Sandbox Reserved 963

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V<sub>H</sub>(Pro40 to Lys43) corresponds to a loop in the sequence between CDRs (Complementarity Determining Regions) heavy-chain 1 (H1) and H2, located in the hinge region of the Fab away from the ligand binding site. However, this loop is associated with poor electron density and, therefore, there is some uncertainty about the accuracy of the model in this region.
V<sub>H</sub>(Pro40 to Lys43) corresponds to a loop in the sequence between CDRs (Complementarity Determining Regions) heavy-chain 1 (H1) and H2, located in the hinge region of the Fab away from the ligand binding site. However, this loop is associated with poor electron density and, therefore, there is some uncertainty about the accuracy of the model in this region.
Ser62H is a non-CDR loop involved in symmetry-related close contacts.
Ser62H is a non-CDR loop involved in symmetry-related close contacts.
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Val51 of the light chain is the only residue to fall outside allowed regions of the Ramachandran plot. The unfavorable phi/psi torsion angles arise from the fact that this residue is in a γ-turn restrained by the (i to i+2) hydrogen bond between the Gln50L backbone carbonyl and the Ser52L amide.<ref>Amyloid-beta-anti-amyloid-beta complex structure reveals an extended conformation in the immunodominant B-cell epitope.,Miles LA, Wun KS, Crespi GA, Fodero-Tavoletti MT, Galatis D, Bagley CJ, Beyreuther K, Masters CL, Cappai R, McKinstry WJ, Barnham KJ, Parker MW J Mol Biol. 2008 Mar 14;377(1):181-92. Epub 2008 Jan 30. PMID:18237744</ref>
Val51 of the light chain is the only residue to fall outside allowed regions of the Ramachandran plot. The unfavorable phi/psi torsion angles arise from the fact that this residue is in a γ-turn restrained by the (i to i+2) hydrogen bond between the Gln50L backbone carbonyl and the Ser52L amide.<ref>Amyloid-beta-anti-amyloid-beta complex structure reveals an extended conformation in the immunodominant B-cell epitope.,Miles LA, Wun KS, Crespi GA, Fodero-Tavoletti MT, Galatis D, Bagley CJ, Beyreuther K, Masters CL, Cappai R, McKinstry WJ, Barnham KJ, Parker MW J Mol Biol. 2008 Mar 14;377(1):181-92. Epub 2008 Jan 30. PMID:18237744</ref>
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Here are the <scene name='60/604482/My_first_scene/1'>alpha carbon and β sheets</scene> on the complexe.
Here are the <scene name='60/604482/My_first_scene/1'>alpha carbon and β sheets</scene> on the complexe.
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==Interactions with the ligand Aβ(1-16)==
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==Interactions with the ligand Aβ<sub>1-16</sub>==
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===Overview of the WO2:Aβ(1-16) complex===
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===Overview of the WO2:Aβ<sub>1-16</sub> complex===
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(1-16) represents the minimal zinc binding domain and contains the entire immunodominant B-cell epitope of Aβ, it is therefore interesting to see how this fragment of Aβ interacts with WO2.
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<sub>1-16</sub> represents the minimal zinc binding domain and contains the entire immunodominant B-cell epitope of Aβ, it is therefore interesting to see how this fragment of Aβ interacts with WO2.
