Sandbox Reserved 1645: Difference between revisions
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3D model represents these parts of fibrillin-1: <scene name='86/868178/Cbegf9/2'>cb-EGF9</scene>, <scene name='86/868178/Tb4/2'>TGF-bp 4 containing second hybrid domain</scene> and <scene name='86/868178/Cbegf10/1'>cb-EGF10</scene>. | 3D model represents these parts of fibrillin-1: <scene name='86/868178/Cbegf9/2'>cb-EGF9</scene>, <scene name='86/868178/Tb4/2'>TGF-bp 4 containing second hybrid domain</scene> and <scene name='86/868178/Cbegf10/1'>cb-EGF10</scene>. | ||
The protein fibrillin-1 contains 59 subunits either called '''epidermal growth factor-like domain''' ([[EGF]]), or '''transforming growth factor β binding protein-like domain''' (8 [[TGF-bp]]). EGFs are repeated in tandem along with the whole protein which represents about 75% of the total Fibrillin-1 length, and they are interrupted by the insertion of the TGF-bp units, which contain 8 cysteines each (<scene name='86/868178/Disulfide_bridges_in_tgf-bp/2'>4 disulfide bridges</scene> are formed). In total, there are 47 motifs of EGF in one Fibrillin-1, but only 43 of them contain calcium-binding sequences. In consequence, these EGF are named cb-EGF for their ability to bind calcium cations. Each EGF or cb-EGF unit contains 6 residues of cysteine which form <scene name='86/868178/Disulfide_bridges/1'>3 disulfide bridges</scene> (CYS1-CYS3, CYS2-CYS4, CYS5-CYS6) stabilizing the secondary structure of the protein. Cb-EGF units contain also a <scene name='86/868178/Ca_binding_site/1'>Ca2+ binding site</scene> composed especially by amino acids which contain an atom of oxygen or groups with azote in their lateral chains (D,N,S,Q,E). These amino acids stabilize the calcium cation by interactions between positively charged cation and hetero-atoms (oxygen or azote) of the amino acid's lateral chain. Consequently, a pentagonal bipyramidal binding site is created in which one calcium cation is bound in every cb-EGF subunit of the fibrillin-1 protein. <ref>Sandra Schrenk Carola Cenzi Thomas Bertalot Maria Teresa Conconi Rosa Di Liddo, | The protein fibrillin-1 contains 59 subunits either called '''epidermal growth factor-like domain''' ([[EGF]]), or '''transforming growth factor β binding protein-like domain''' (8 [[TGF-bp]]). EGFs are repeated in tandem along with the whole protein which represents about 75% of the total Fibrillin-1 length, and they are interrupted by the insertion of the TGF-bp units, which contain 8 cysteines each (<scene name='86/868178/Disulfide_bridges_in_tgf-bp/2'>4 disulfide bridges</scene> are formed). In total, there are 47 motifs of EGF in one Fibrillin-1, but only 43 of them contain calcium-binding sequences. In consequence, these EGF are named cb-EGF for their ability to bind calcium cations. Each EGF or cb-EGF unit contains 6 residues of cysteine which form <scene name='86/868178/Disulfide_bridges/1'>3 disulfide bridges</scene> (CYS1-CYS3, CYS2-CYS4, CYS5-CYS6) stabilizing the secondary structure of the protein. Cb-EGF units contain also a <scene name='86/868178/Ca_binding_site/1'>Ca2+ binding site</scene> composed especially by amino acids which contain an atom of oxygen or groups with azote in their lateral chains (D,N,S,Q,E). These amino acids stabilize the calcium cation by interactions between positively charged cation and hetero-atoms (oxygen or azote) of the amino acid's lateral chain. Consequently, a pentagonal bipyramidal binding site is created in which one calcium cation is bound in every cb-EGF subunit of the fibrillin-1 protein. <ref>Sandra Schrenk Carola Cenzi Thomas Bertalot Maria Teresa Conconi Rosa Di Liddo, (2017), pages: 1213-1223,https://doi.org/10.3892/ijmm.2017.3343</ref> | ||
== Biological Function == | == Biological Function == | ||
