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The structure of the Ca²+-binding, glycosylated F-spondin domain of F-spondin - A C2-domain variant in an extracellular matrix protein.

Tan K, Lawler J - BMC Struct. Biol. (2011)

Bottom Line: The FS domain is found in F-spondins, mindins, M-spondin and amphiF-spondin.The unique feature of F-spondin FS domain is the presence of three disulfide bonds associated with the N- and C-termini of the domain and a highly conserved N-linked glycosylation site.The integrin-binding motif found in mindin is not conserved in the F-spondin FS domain.

View Article: PubMed Central - HTML - PubMed

Affiliation: Midwest Center for Structural Genomics and Structural Biology Center, Biosciences Division, Argonne National Laboratory, Argonne, IL 60439, USA. ktan@anl.gov

ABSTRACT

Background: F-spondin is a multi-domain extracellular matrix (ECM) protein and a contact-repellent molecule that directs axon outgrowth and cell migration during development. The reelin_N domain and the F-spondin domain (FS domain) comprise a proteolytic fragment that interacts with the cell membrane and guides the projection of commissural axons to floor plate. The FS domain is found in F-spondins, mindins, M-spondin and amphiF-spondin.

Results: We present the crystal structure of human F-spondin FS domain at 1.95Å resolution. The structure reveals a Ca2+-binding C2 domain variant with an 8-stranded antiparallel β-sandwich fold. Though the primary sequences of the FS domains of F-spondin and mindin are less than 36% identical, their overall structures are very similar. The unique feature of F-spondin FS domain is the presence of three disulfide bonds associated with the N- and C-termini of the domain and a highly conserved N-linked glycosylation site. The integrin-binding motif found in mindin is not conserved in the F-spondin FS domain.

Conclusion: The structure of the F-spondin FS domain completes the structural studies of the multiple-domain ECM molecule. The homology of its core structure to a common Ca2+- and lipid-binding C2 domain suggests that the F-spondin FS domain may be responsible for part of the membrane targeting of F-spondin in its regulation of axon development. The structural properties of the FS domain revealed in this study pave the way for further exploration into the functions of F-spondin.

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Multiple sequence alignment of FS domains from proteins across different species. Based on the FS domain structures of the two monomers, the secondary structures are indicated with arrows (β-strands) and coils (α-helices) above the appropriate sequences. Identical residues are highlighted in red. Disulfide bond forming cysteines are indicated with green numbers. Disulfide bond substitution, potential hydrogen bond forming residues (T190 and Q330) in amphiF-spondin are colored in blue. The integrin-binding LEV triplet found in human, mouse and rat mindins are highlighted in magenta. The sequences used in the alignment include human F-spondin (gi:110347423), rat F-spondin (gi:544353), chicken F-spondin (gi:45382337), Xenopus F-spondin (gi:544354), zebrafish F-spondin-1 (gi:18859413), zebrafish F-spondin-2 (gi:2529227), amphiF-spondin (gi:3319874), Drosophila melanogaster F-spondin (gi: 19922086), human mindin (gi: 52783469), mouse mindin (gi: 52783454, rat mindin (gi: 52783424) and zebrafish mindin-1 and -2 (gi: 82069286 and gi: 82069288). The alignment was generated with the program MultAlin[38] and ESPript[39]. In Drosophila melanogaster F-spondin (D. M-spondin), the large, likely unstructured, Ser, Gly, Thr and Ala-rich insertion (VQMQLQSQMQAGKSPSGGISSGTTSFNATAASTATPTGGSGGSGGSGGSGGTGTTTAE) between α3 and β2 is not shown in the alignment.
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Figure 4: Multiple sequence alignment of FS domains from proteins across different species. Based on the FS domain structures of the two monomers, the secondary structures are indicated with arrows (β-strands) and coils (α-helices) above the appropriate sequences. Identical residues are highlighted in red. Disulfide bond forming cysteines are indicated with green numbers. Disulfide bond substitution, potential hydrogen bond forming residues (T190 and Q330) in amphiF-spondin are colored in blue. The integrin-binding LEV triplet found in human, mouse and rat mindins are highlighted in magenta. The sequences used in the alignment include human F-spondin (gi:110347423), rat F-spondin (gi:544353), chicken F-spondin (gi:45382337), Xenopus F-spondin (gi:544354), zebrafish F-spondin-1 (gi:18859413), zebrafish F-spondin-2 (gi:2529227), amphiF-spondin (gi:3319874), Drosophila melanogaster F-spondin (gi: 19922086), human mindin (gi: 52783469), mouse mindin (gi: 52783454, rat mindin (gi: 52783424) and zebrafish mindin-1 and -2 (gi: 82069286 and gi: 82069288). The alignment was generated with the program MultAlin[38] and ESPript[39]. In Drosophila melanogaster F-spondin (D. M-spondin), the large, likely unstructured, Ser, Gly, Thr and Ala-rich insertion (VQMQLQSQMQAGKSPSGGISSGTTSFNATAASTATPTGGSGGSGGSGGSGGTGTTTAE) between α3 and β2 is not shown in the alignment.

Mentions: The residues contributing to the hydrophobic core of the FS domain are A205, Y207, L209 and F211 of the β1 strand, I234 of the β2 strand, F305 and V307 of the β4 strand, M314 and F316 of the β5 strand, as well as A401, V403 and I405 of the β8 strand (Figure 4). Based on the sequence conservation of these residues among FS domains of F-spondins, mindins, M-spondin as well as AmphiF-spondin, we predict that a C2 domain core structure should be conserved in these proteins.


