PDBsum entry 1okq

Metal binding protein

PDB id: 1okq

Contents

Protein chain

374 a.a. *

Metals

_CA

Waters ×38

* Residue conservation analysis

PDB id:

1okq

Name:

Metal binding protein

Title:

Laminin alpha 2 chain lg4-5 domain pair, ca1 site mutant

Structure:

Laminin alpha 2 chain. Chain: a. Fragment: laminin g-like domain 4-5 pair, residues 2729-3093. Engineered: yes. Mutation: yes

Source:

Mus musculus. Mouse. Organism_taxid: 10090. Strain: fvb/n. Cell_line: ebna-293. Tissue: embryo. Cell: emryonic kidney cell. Expressed in: homo sapiens. Expression_system_taxid: 9606.

Resolution:

2.80Å R-factor: 0.220 R-free: 0.270

Authors:

H.Wizemann,J.H.O.Garbe,M.V.K.Friedrich,R.Timpl,T.Sasaki,E.Hohenester

Key ref:

H.Wizemann et al. (2003). Distinct requirements for heparin and alpha-dystroglycan binding revealed by structure-based mutagenesis of the laminin alpha2 LG4-LG5 domain pair. J Mol Biol, 332, 635-642. PubMed id: 12963372 DOI: 10.1016/S0022-2836(03)00848-9

Date:

28-Jul-03 Release date: 11-Sep-03

Protein chain

Q60675  (LAMA2_MOUSE) -  Laminin subunit alpha-2 from Mus musculus

Seq: 3118 a.a.

Struc: 374 a.a.*

* PDB and UniProt seqs differ at 3 residue positions (black crosses)

DOI no: 10.1016/S0022-2836(03)00848-9

J Mol Biol 332:635-642 (2003)

PubMed id: 12963372

Distinct requirements for heparin and alpha-dystroglycan binding revealed by structure-based mutagenesis of the laminin alpha2 LG4-LG5 domain pair.

H.Wizemann, J.H.Garbe, M.V.Friedrich, R.Timpl, T.Sasaki, E.Hohenester.

ABSTRACT

Laminin-2 (alpha2beta1gamma1) is found in basement membranes surrounding muscle and peripheral nerve cells. Several types of cellular receptors bind to the laminin G-like (LG) domains at the C terminus of the alpha2 chain, the interaction with alpha-dystroglycan (alpha-DG) being particularly important in muscle. We have used site-directed mutagenesis and in vitro binding assays to map the binding sites on the laminin alpha2 chain LG4-LG5 domain pair for alpha-DG, heparin and sulfatides. Calcium-dependent alpha-DG recognition requires the calcium ion in LG4, but not the one in LG5, as well as basic residues in both LG domains. Heparin and sulfatides also bind to basic residues in both LG domains, but there is little overlap in the binding sites for alpha-DG and heparin/sulfatides. The results should prove useful for the molecular dissection of laminin-receptor interactions in vivo.

Selected figure(s)

Figure 1.
Figure 1. (a) Electrostatic surface representation of the laminin a2 LG4-LG5 structure.[14.] Positive and negative potential are represented by blue and red colouring, respectively. The Figure was made with GRASP. [31.] (b) Ca trace of the laminin a2 LG4-LG5 structure in the same orientation, with amino acid side-chains mutated in the present study shown as ball-and-stick models. Basic and acidic residues are coloured blue and red, respectively, and calcium ions are shown as pink spheres. The Figure was made with BOBSCRIPT [32.] and RASTER3D. [33.]

Figure 4.
Figure 4. Stereoview of the mutated calcium binding site in the laminin a2 LG4-LG5 D2808A/D2876A mutant. The wild-type structure is superimposed for comparison and shown in light blue. The F[obs] -F[calc] difference electron density map is shown in green at the +3s level.

The above figures are reprinted by permission from Elsevier: J Mol Biol (2003, 332, 635-642) copyright 2003.

Figures were selected by an automated process.