Sandbox Reserved 766: Difference between revisions

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[[Image:Screen Shot 2013-12-03 at 10.22.56 PM.png |420px|Figure.... Proposed reaction mechanism for ASNS using Aspartic Acid, Glutamine and ATP to synthesize Asparagine and Glutamic Acid.]]

'''Asparagine Synthetase''' catalyzes the interconversion of Aspartic Acid and Glutamine to Asparagine and Glutamic Acid. This is not a straight forward transferase reaction since the interconversion is not directly between Aspartic Acid and Glutamine. Instead this reaction more closely resembles a two part ATP dependent ligase reaction. ASNS has two distinct pockets; one where Adenosine Triphosphate (ATP) binds and is stabilized by the hydrogen bonds it forms with '''Ser 346''' (Gamma Oxygen) and amide groups of '''Val 272''', '''Leu 232''' and '''Gly 347'''. This binding of ATP to the N-Terminal domain is to stabilize the intermediate it forms with the Aspartic Acid; Beta-Aspartyl AMP (BAspAMP). This intermediate complex has to bind to the ASNS enzyme before the Glutamine binds into its pocket to establish coordination of the binding sites within the ASNS enzyme. After the BAspAMP intermediate binds in its pocket and establishes the coordination of the enzyme the Glutamine binds to its pocket in the C-Terminal domain and is stabilized specifically by its bonds with '''Arg 49''', '''Asn 74''', '''Glu 76''', and '''Asp 98''' residues.~~<ref>"RCSB Protein Data Bank - RCSB PDB - 1CT9 Structure Summary." RCSB Protein Data Bank - RCSB PDB - 1CT9 Structure Summary. N.p., n.d. Web. 01 Dec. 2013.<ref/>~~ Once the substrates have been bound and stabilized free water hydrolyzes the amine group on the side chain of Glutamine causing the newly formed ammonia (NH3) group to detach leaving a carboxylate ion as the new functional group converting the Glutamine to Glutamate. The free Ammonia molecule then binds with the carbonyl carbon of the BAspAMP complex forcing the carbonyl carbon of the Aspartic Acid residue to favor the amine group both electrochemically and sterically and break its bond with the AMP releasing it, inorganic phosphate and forming a free Asparagine molecule, excess water in the environment then protonates the Glutamate into a free form Glutamic Acid molecule. This can be seen in the above right figure. The main difference between ASNS-B and ASNS-A is that instead of using Glutamine for the Nitrogen source for this reaction ASNS-A uses ammonia or diatomic Nitrogen directly.

'''Asparagine Synthetase''' catalyzes the interconversion of Aspartic Acid and Glutamine to Asparagine and Glutamic Acid. This is not a straight forward transferase reaction since the interconversion is not directly between Aspartic Acid and Glutamine. Instead this reaction more closely resembles a two part ATP dependent ligase reaction. ASNS has two distinct pockets; one where Adenosine Triphosphate (ATP) binds and is stabilized by the hydrogen bonds it forms with '''Ser 346''' (Gamma Oxygen) and amide groups of '''Val 272''', '''Leu 232''' and '''Gly 347'''. This binding of ATP to the N-Terminal domain is to stabilize the intermediate it forms with the Aspartic Acid; Beta-Aspartyl AMP (BAspAMP). This intermediate complex has to bind to the ASNS enzyme before the Glutamine binds into its pocket to establish coordination of the binding sites within the ASNS enzyme. After the BAspAMP intermediate binds in its pocket and establishes the coordination of the enzyme the Glutamine binds to its pocket in the C-Terminal domain and is stabilized specifically by its bonds with '''Arg 49''', '''Asn 74''', '''Glu 76''', and '''Asp 98''' residues. Once the substrates have been bound and stabilized free water hydrolyzes the amine group on the side chain of Glutamine causing the newly formed ammonia (NH3) group to detach leaving a carboxylate ion as the new functional group converting the Glutamine to Glutamate. The free Ammonia molecule then binds with the carbonyl carbon of the BAspAMP complex forcing the carbonyl carbon of the Aspartic Acid residue to favor the amine group both electrochemically and sterically and break its bond with the AMP releasing it, inorganic phosphate and forming a free Asparagine molecule, excess water in the environment then protonates the Glutamate into a free form Glutamic Acid molecule. This can be seen in the above right figure. The main difference between ASNS-B and ASNS-A is that instead of using Glutamine for the Nitrogen source for this reaction ASNS-A uses ammonia or diatomic Nitrogen directly.

