Limits...
Structure and interdomain interactions of a hybrid domain: a disulphide-rich module of the fibrillin/LTBP superfamily of matrix proteins.

Jensen SA, Iqbal S, Lowe ED, Redfield C, Handford PA - Structure (2009)

Bottom Line: Here we present the crystal structure of a fibrillin-1 cbEGF9-hyb2-cbEGF10 fragment, solved to 1.8 A resolution.Pairwise interactions with neighboring cbEGF domains demonstrate extensive interfaces, with the hyb2-cbEGF10 interface dependent on Ca(2+) binding.These observations provide accurate constraints for models of fibrillin organization within the 10-12 nm microfibrils and provide further molecular insights into how Ca(2+) binding influences the intermolecular interactions and biomechanical properties of fibrillin-1.

View Article: PubMed Central - PubMed

Affiliation: Department of Biochemistry, University of Oxford, Oxford, UK.

ABSTRACT
The fibrillins and latent transforming growth factor-beta binding proteins (LTBPs) form a superfamily of structurally-related proteins consisting of calcium-binding epidermal growth factor-like (cbEGF) domains interspersed with 8-cysteine-containing transforming growth factor beta-binding protein-like (TB) and hybrid (hyb) domains. Fibrillins are the major components of the extracellular 10-12 nm diameter microfibrils, which mediate a variety of cell-matrix interactions. Here we present the crystal structure of a fibrillin-1 cbEGF9-hyb2-cbEGF10 fragment, solved to 1.8 A resolution. The hybrid domain fold is similar, but not identical, to the TB domain fold seen in previous fibrillin-1 and LTBP-1 fragments. Pairwise interactions with neighboring cbEGF domains demonstrate extensive interfaces, with the hyb2-cbEGF10 interface dependent on Ca(2+) binding. These observations provide accurate constraints for models of fibrillin organization within the 10-12 nm microfibrils and provide further molecular insights into how Ca(2+) binding influences the intermolecular interactions and biomechanical properties of fibrillin-1.

Show MeSH

Related in: MedlinePlus

Residues Involved in the Formation of Interdomain Interfaces(A and B) Residues involved in interdomain contacts were identified using the program Contact in the CCP4 program suite (CCP4, 1994), with a distance limit of 4 Å. Hyb domain residues at the cbEGF9-hyb2 interface (A) or hyb2-cbEGF10 interface (B) are indicated by magenta spheres and interacting cbEGF residues are indicated by green spheres.(C) An alignment of the hyb2 and TB4 domains shows similarities of the regions involved in interactions with either the N-terminal (red) or C-terminal (cyan) cbEGFs. Domains were aligned using Clustal W 2.0 (Larkin et al., 2007), and cysteines are highlighted in yellow.
© Copyright Policy
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC2724076&req=5

fig4: Residues Involved in the Formation of Interdomain Interfaces(A and B) Residues involved in interdomain contacts were identified using the program Contact in the CCP4 program suite (CCP4, 1994), with a distance limit of 4 Å. Hyb domain residues at the cbEGF9-hyb2 interface (A) or hyb2-cbEGF10 interface (B) are indicated by magenta spheres and interacting cbEGF residues are indicated by green spheres.(C) An alignment of the hyb2 and TB4 domains shows similarities of the regions involved in interactions with either the N-terminal (red) or C-terminal (cyan) cbEGFs. Domains were aligned using Clustal W 2.0 (Larkin et al., 2007), and cysteines are highlighted in yellow.

Mentions: An understanding of how adjacent domains in fibrillin interact is required to provide important constraints on how individual fibrillin molecules can be arranged within the microfibril. Previous studies have shown that Ca2+ plays an important role in the formation of interfaces within cbEGF-cbEGF and TB-cbEGF pairs, and confers a rigidity to these structures (Jensen et al., 2005; Kettle et al., 1999; Knott et al., 1996; Smallridge et al., 1999; Whiteman et al., 1998). To examine the interactions of domain hyb2, points of contact at the interdomain interfaces and buried surface areas of cbEGF9-hyb2-cbEGF10 were determined from the crystal structure using the programs Contact and AreaIMol in the CCP4 program suite (CCP4, 1994). Using a 4.0 Å maximum contact distance, residues in hyb2 found to interact with parts of cbEGF9 included Thr848, Ile849, Ser873, and Arg902 (Figure 4A). At the other side of the hyb2 domain, residues Ile866, Asn867, Ser877, Leu879, Gly899, and Tyr900 were found to be involved in interdomain contacts with cbEGF10 residues (Figure 4B). A comparison of the residues in hyb2 and TB4 that interact with the adjacent cbEGF domains (Figure 4C) shows that there are conserved patches of sequence that are involved in packing with either the N-terminal or C-terminal adjacent domain.


