PDBsum entry 1a89

Extracellular matrix

PDB id: 1a89

Contents

Protein chains

21 a.a.

Theoretical model

PDB id:

1a89

Name:

Extracellular matrix

Title:

Molecular features of the collagen v heparin binding site theoretical model

Structure:

Homotrimer collagen [alpha 1(v)]3. Chain: a, b, c. Fragment: heparin binding domain. Engineered: yes. Biological_unit: trimer

Source:

Homo sapiens. Human. Expressed in: escherichia coli.

Authors:

F.Delacoux,A.Fichard,C.Geourjon,R.Garrone,F.Ruggiero

Key ref:

F.Delacoux et al. (1998). Molecular features of the collagen V heparin binding site. J Biol Chem, 273, 15069-15076. PubMed id: 9614116 DOI: 10.1074/jbc.273.24.15069

Date:

03-Apr-98 Release date: 21-Oct-98

Protein chains

P20908  (CO5A1_HUMAN) -  Collagen alpha-1(V) chain from Homo sapiens

Seq: 1838 a.a.

Struc: 21 a.a.

DOI no: 10.1074/jbc.273.24.15069

J Biol Chem 273:15069-15076 (1998)

PubMed id: 9614116

Molecular features of the collagen V heparin binding site.

F.Delacoux, A.Fichard, C.Geourjon, R.Garrone, F.Ruggiero.

ABSTRACT

A heparin binding region is known to be present within the triple helical part of the alpha1(V) chain. Here we show that a recombinant alpha1(V) fragment (Ile824 to Pro950), referred to as HepV, is sufficient for heparin binding at physiological ionic strength. Both native individual alpha1(V) chains and HepV are eluted at identical NaCl concentrations (0.35 M) from a heparin-Sepharose column, and this binding can be inhibited specifically by the addition of free heparin or heparan sulfate. In contrast, a shorter 23-residue synthetic peptide, containing the putative heparin binding site in HepV, fails to bind heparin. Interestingly, HepV promotes cell attachment, and HepV-mediated adhesion is inhibited specifically by heparin or heparan sulfate, indicating that this region might behave as an adhesive binding site. The same site is equally functional on triple helical molecules as shown by heparin-gold labeling. However, the affinities for heparin of each of the collagen V molecular forms tested are different and increase with the number of alpha1(V) chains incorporated in the molecules. Molecular modeling of a sequence encompassing the putative HepV binding sequence region shows that all of the basic residues cluster on one side of the helical face. A highly positively charged ring around the molecule is thus particularly evident for the alpha1(V) homotrimer. This could strengthen its interaction with the anionic heparin molecules. We propose that a single heparin binding site is involved in heparin-related glycosaminoglycans-collagen V interactions, but the different affinities observed likely modulate cell and matrix interactions between collagen V and heparan sulfate proteoglycans in tissues.

Selected figure(s)

Figure 1.
Fig. 1. Scheme of the primary structure of 1(V) chain and design of recombinant fragments. 1TH corresponds to the recombinant triple helical 1(V) COL1 domain overexpressed in mammalian cells (14), HepV corresponds to a portion of the COL1 domain of the 1(V) chain produced in E. coli, and the synthetic peptide HepP to a portion of HepV (the arrow indicates the endoproteinase Glu-C cleavage site, according to Yaoi et al. (15). COL, collagenous domain; NC, non-collagenous domain; numbers at the beginning and end of each fragments refer to amino acid residues.

Figure 5.
Fig. 5. Electron microscopy images of pepsinized [ 1(V)][2] 2(V) heterotrimer (panel A) and of truncated recombinant [ 1(V)][3] homotrimer (panel B) heparin-gold complexes observed by rotary shadowing. Panel C, mapping of the heparin-gold location on the 300-nm-long triple helical domain of collagen V molecules referred to as COL1 (upper panel) and on the truncated recombinant homotrimer (lower panel).

The above figures are reprinted by permission from the ASBMB: J Biol Chem (1998, 273, 15069-15076) copyright 1998.

Figures were selected by an automated process.