Sandbox Reserved 702: Difference between revisions

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[[Adenylyl cyclase]] activity of the edema factor requires two magnesium ions. One of them is coordinated by <scene name='Sandbox_Reserved_702/Asp_and_his/1'>two aspartic residues (D491 and D493) and the histidine 577.</scene> The other one is coordinated by the non-esterified oxygens of α, β and γ phosphates of ATP and by aspartic D493. The distance between these two magnesium ions is about 4.5 Å. One ion deprotonates the 3'OH of ATP whereas the other one stabilizes the penta-covalent intermediate during the transition state. <ref> PMID: 15719022</ref>

[[Adenylyl cyclase]] activity of the edema factor requires two magnesium ions. One of them is coordinated by <scene name='Sandbox_Reserved_702/Asp_and_his/2'>two aspartic residues (D491 and D493) and the histidine 577.</scene> The other one is coordinated by the non-esterified oxygens of α, β and γ phosphates of ATP and by aspartic D493. The distance between these two magnesium ions is about 4.5 Å. One ion deprotonates the 3'OH of ATP whereas the other one stabilizes the penta-covalent intermediate during the transition state. <ref> PMID: 15719022</ref>

<scene name='Sandbox_Reserved_702/Histidine_351/1'>Histidine 351</scene> also plays a key role in the [[adenylyl cyclase]] reaction. Histidine is a crucial amino acid because its pKa (6.8) is close to pH of cytoplasm. It may intervene in proton-transfer reactions. Histidine 351 has a critical role in the catalytic activity of edema factor but is not a catalytic base. Since it is about 6.0 Å away from the 3'O of cAMP, its role is to allow a water molecule to enter between them. Histidine does not act as a general base (acceptor of 3'OH proton), but is facilitates an increase in the concentration of HO- ions in the proximity of the 3'OH group. <ref> PMID: 15719022</ref>

Sandbox Reserved 702: Difference between revisions

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Revision as of 16:40, 6 January 2013 view source Charlotte Kern (talk \| contribs) 157 edits →Two magnesium ions are coordinated by the catalytic site ← Older edit		Revision as of 16:45, 6 January 2013 view source Charlotte Kern (talk \| contribs) 157 edits →Two magnesium ions are coordinated by the catalytic site Newer edit →
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	[[Adenylyl cyclase]] activity of the edema factor requires two magnesium ions. One of them is coordinated by <scene name='Sandbox_Reserved_702/Asp_and_his/1'>two aspartic residues (D491 and D493) and the histidine 577.</scene> The other one is coordinated by the non-esterified oxygens of α, β and γ phosphates of ATP and by aspartic D493. The distance between these two magnesium ions is about 4.5 Å. One ion deprotonates the 3'OH of ATP whereas the other one stabilizes the penta-covalent intermediate during the transition state. <ref> PMID: 15719022</ref>		[[Adenylyl cyclase]] activity of the edema factor requires two magnesium ions. One of them is coordinated by <scene name='Sandbox_Reserved_702/Asp_and_his/2'>two aspartic residues (D491 and D493) and the histidine 577.</scene> The other one is coordinated by the non-esterified oxygens of α, β and γ phosphates of ATP and by aspartic D493. The distance between these two magnesium ions is about 4.5 Å. One ion deprotonates the 3'OH of ATP whereas the other one stabilizes the penta-covalent intermediate during the transition state. <ref> PMID: 15719022</ref>

	<scene name='Sandbox_Reserved_702/Histidine_351/1'>Histidine 351</scene> also plays a key role in the [[adenylyl cyclase]] reaction. Histidine is a crucial amino acid because its pKa (6.8) is close to pH of cytoplasm. It may intervene in proton-transfer reactions. Histidine 351 has a critical role in the catalytic activity of edema factor but is not a catalytic base. Since it is about 6.0 Å away from the 3'O of cAMP, its role is to allow a water molecule to enter between them. Histidine does not act as a general base (acceptor of 3'OH proton), but is facilitates an increase in the concentration of HO- ions in the proximity of the 3'OH group. <ref> PMID: 15719022</ref>		<scene name='Sandbox_Reserved_702/Histidine_351/1'>Histidine 351</scene> also plays a key role in the [[adenylyl cyclase]] reaction. Histidine is a crucial amino acid because its pKa (6.8) is close to pH of cytoplasm. It may intervene in proton-transfer reactions. Histidine 351 has a critical role in the catalytic activity of edema factor but is not a catalytic base. Since it is about 6.0 Å away from the 3'O of cAMP, its role is to allow a water molecule to enter between them. Histidine does not act as a general base (acceptor of 3'OH proton), but is facilitates an increase in the concentration of HO- ions in the proximity of the 3'OH group. <ref> PMID: 15719022</ref>