Structure and interdomain interactions of a hybrid domain: a disulphide-rich module of the fibrillin/LTBP superfamily of matrix proteins.

Jensen SA, Iqbal S, Lowe ED, Redfield C, Handford PA - Structure (2009)

Residues Involved in the Formation of Interdomain Interfaces(A and B) Residues involved in interdomain contacts were identified using the program Contact in the CCP4 program suite (CCP4, 1994), with a distance limit of 4 Å. Hyb domain residues at the cbEGF9-hyb2 interface (A) or hyb2-cbEGF10 interface (B) are indicated by magenta spheres and interacting cbEGF residues are indicated by green spheres.(C) An alignment of the hyb2 and TB4 domains shows similarities of the regions involved in interactions with either the N-terminal (red) or C-terminal (cyan) cbEGFs. Domains were aligned using Clustal W 2.0 (Larkin et al., 2007), and cysteines are highlighted in yellow.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2724076&req=5

fig4: Residues Involved in the Formation of Interdomain Interfaces(A and B) Residues involved in interdomain contacts were identified using the program Contact in the CCP4 program suite (CCP4, 1994), with a distance limit of 4 Å. Hyb domain residues at the cbEGF9-hyb2 interface (A) or hyb2-cbEGF10 interface (B) are indicated by magenta spheres and interacting cbEGF residues are indicated by green spheres.(C) An alignment of the hyb2 and TB4 domains shows similarities of the regions involved in interactions with either the N-terminal (red) or C-terminal (cyan) cbEGFs. Domains were aligned using Clustal W 2.0 (Larkin et al., 2007), and cysteines are highlighted in yellow.
Mentions: An understanding of how adjacent domains in fibrillin interact is required to provide important constraints on how individual fibrillin molecules can be arranged within the microfibril. Previous studies have shown that Ca2+ plays an important role in the formation of interfaces within cbEGF-cbEGF and TB-cbEGF pairs, and confers a rigidity to these structures (Jensen et al., 2005; Kettle et al., 1999; Knott et al., 1996; Smallridge et al., 1999; Whiteman et al., 1998). To examine the interactions of domain hyb2, points of contact at the interdomain interfaces and buried surface areas of cbEGF9-hyb2-cbEGF10 were determined from the crystal structure using the programs Contact and AreaIMol in the CCP4 program suite (CCP4, 1994). Using a 4.0 Å maximum contact distance, residues in hyb2 found to interact with parts of cbEGF9 included Thr848, Ile849, Ser873, and Arg902 (Figure 4A). At the other side of the hyb2 domain, residues Ile866, Asn867, Ser877, Leu879, Gly899, and Tyr900 were found to be involved in interdomain contacts with cbEGF10 residues (Figure 4B). A comparison of the residues in hyb2 and TB4 that interact with the adjacent cbEGF domains (Figure 4C) shows that there are conserved patches of sequence that are involved in packing with either the N-terminal or C-terminal adjacent domain.

Bottom Line: Here we present the crystal structure of a fibrillin-1 cbEGF9-hyb2-cbEGF10 fragment, solved to 1.8 A resolution.Pairwise interactions with neighboring cbEGF domains demonstrate extensive interfaces, with the hyb2-cbEGF10 interface dependent on Ca(2+) binding.These observations provide accurate constraints for models of fibrillin organization within the 10-12 nm microfibrils and provide further molecular insights into how Ca(2+) binding influences the intermolecular interactions and biomechanical properties of fibrillin-1.

View Article: PubMed Central - PubMed

Affiliation: Department of Biochemistry, University of Oxford, Oxford, UK.

ABSTRACT
The fibrillins and latent transforming growth factor-beta binding proteins (LTBPs) form a superfamily of structurally-related proteins consisting of calcium-binding epidermal growth factor-like (cbEGF) domains interspersed with 8-cysteine-containing transforming growth factor beta-binding protein-like (TB) and hybrid (hyb) domains. Fibrillins are the major components of the extracellular 10-12 nm diameter microfibrils, which mediate a variety of cell-matrix interactions. Here we present the crystal structure of a fibrillin-1 cbEGF9-hyb2-cbEGF10 fragment, solved to 1.8 A resolution. The hybrid domain fold is similar, but not identical, to the TB domain fold seen in previous fibrillin-1 and LTBP-1 fragments. Pairwise interactions with neighboring cbEGF domains demonstrate extensive interfaces, with the hyb2-cbEGF10 interface dependent on Ca(2+) binding. These observations provide accurate constraints for models of fibrillin organization within the 10-12 nm microfibrils and provide further molecular insights into how Ca(2+) binding influences the intermolecular interactions and biomechanical properties of fibrillin-1.

Show MeSH
Related in: MedlinePlus