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First, the main residues which closely contact the CDRs of WO2 by sitting within the antigen binding site of WO2 are Ala2 to Ser8 and they stretch 20 Å from the N-terminus to the C-terminus '''(Figure 2)'''.[[Image:Fig. 2.png|left|frame|'''Figure 2 :''' Surface representation of the WO2 antibody CDRs in complex with Aβ(1-16)<ref>Amyloid-beta-anti-amyloid-beta complex structure reveals an extended conformation in the immunodominant B-cell epitope.,Miles LA, Wun KS, Crespi GA, Fodero-Tavoletti MT, Galatis D, Bagley CJ, Beyreuther K, Masters CL, Cappai R, McKinstry WJ, Barnham KJ, Parker MW J Mol Biol. 2008 Mar 14;377(1):181-92. Epub 2008 Jan 30. PMID:18237744</ref>]]
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First, the main residues which closely contact the CDRs of WO2 by sitting within the antigen binding site of WO2 are Ala2 to Ser8 and they stretch 20 Å from the N-terminus to the C-terminus '''(Figure 2)'''.[[Image:Fig. 2.png|left|frame|'''Figure 2 :''' Surface representation of the WO2 antibody CDRs in complex with Aβ<sub>1-16</sub><ref>Amyloid-beta-anti-amyloid-beta complex structure reveals an extended conformation in the immunodominant B-cell epitope.,Miles LA, Wun KS, Crespi GA, Fodero-Tavoletti MT, Galatis D, Bagley CJ, Beyreuther K, Masters CL, Cappai R, McKinstry WJ, Barnham KJ, Parker MW J Mol Biol. 2008 Mar 14;377(1):181-92. Epub 2008 Jan 30. PMID:18237744</ref>]]
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The surface area of the Aβ(2-8) structure is 1118 Ų, of which 60% is buried (665 Ų) in the antibody interface. What’s more, we note two significant interfaces between Aβ and WO2 : a 367 Ų surface contacting the heavy chain and a 298 Ų surface contacting the light chain. We notice '''(Table 1)''' that residues in the middle of the Aβ(1-16) structure exhibit lower B-factors than atoms at the N- and C- termini of the Aβ(1-16) peptide, indicating they are more flexible (since the B-factor, also called the temperature factor, represents the relative vibrational motion of different parts of a structure and thus, atoms with low B-factors belong to a part of the structure quite rigid whereas atoms with high B-factors generally belong to part of a structure that is very flexible[http://en.wikipedia.org/wiki/Debye%E2%80%93Waller_factor]).[[Image:Table 2.png|frame|center|'''Table 1 :''' Buried Surface Areas (BSAs) and B-factors of Aβ residues contacting WO2<ref>Amyloid-beta-anti-amyloid-beta complex structure reveals an extended conformation in the immunodominant B-cell epitope.,Miles LA, Wun KS, Crespi GA, Fodero-Tavoletti MT, Galatis D, Bagley CJ, Beyreuther K, Masters CL, Cappai R, McKinstry WJ, Barnham KJ, Parker MW J Mol Biol. 2008 Mar 14;377(1):181-92. Epub 2008 Jan 30. PMID:18237744</ref>]] Phe4 and His6 are completely buried in the Fab interface, each with about half of its surface area buried in the V<sub>H</sub> interface and about half buried in the V<sub>L</sub> interface. All other residues are located exclusively at the interface with either the V<sub>H</sub> or the V<sub>L</sub> domains.
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The surface area of the Aβ<sub>2-8</sub> structure is 1118 Ų, of which 60% is buried (665 Ų) in the antibody interface. What’s more, we note two significant interfaces between Aβ and WO2 : a 367 Ų surface contacting the heavy chain and a 298 Ų surface contacting the light chain. We notice '''(Table 1)''' that residues in the middle of the Aβ<sub>1-16</sub> structure exhibit lower B-factors than atoms at the N- and C- termini of the Aβ<sub>1-16</sub> peptide, indicating they are more flexible (since the B-factor, also called the temperature factor, represents the relative vibrational motion of different parts of a structure and thus, atoms with low B-factors belong to a part of the structure quite rigid whereas atoms with high B-factors generally belong to part of a structure that is very flexible[http://en.wikipedia.org/wiki/Debye%E2%80%93Waller_factor]).[[Image:Table 2.png|frame|center|'''Table 1 :''' Buried Surface Areas (BSAs) and B-factors of Aβ residues contacting WO2<ref>Amyloid-beta-anti-amyloid-beta complex structure reveals an extended conformation in the immunodominant B-cell epitope.,Miles LA, Wun KS, Crespi GA, Fodero-Tavoletti MT, Galatis D, Bagley CJ, Beyreuther K, Masters CL, Cappai R, McKinstry WJ, Barnham KJ, Parker MW J Mol Biol. 2008 Mar 14;377(1):181-92. Epub 2008 Jan 30. PMID:18237744</ref>]] Phe4 and His6 are completely buried in the Fab interface, each with about half of its surface area buried in the V<sub>H</sub> interface and about half buried in the V<sub>L</sub> interface. All other residues are located exclusively at the interface with either the V<sub>H</sub> or the V<sub>L</sub> domains.
