Sandbox Reserved 1493: Difference between revisions

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Its <scene name='80/802667/Beta_head/2'>head</scene> is composed of a '''β I domain''' which has a fold similar to the I domain of the head of the α subunit. Is has a <scene name='80/802667/Mg_in_beta_head_midas/2'>Mg2+</scene> coordinating '''metal ion dependent adhesion site (MIDAS)''' motif and a site adjacent to MIDAS ('''ADMIDAS''') which coordinates ions and plays a part in activity modulation. In the head can be found the RGD and KGD binding sites.

Its '''stalk''' is mainly composed of a plexin-sempahorin-integrin (PSI) domain and a '''hybrid domain'''. A '''cysteine-rich core''' occupies the extracellular part of β3 from residues 400 to 650. Other cysteins links the N-terminal of the protein to the β I domain thanks to a long-range disulfide bond. <scene name='80/802667/Beta_head_cysteines/1'>Cysteines</scene> ''(displayed in purple, disulfide bonds in yellow)'' of the extracellular domain the β subunit are thought to have a role in the activation of the headpiece.

Its '''stalk''' is mainly composed of a plexin-sempahorin-integrin (PSI) domain and a '''hybrid domain'''. A '''cysteine-rich core''' occupies the extracellular part of β3 from residues 400 to 650. Other cysteins links the N-terminal of the protein to the β I domain thanks to a long-range disulfide bond. <scene name='80/802667/Beta_head_cysteines/1'>Cysteines</scene> ''(displayed in purple, disulfide bonds in yellow)'' of the extracellular domain of the β subunit are thought to have a role in the activation of the headpiece.

The cytoplasmic tail of the β3 subunit has a NPLY domain which binds proteins with phosphotyrosine binding (PTB) domains.

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αIIbβ3 can also recognize and bind to the '''Arg-Gly-Asp (RGD) sequence'''. This pattern is present within flexible loop regions of fibrinogen α-subunit as well as in other ligands. Indeed, fibronectin binds to αIIbβ3 thanks an Arg-Gly-Asp-Ser-Pro sequence (which is located at the apex of a flexible loop between two β-strands) and von Willebrand factor thanks to the Arg-Gly-Asp sequence in the C1 domain.

RGD binding present '''similar features to binding of the γC domain''' of fibrinogen to the KQAGDV binding site: the Gly residue is in the same pocket between the two subunits, and the Asp side chain coordinates the <scene name='80/802667/Mg_in_beta_head_midas/1'>Mg2+ ion</scene> in MIDAS. Then the Asp side chain forms hydrogen bonds to amide groups including two in the β I domain. The side chain of Arg (along the same pocket as the Lys side chain of the KQAGDV motif of γC) enables to position its guanidinium group for hydrogen bonding to Asp 224.

RGD binding present '''similar features to binding of the γC domain''' of fibrinogen to the KQAGDV binding site: the Gly residue is in the same pocket between the two subunits, and the Asp side chain coordinates the <scene name='80/802667/Mg_in_beta_head_midas/2'>Mg2+ ion</scene> in MIDAS. Then the Asp side chain forms hydrogen bonds to amide groups including two in the β I domain. The side chain of Arg (along the same pocket as the Lys side chain of the KQAGDV motif of γC) enables to position its guanidinium group for hydrogen bonding to Asp 224.

Structural data revealed the HHLGGAKQAGDV peptide of the γC domain of fibrinogen binds to an extended site on the receptor that includes the RGD binding site. There is thus '''competing''' between he HHLGGAKQAGDV peptide and RGD patterns.

Sandbox Reserved 1493: Difference between revisions

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@@ Line 37: / Line 37: @@
 Its <scene name='80/802667/Beta_head/2'>head</scene> is composed of a '''β I domain''' which has a fold similar to the I domain of the head of the α subunit. Is has a <scene name='80/802667/Mg_in_beta_head_midas/2'>Mg2+</scene> coordinating '''metal ion dependent adhesion site (MIDAS)''' motif and a site adjacent to MIDAS ('''ADMIDAS''') which coordinates ions and plays a part in activity modulation. In the head can be found the RGD and KGD binding sites.
-Its '''stalk''' is mainly composed of a plexin-sempahorin-integrin (PSI) domain and a '''hybrid domain'''. A '''cysteine-rich core''' occupies the extracellular part of β3 from residues 400 to 650. Other cysteins links the N-terminal of the protein to the β I domain thanks to a long-range disulfide bond. <scene name='80/802667/Beta_head_cysteines/1'>Cysteines</scene> ''(displayed in purple, disulfide bonds in yellow)'' of the extracellular domain the β subunit are thought to have a role in the activation of the headpiece.
+Its '''stalk''' is mainly composed of a plexin-sempahorin-integrin (PSI) domain and a '''hybrid domain'''. A '''cysteine-rich core''' occupies the extracellular part of β3 from residues 400 to 650. Other cysteins links the N-terminal of the protein to the β I domain thanks to a long-range disulfide bond. <scene name='80/802667/Beta_head_cysteines/1'>Cysteines</scene> ''(displayed in purple, disulfide bonds in yellow)'' of the extracellular domain of the β subunit are thought to have a role in the activation of the headpiece.
 The cytoplasmic tail of the β3 subunit has a NPLY domain which binds proteins with phosphotyrosine binding (PTB) domains.
@@ Line 67: / Line 67: @@
 αIIbβ3 can also recognize and bind to the '''Arg-Gly-Asp (RGD) sequence'''. This pattern is present within flexible loop regions of fibrinogen α-subunit as well as in other ligands. Indeed, fibronectin binds to αIIbβ3 thanks an Arg-Gly-Asp-Ser-Pro sequence (which is located at the apex of a flexible loop between two β-strands) and von Willebrand factor thanks to the Arg-Gly-Asp sequence in the C1 domain.
-RGD binding present '''similar features to binding of the γC domain''' of fibrinogen to the KQAGDV binding site: the Gly residue is in the same pocket between the two subunits, and the Asp side chain coordinates the <scene name='80/802667/Mg_in_beta_head_midas/1'>Mg2+ ion</scene> in MIDAS. Then the Asp side chain forms hydrogen bonds to amide groups including two in the β I domain. The side chain of Arg (along the same pocket as the Lys side chain of the KQAGDV motif of γC) enables to position its guanidinium group for hydrogen bonding to Asp 224.
+RGD binding present '''similar features to binding of the γC domain''' of fibrinogen to the KQAGDV binding site: the Gly residue is in the same pocket between the two subunits, and the Asp side chain coordinates the <scene name='80/802667/Mg_in_beta_head_midas/2'>Mg2+ ion</scene> in MIDAS. Then the Asp side chain forms hydrogen bonds to amide groups including two in the β I domain. The side chain of Arg (along the same pocket as the Lys side chain of the KQAGDV motif of γC) enables to position its guanidinium group for hydrogen bonding to Asp 224.
 Structural data revealed the HHLGGAKQAGDV peptide of the γC domain of fibrinogen binds to an extended site on the receptor that includes the RGD binding site. There is thus '''competing''' between he HHLGGAKQAGDV peptide and RGD patterns.