==Future Research and Prospective Applications For Asparagine Synthetase==

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===Ovarian Cancer Predictive Bio-Marker===

Recent studies have been trying to find a potential link between the amount of ASNS activity in certain cell cultures as a precursor for L-Asparaginase activity. L-Asparaginase is an enzyme that degrades Asparagine and has been used since the 1970's in basic cancer treatment plans for acute lymphoblastic leukemia (site MCT). The body will naturally secrete L-Asparaginase as a response to a potential forming tumor or potential cancer cell aggregation. These studies are finding a correlation between the amount of ASNS being expressed prior to the expression of L-Asparaginase synthetase,<ref>"Asparagine Synthetase as a Causal, Predictive Biomarker for L-asparaginase Activity in Ovarian Cancer Cells." Asparagine Synthetase as a Causal, Predictive Biomarker for L-asparaginase Activity in Ovarian Cancer Cells. N.p., n.d. Web. 02 Dec. 2013.<ref/> since L-Asparaginase has only been shown to help combat lymphoblastic leukemia this would not be a direct treatment but rather an indicator that something is happening that requires attention and hopefully allow doctors to screen for ASNS activity and catch ovarian cancer in it's earlier stages when it is more treatable and easier to remove from the body.

Recent studies have been trying to find a potential link between the amount of ASNS activity in certain cell cultures as a precursor for L-Asparaginase activity. L-Asparaginase is an enzyme that degrades Asparagine and has been used since the 1970's in basic cancer treatment plans for acute lymphoblastic leukemia (site MCT). The body will naturally secrete L-Asparaginase as a response to a potential forming tumor or potential cancer cell aggregation. These studies are finding a correlation between the amount of ASNS being expressed prior to the expression of L-Asparaginase synthetase, since L-Asparaginase has only been shown to help combat lymphoblastic leukemia this would not be a direct treatment but rather an indicator that something is happening that requires attention and hopefully allow doctors to screen for ASNS activity and catch ovarian cancer in it's earlier stages when it is more treatable and easier to remove from the body.

