4 channel clusters mediated by N-PDZ12. Myc-tagged constructs N-PDZ1-2 wild-type (N-PDZ12), the deletion mutant of N-PDZ12 (N-PDZ12Del) and the insertion mutant of N-PDZ12 (N-PDZ1-2Ins) were co-transfected in COS7 cells with potassium channel subunit Kv1.4. Cells cotransfected with different constructs, as indicated, were fixed two days after transfection and stained with Kv1.4 antibodies to visualize the potassium channel clusters. The schematics of the deletions and insertion mutations used in this study are shown. Insets show higher-magnification views of Kv1.4 clusters. (B) Frequency distribution (left) and mean values (right) of Kv1.4 cluster areas mediated by N-PDZ12, N-PDZ12(Del) and N-PDZ12(Ins), measured from at least ten cells for each construct. The scale bars represent 5 µm or 15 µm for the insets. An asterisk (*) indicates significance at p <0.01 in an unpaired, two-tailed Student's t-test.

The above figures are reprinted by permission from Elsevier: J Mol Biol (2003, 327, 203-214) copyright 2003.

Figures were selected by an automated process.