Sandbox Reserved 822: Difference between revisions
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*On the other side of the barrel three variable loops (VL 1-3) form a bowl-like structure which is lined by positively charged residues, consituting the phosphoinositide-binding site. | *On the other side of the barrel three variable loops (VL 1-3) form a bowl-like structure which is lined by positively charged residues, consituting the phosphoinositide-binding site. | ||
The PH domain of PDK1 possesses an additional extension ('bud') N-terminal to the standard PH domain fold. This bud forms two additional β strands and one α helix and is an integral part of the overall fold. The two β strands β1' and β2'extend the β1 - β4 sheet in an antiparallel fashion through the formation of β sheet hydrogen bonds between β2'and β1. The α helix packs against this newly formed six stranded β sheet forming an additional <scene name='56/568020/Hydrophobic_core/1'>hydrophobic core</scene> outside of the standard PH domain fold. The bud binds to the β1 - β4 sheet by several additional hydrophobic contacts and buries more than 30% of the surface of the standard PH domain fold. <ref> PMID: 524332 </ref> | The PH domain of PDK1 possesses an additional extension (<scene name='56/568020/Bud/1'>'bud'</scene>) N-terminal to the standard PH domain fold. This bud forms two additional β strands and one α helix and is an integral part of the overall fold. The two β strands β1' and β2'extend the β1 - β4 sheet in an antiparallel fashion through the formation of β sheet hydrogen bonds between β2'and β1. The α helix packs against this newly formed six stranded β sheet forming an additional <scene name='56/568020/Hydrophobic_core/1'>hydrophobic core</scene> outside of the standard PH domain fold. The bud binds to the β1 - β4 sheet by several additional hydrophobic contacts and buries more than 30% of the surface of the standard PH domain fold. <ref> PMID: 524332 </ref> | ||
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=== Binding site === | === Binding site === | ||
The binding site is formed by VL 1-3 which create a shallow, positively charged pocket at the open end of the β barrel. The structure was determined from a crystal grown in the presence of Ins(1,3,4,5)P<sub>4</sub>, which is the head group of PtdIns(3,4,5)P<sub>3</sub>. The phosphoinositide-binding site is lined by positively charged residues which contact the phosphates of Ins(1,3,4,5)P<sub>4</sub> by forming up to 11 hydrogen bonds. <scene name='56/568020/Arg472/1'>Arg472</scene> forms two hydrogen bonds to the phosphate in the D1 position (D1-phosphate). | The binding site is formed by VL 1-3 which create a shallow, positively charged pocket at the open end of the β barrel. The structure was determined from a crystal grown in the presence of Ins(1,3,4,5)P<sub>4</sub>, which is the head group of PtdIns(3,4,5)P<sub>3</sub>. The phosphoinositide-binding site is lined by positively charged residues which contact the phosphates of Ins(1,3,4,5)P<sub>4</sub> by forming up to 11 hydrogen bonds. <scene name='56/568020/Arg472/1'>Arg472</scene> forms two hydrogen bonds to the phosphate in the D1 position (D1-phosphate). <scene name='56/568020/Argandlys/1'>Arg474 and Lys465</scene> contact the D3-phosphate with three hydrogen bonds in total (two for Arg474, one for Lys465) | ||
== References == | == References == | ||
<references/> | <references/> | ||