==References==

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@@ Line 24: / Line 24: @@
 [[Image:Screen Shot 2013-12-03 at 10.22.56 PM.png |420px|Figure.... Proposed reaction mechanism for ASNS using Aspartic Acid, Glutamine and ATP to synthesize Asparagine and Glutamic Acid.]]
-'''Asparagine Synthetase''' catalyzes the interconversion of Aspartic Acid and Glutamine to Asparagine and Glutamic Acid. This is not a straight forward transferase reaction since the interconversion is not directly between Aspartic Acid and Glutamine. Instead this reaction more closely resembles a two part ATP dependent ligase reaction. ASNS has two distinct pockets; one where Adenosine Triphosphate (ATP) binds and is stabilized by the hydrogen bonds it forms with '''Ser 346''' (Gamma Oxygen) and amide groups of '''Val 272''', '''Leu 232''' and '''Gly 347'''. This binding of ATP to the N-Terminal domain is to stabilize the intermediate it forms with the Aspartic Acid; Beta-Aspartyl AMP (BAspAMP). This intermediate complex has to bind to the ASNS enzyme before the Glutamine binds into its pocket to establish coordination of the binding sites within the ASNS enzyme. After the BAspAMP intermediate binds in its pocket and establishes the coordination of the enzyme the Glutamine binds to its pocket in the C-Terminal domain and is stabilized specifically by its bonds with '''Arg 49''', '''Asn 74''', '''Glu 76''', and '''Asp 98''' residues.<ref>"RCSB Protein Data Bank - RCSB PDB - 1CT9 Structure Summary." RCSB Protein Data Bank - RCSB PDB - 1CT9 Structure Summary. N.p., n.d. Web. 01 Dec. 2013.<ref/> Once the substrates have been bound and stabilized free water hydrolyzes the amine group on the side chain of Glutamine causing the newly formed ammonia (NH3) group to detach leaving a carboxylate ion as the new functional group converting the Glutamine to Glutamate. The free Ammonia molecule then binds with the carbonyl carbon of the BAspAMP complex forcing the carbonyl carbon of the Aspartic Acid residue to favor the amine group both electrochemically and sterically and break its bond with the AMP releasing it, inorganic phosphate and forming a free Asparagine molecule, excess water in the environment then protonates the Glutamate into a free form Glutamic Acid molecule. This can be seen in the above right figure. The main difference between ASNS-B and ASNS-A is that instead of using Glutamine for the Nitrogen source for this reaction ASNS-A uses ammonia or diatomic Nitrogen directly.
+'''Asparagine Synthetase''' catalyzes the interconversion of Aspartic Acid and Glutamine to Asparagine and Glutamic Acid. This is not a straight forward transferase reaction since the interconversion is not directly between Aspartic Acid and Glutamine. Instead this reaction more closely resembles a two part ATP dependent ligase reaction. ASNS has two distinct pockets; one where Adenosine Triphosphate (ATP) binds and is stabilized by the hydrogen bonds it forms with '''Ser 346''' (Gamma Oxygen) and amide groups of '''Val 272''', '''Leu 232''' and '''Gly 347'''. This binding of ATP to the N-Terminal domain is to stabilize the intermediate it forms with the Aspartic Acid; Beta-Aspartyl AMP (BAspAMP). This intermediate complex has to bind to the ASNS enzyme before the Glutamine binds into its pocket to establish coordination of the binding sites within the ASNS enzyme. After the BAspAMP intermediate binds in its pocket and establishes the coordination of the enzyme the Glutamine binds to its pocket in the C-Terminal domain and is stabilized specifically by its bonds with '''Arg 49''', '''Asn 74''', '''Glu 76''', and '''Asp 98''' residues. Once the substrates have been bound and stabilized free water hydrolyzes the amine group on the side chain of Glutamine causing the newly formed ammonia (NH3) group to detach leaving a carboxylate ion as the new functional group converting the Glutamine to Glutamate. The free Ammonia molecule then binds with the carbonyl carbon of the BAspAMP complex forcing the carbonyl carbon of the Aspartic Acid residue to favor the amine group both electrochemically and sterically and break its bond with the AMP releasing it, inorganic phosphate and forming a free Asparagine molecule, excess water in the environment then protonates the Glutamate into a free form Glutamic Acid molecule. This can be seen in the above right figure. The main difference between ASNS-B and ASNS-A is that instead of using Glutamine for the Nitrogen source for this reaction ASNS-A uses ammonia or diatomic Nitrogen directly.
 ==Future Research and Prospective Applications For Asparagine Synthetase==
@@ Line 33: / Line 33: @@
 ===Ovarian Cancer Predictive Bio-Marker===
-Recent studies have been trying to find a potential link between the amount of ASNS activity in certain cell cultures as a precursor for L-Asparaginase activity. L-Asparaginase is an enzyme that degrades Asparagine and has been used since the 1970's in basic cancer treatment plans for acute lymphoblastic leukemia (site MCT). The body will naturally secrete L-Asparaginase as a response to a potential forming tumor or potential cancer cell aggregation. These studies are finding a correlation between the amount of ASNS being expressed prior to the expression of L-Asparaginase synthetase,<ref>"Asparagine Synthetase as a Causal, Predictive Biomarker for L-asparaginase Activity in Ovarian Cancer Cells." Asparagine Synthetase as a Causal, Predictive Biomarker for L-asparaginase Activity in Ovarian Cancer Cells. N.p., n.d. Web. 02 Dec. 2013.<ref/> since L-Asparaginase has only been shown to help combat lymphoblastic leukemia this would not be a direct treatment but rather an indicator that something is happening that requires attention and hopefully allow doctors to screen for ASNS activity and catch ovarian cancer in it's earlier stages when it is more treatable and easier to remove from the body.
+Recent studies have been trying to find a potential link between the amount of ASNS activity in certain cell cultures as a precursor for L-Asparaginase activity. L-Asparaginase is an enzyme that degrades Asparagine and has been used since the 1970's in basic cancer treatment plans for acute lymphoblastic leukemia (site MCT). The body will naturally secrete L-Asparaginase as a response to a potential forming tumor or potential cancer cell aggregation. These studies are finding a correlation between the amount of ASNS being expressed prior to the expression of L-Asparaginase synthetase, since L-Asparaginase has only been shown to help combat lymphoblastic leukemia this would not be a direct treatment but rather an indicator that something is happening that requires attention and hopefully allow doctors to screen for ASNS activity and catch ovarian cancer in it's earlier stages when it is more treatable and easier to remove from the body.
 ==References==