Residues of the light chain closely contacting Aβ residues include His27(D)L, Ser27(E)L and Tyr32L from light-chain CDR 1 (L1) and Ser92L, Leu93L, Val94L and Leu96L from L3.
Residues of the light chain closely contacting Aβ residues include His27(D)L, Ser27(E)L and Tyr32L from light-chain CDR 1 (L1) and Ser92L, Leu93L, Val94L and Leu96L from L3.
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===Details of the close interactions between WO2 and Aβ(2-8)===
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===Details of the close interactions between WO2 and Aβ<sub>2-8</sub>===
As mentionned previously, the residues of Aβ closely interacting with the CDRs of WO2 extend from Ala2 to Ser8. Let's focus on the interactions of each of these residues with the antibody '''(Figure 3)''':
As mentionned previously, the residues of Aβ closely interacting with the CDRs of WO2 extend from Ala2 to Ser8. Let's focus on the interactions of each of these residues with the antibody '''(Figure 3)''':
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[[Image:Fig. 3.png|frame|right|'''Figure 3 :''' Schematic drawing produced using the programme LIGPLOT, displaying WO2 residues interacting with Aβ(1-16)<ref>Amyloid-beta-anti-amyloid-beta complex structure reveals an extended conformation in the immunodominant B-cell epitope.,Miles LA, Wun KS, Crespi GA, Fodero-Tavoletti MT, Galatis D, Bagley CJ, Beyreuther K, Masters CL, Cappai R, McKinstry WJ, Barnham KJ, Parker MW J Mol Biol. 2008 Mar 14;377(1):181-92. Epub 2008 Jan 30. PMID:18237744</ref>]]
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[[Image:Fig. 3.png|frame|right|'''Figure 3 :''' Schematic drawing produced using the programme LIGPLOT, displaying WO2 residues interacting with Aβ<sub>1-16</sub><ref>Amyloid-beta-anti-amyloid-beta complex structure reveals an extended conformation in the immunodominant B-cell epitope.,Miles LA, Wun KS, Crespi GA, Fodero-Tavoletti MT, Galatis D, Bagley CJ, Beyreuther K, Masters CL, Cappai R, McKinstry WJ, Barnham KJ, Parker MW J Mol Biol. 2008 Mar 14;377(1):181-92. Epub 2008 Jan 30. PMID:18237744</ref>]]
====Interactions with Ala2====
====Interactions with Ala2====
Ala2 of is recognized by WO2 through a hydrogen bond between its main chain carbonyl and the amide of Val94L.
Ala2 of is recognized by WO2 through a hydrogen bond between its main chain carbonyl and the amide of Val94L.
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Unliganted and liganted structures '''(Figure 4)''' superimpose very closely with an r.m.s.d. (root-mean-square deviation) of 0.3 Å on all Cα atoms (the r.m.s.d. is the measure of the average distance between the atoms of superimposed proteins[http://en.wikipedia.org/wiki/Root-mean-square_deviation]). Even the CDRs of liganted and unliganted states are barely distinguishable. Except some small variations (<1 Å) around Ser27(E)L (L1), Lys33H (H1), Asp54H (H2) and Glu100(C)H (H3), there is no substantial change in the CDRs when Aβ binds WO2.