The structure of the Ca²+-binding, glycosylated F-spondin domain of F-spondin - A C2-domain variant in an extracellular matrix protein.

Tan K, Lawler J - BMC Struct. Biol. (2011)

Multiple sequence alignment of FS domains from proteins across different species. Based on the FS domain structures of the two monomers, the secondary structures are indicated with arrows (β-strands) and coils (α-helices) above the appropriate sequences. Identical residues are highlighted in red. Disulfide bond forming cysteines are indicated with green numbers. Disulfide bond substitution, potential hydrogen bond forming residues (T190 and Q330) in amphiF-spondin are colored in blue. The integrin-binding LEV triplet found in human, mouse and rat mindins are highlighted in magenta. The sequences used in the alignment include human F-spondin (gi:110347423), rat F-spondin (gi:544353), chicken F-spondin (gi:45382337), Xenopus F-spondin (gi:544354), zebrafish F-spondin-1 (gi:18859413), zebrafish F-spondin-2 (gi:2529227), amphiF-spondin (gi:3319874), Drosophila melanogaster F-spondin (gi: 19922086), human mindin (gi: 52783469), mouse mindin (gi: 52783454, rat mindin (gi: 52783424) and zebrafish mindin-1 and -2 (gi: 82069286 and gi: 82069288). The alignment was generated with the program MultAlin[38] and ESPript[39]. In Drosophila melanogaster F-spondin (D. M-spondin), the large, likely unstructured, Ser, Gly, Thr and Ala-rich insertion (VQMQLQSQMQAGKSPSGGISSGTTSFNATAASTATPTGGSGGSGGSGGSGGTGTTTAE) between α3 and β2 is not shown in the alignment.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
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Figure 4: Multiple sequence alignment of FS domains from proteins across different species. Based on the FS domain structures of the two monomers, the secondary structures are indicated with arrows (β-strands) and coils (α-helices) above the appropriate sequences. Identical residues are highlighted in red. Disulfide bond forming cysteines are indicated with green numbers. Disulfide bond substitution, potential hydrogen bond forming residues (T190 and Q330) in amphiF-spondin are colored in blue. The integrin-binding LEV triplet found in human, mouse and rat mindins are highlighted in magenta. The sequences used in the alignment include human F-spondin (gi:110347423), rat F-spondin (gi:544353), chicken F-spondin (gi:45382337), Xenopus F-spondin (gi:544354), zebrafish F-spondin-1 (gi:18859413), zebrafish F-spondin-2 (gi:2529227), amphiF-spondin (gi:3319874), Drosophila melanogaster F-spondin (gi: 19922086), human mindin (gi: 52783469), mouse mindin (gi: 52783454, rat mindin (gi: 52783424) and zebrafish mindin-1 and -2 (gi: 82069286 and gi: 82069288). The alignment was generated with the program MultAlin[38] and ESPript[39]. In Drosophila melanogaster F-spondin (D. M-spondin), the large, likely unstructured, Ser, Gly, Thr and Ala-rich insertion (VQMQLQSQMQAGKSPSGGISSGTTSFNATAASTATPTGGSGGSGGSGGSGGTGTTTAE) between α3 and β2 is not shown in the alignment.
Mentions: The residues contributing to the hydrophobic core of the FS domain are A205, Y207, L209 and F211 of the β1 strand, I234 of the β2 strand, F305 and V307 of the β4 strand, M314 and F316 of the β5 strand, as well as A401, V403 and I405 of the β8 strand (Figure 4). Based on the sequence conservation of these residues among FS domains of F-spondins, mindins, M-spondin as well as AmphiF-spondin, we predict that a C2 domain core structure should be conserved in these proteins.

Bottom Line: The FS domain is found in F-spondins, mindins, M-spondin and amphiF-spondin.The unique feature of F-spondin FS domain is the presence of three disulfide bonds associated with the N- and C-termini of the domain and a highly conserved N-linked glycosylation site.The integrin-binding motif found in mindin is not conserved in the F-spondin FS domain.

View Article: PubMed Central - HTML - PubMed

Affiliation: Midwest Center for Structural Genomics and Structural Biology Center, Biosciences Division, Argonne National Laboratory, Argonne, IL 60439, USA. ktan@anl.gov

ABSTRACT

Background: F-spondin is a multi-domain extracellular matrix (ECM) protein and a contact-repellent molecule that directs axon outgrowth and cell migration during development. The reelin_N domain and the F-spondin domain (FS domain) comprise a proteolytic fragment that interacts with the cell membrane and guides the projection of commissural axons to floor plate. The FS domain is found in F-spondins, mindins, M-spondin and amphiF-spondin.

Results: We present the crystal structure of human F-spondin FS domain at 1.95Å resolution. The structure reveals a Ca2+-binding C2 domain variant with an 8-stranded antiparallel β-sandwich fold. Though the primary sequences of the FS domains of F-spondin and mindin are less than 36% identical, their overall structures are very similar. The unique feature of F-spondin FS domain is the presence of three disulfide bonds associated with the N- and C-termini of the domain and a highly conserved N-linked glycosylation site. The integrin-binding motif found in mindin is not conserved in the F-spondin FS domain.

Conclusion: The structure of the F-spondin FS domain completes the structural studies of the multiple-domain ECM molecule. The homology of its core structure to a common Ca2+- and lipid-binding C2 domain suggests that the F-spondin FS domain may be responsible for part of the membrane targeting of F-spondin in its regulation of axon development. The structural properties of the FS domain revealed in this study pave the way for further exploration into the functions of F-spondin.

Show MeSH