Sandbox Reserved 774: Difference between revisions
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<!-- PLEASE ADD YOUR CONTENT BELOW HERE --> | <!-- PLEASE ADD YOUR CONTENT BELOW HERE --> | ||
<Structure load='1QSO' size='350' frame='true' align='right' caption='3D Model of Hpa2' scene='Insert optional scene name here' /> | <Structure load='1QSO' size='350' frame='true' align='right' caption='3D Model of Hpa2, showing: chains A,B,C,D, β-sheets, main chain, side chain, and residues 100-104.' scene='Insert optional scene name here' /> | ||
=Histone Acetyltransferase Hpa2= | =Histone Acetyltransferase Hpa2= | ||
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The region around the <scene name='56/564050/Active_sites_zoom/1' target=1>active site</scene> has potential consequences for substrate binding. For Hpa2, there exists a pocket adjacent to the active site which is sealed off on two sides by the second Hpa2 monomer in each dimer. This pocket restricts the conformation of a polypeptide backbone in the vicinity of the active site. Therefore, Hpa2 is able to distinguish between potential substrate, whereby the only lysine side-chains that may enter the active site are those with surrounding polypeptides that can adopt a conformation with the ability to fit through the pocket. <ref name=Shiva/> | The region around the <scene name='56/564050/Active_sites_zoom/1' target=1>active site</scene> has potential consequences for substrate binding. For Hpa2, there exists a pocket adjacent to the active site which is sealed off on two sides by the second Hpa2 monomer in each dimer. This pocket restricts the conformation of a polypeptide backbone in the vicinity of the active site. Therefore, Hpa2 is able to distinguish between potential substrate, whereby the only lysine side-chains that may enter the active site are those with surrounding polypeptides that can adopt a conformation with the ability to fit through the pocket. <ref name=Shiva/> | ||
<Structure load='1QSM' size='350' frame='true' align='right' caption='Hpa2 + AcCoA' scene='Insert optional scene name here' /> | <Structure load='1QSM' size='350' frame='true' align='right' caption='Hpa2 + AcCoA, showing: co-factor, backbone, β-strands, active site, α-helices.' scene='Insert optional scene name here' /> | ||
=Secondary Structure= | =Secondary Structure= | ||
Most of the secondary structure elements of the monomer contribute residues involved in dimer contacts. A large part of the interface is formed by two projections from the core part of the monomer structure. The first projection is formed by the C-terminal end of strand β3, turn β3-β4, and the N-terminal end of strand β4, while the second is formed by strand β7. Together with strands β5 and β6 they form a barrel-like structure containing ten strands in which the component strands of the barrel locked together.<ref name=Shiva/> Most importantly, strand b7 from each monomer interacts between strands β5 and β6 of the opposite monomer, which also extends the central sheet structure by two strands. Also, the two projections interact with residues from helices α1 and α2, turn α1 α2, turn α2 β2, and helices α3 and α4 of the opposite monomer. There are eight β-strands, four <scene name='56/564050/Alpha_helices/2'>α-helices</scene>, and ten turns. Thirty-three percent of the secondary structure is helical (5 helices and 50 residues), while thirty-one percent consists of β-sheets (6 strands and 47 residues). <ref name=desperate/> | Most of the secondary structure elements of the monomer contribute residues involved in dimer contacts. A large part of the interface is formed by two projections from the core part of the monomer structure. The first projection is formed by the C-terminal end of strand β3, turn β3-β4, and the N-terminal end of strand β4, while the second is formed by strand β7. Together with strands β5 and β6 they form a barrel-like structure containing ten strands in which the component strands of the barrel locked together.<ref name=Shiva/> Most importantly, strand b7 from each monomer interacts between strands β5 and β6 of the opposite monomer, which also extends the central sheet structure by two strands. Also, the two projections interact with residues from helices α1 and α2, turn α1 α2, turn α2 β2, and helices α3 and α4 of the opposite monomer. There are eight <scene name='56/564050/Beta_strands/2' target=1>β-strands</scene>, four <scene name='56/564050/Alpha_helices/2'>α-helices</scene>, and ten turns. Thirty-three percent of the secondary structure is helical (5 helices and 50 residues), while thirty-one percent consists of β-sheets (6 strands and 47 residues). <ref name=desperate/> | ||
=Mechanism= | =Mechanism= | ||