Unliganted and liganted structures '''(Figure 4)''' superimpose very closely with an r.m.s.d. (root-mean-square deviation) of 0.3 Å on all Cα atoms (the r.m.s.d. is the measure of the average distance between the atoms of superimposed proteins[http://en.wikipedia.org/wiki/Root-mean-square_deviation]). Even the CDRs of liganted and unliganted states are barely distinguishable. Except some small variations (<1 Å) around Ser27(E)L (L1), Lys33H (H1), Asp54H (H2) and Glu100(C)H (H3), there is no substantial change in the CDRs when Aβ binds WO2.
Moreover, thanks to temperature-factors analysis, it appears that CDR H1 is much less flexible in the liganted structure.<ref>Amyloid-beta-anti-amyloid-beta complex structure reveals an extended conformation in the immunodominant B-cell epitope.,Miles LA, Wun KS, Crespi GA, Fodero-Tavoletti MT, Galatis D, Bagley CJ, Beyreuther K, Masters CL, Cappai R, McKinstry WJ, Barnham KJ, Parker MW J Mol Biol. 2008 Mar 14;377(1):181-92. Epub 2008 Jan 30. PMID:18237744</ref>
Moreover, thanks to temperature-factors analysis, it appears that CDR H1 is much less flexible in the liganted structure.<ref>Amyloid-beta-anti-amyloid-beta complex structure reveals an extended conformation in the immunodominant B-cell epitope.,Miles LA, Wun KS, Crespi GA, Fodero-Tavoletti MT, Galatis D, Bagley CJ, Beyreuther K, Masters CL, Cappai R, McKinstry WJ, Barnham KJ, Parker MW J Mol Biol. 2008 Mar 14;377(1):181-92. Epub 2008 Jan 30. PMID:18237744</ref>
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[[Image:Fig. 1b.png|frame|'''Figure 4 :''' Representation of Aβ (shown as ball-and-stick) in the WO2 Fab variable domain CDRs after superimposition of their Cα atoms. The unliganted Form A is in yellow and the complex with Aβ(1-16) is in blue<ref>Amyloid-beta-anti-amyloid-beta complex structure reveals an extended conformation in the immunodominant B-cell epitope.,Miles LA, Wun KS, Crespi GA, Fodero-Tavoletti MT, Galatis D, Bagley CJ, Beyreuther K, Masters CL, Cappai R, McKinstry WJ, Barnham KJ, Parker MW J Mol Biol. 2008 Mar 14;377(1):181-92. Epub 2008 Jan 30. PMID:18237744</ref>]]
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[[Image:Fig. 1b.png|frame|'''Figure 4 :''' Representation of Aβ (shown as ball-and-stick) in the WO2 Fab variable domain CDRs after superimposition of their Cα atoms. The unliganted Form A is in yellow and the complex with Aβ<sub>1-16</sub> is in blue<ref>Amyloid-beta-anti-amyloid-beta complex structure reveals an extended conformation in the immunodominant B-cell epitope.,Miles LA, Wun KS, Crespi GA, Fodero-Tavoletti MT, Galatis D, Bagley CJ, Beyreuther K, Masters CL, Cappai R, McKinstry WJ, Barnham KJ, Parker MW J Mol Biol. 2008 Mar 14;377(1):181-92. Epub 2008 Jan 30. PMID:18237744</ref>]]
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*PFA1, PFA2
*PFA1, PFA2
*[[3bkc]] : WO2 Fab Form B
*[[3bkc]] : WO2 Fab Form B
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*[[3bkj]] : WO2 Fab:Aβ(1-16) complex
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*[[3bkj]] : WO2 Fab:Aβ<sub>1-16</sub> complex
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*[[3bae]] : WO2 Fab:Aβ(1-28) complex
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*[[3bae]] : WO2 Fab:Aβ<sub>1-28</sub> complex
==Contributors==
==Contributors==

Revision as of 21:15, 3 January 2015

Anti-amyloid-beta Fab WO2 (Form A, P212121)

3bkm, resolution 1.60Å

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