User:Youngsen Jeng: Difference between revisions

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== Outline of the project ==

== Outline of the project(revised) ==

Glutamine ~~Synthetase found~~ in ~~human enzyme~~, ~~classed as Glutamine Synthetase II, is made up~~ of ~~ten~~ identical subunits ~~<'''Insert wiki here'''>~~.

Glutamine synthetase(GS) is an enzyme that plays an essential role in the metabolism of nitrogen by catalyzing the condensation of glutamate and ammonia to form glutamine. Class I enzymes (GSI) are specific to prokaryotes, and are oligomers of 12 identical subunits. The activity of Glutamine Synthetase I-type enzyme is controlled by the adenylation of a tyrosine residue<'''Insert wiki here'''>.

Glutamine Synthetase is a ~~trimetallic enzyme containing two divalent cation sites (n1,n2)~~ <'''Insert wiki here'''> ~~and one~~ monovalent cation ~~site per subunit<Insert wiki here>. Structural stabilization of Glutamine Synthetase by divalent cations, especially by the n1 ion, has been ascribed~~ to the ~~attraction~~ of ~~the positive charges to the negative charges of glutamate~~ and ~~ATP and of their ligands~~. ~~<'''Insert wiki here'''>~~

~~The quaternary structure of~~ Glutamine Synthetase is ~~found to be~~ stabilized by ~~monovalent cations. (Ginsburg & Stadtman, 1973). The metal ions~~ Mn2+ and Mg2+ ~~are required for the activity and for the structural stability of Glutamine Synthetase.~~ <'''Insert wiki here'''>. Interactions of the positively charged monovalent cation with the negatively charged substrate glutamate, Glu 212, Ser 53’, and Asp 50’ could strengthen the active conformation. <Insert wiki here> Because Ser 53’and Asp 50’reside at the subunit contact surface, the monovalent cation enhances the “side-to-side” intersubunit interaction. <'''Insert wiki here'''>

The positively charged monovalent cation contributes to the structural stability of GS. Ginsburg and Stadtman(1973) concluded that dodecameric E. coli Glutamine Synthetase is stabilized by Mn2+ and Mg2+<'''Insert wiki here'''>, and that monovalent cations stabilize of the quaternary structure of GS. Stabilization by the monovalent cation may be due both to the electrostatic effects of its positive charge and to other components of the energy of the metal-protein bonding. Interactions of the positively charged monovalent cation with the negatively charged substrate glutamate, Glu 212, Ser 53’, and Asp 50’ could strengthen the active conformation<'''Insert wiki here'''>. Because Ser 53’and Asp 50’reside at the subunit contact surface, the monovalent cation enhances the “side to side” intersubunit interaction.

Structural stabilization of Glutamine Synthetase by divalent cations, especially by the n1 ion<'''Insert wiki here'''>, has been ascribed to the attraction of their positive charges to the negative charges of glutamate and ATP and of their ligands<'''Insert wiki here'''> (Liaw et al., 1993~).

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@@ Line 29: / Line 29: @@
-== Outline of the project ==
+== Outline of the project(revised) ==
-Glutamine Synthetase found in human enzyme, classed as Glutamine Synthetase II, is made up of ten identical subunits <'''Insert wiki here'''>.
+Glutamine synthetase(GS) is an enzyme that plays an essential role in the metabolism of nitrogen by catalyzing the condensation of glutamate and ammonia to form glutamine. Class I enzymes (GSI) are specific to prokaryotes, and are oligomers of 12 identical subunits. The activity of Glutamine Synthetase I-type enzyme is controlled by the adenylation of a tyrosine residue<'''Insert wiki here'''>.
-Glutamine Synthetase is a trimetallic enzyme containing two divalent cation sites (n1,n2) <'''Insert wiki here'''> and one monovalent cation site per subunit<Insert wiki here>. Structural stabilization of Glutamine Synthetase by divalent cations, especially by the n1 ion, has been ascribed to the attraction of the positive charges to the negative charges of glutamate and ATP and of their ligands. <'''Insert wiki here'''>
-The quaternary structure of Glutamine Synthetase is found to be stabilized by monovalent cations. (Ginsburg & Stadtman, 1973). The metal ions Mn2+ and Mg2+ are required for the activity and for the structural stability of Glutamine Synthetase. <'''Insert wiki here'''>. Interactions of the positively charged monovalent cation with the negatively charged substrate glutamate, Glu 212, Ser 53’, and Asp 50’ could strengthen the active conformation. <Insert wiki here> Because Ser 53’and Asp 50’reside at the subunit contact surface, the monovalent cation enhances the “side-to-side” intersubunit interaction. <'''Insert wiki here'''>
+The positively charged monovalent cation contributes to the structural stability of GS. Ginsburg and Stadtman(1973) concluded that dodecameric E. coli Glutamine Synthetase is stabilized by Mn2+ and Mg2+<'''Insert wiki here'''>, and that monovalent cations stabilize of the quaternary structure of GS. Stabilization by the monovalent cation may be due both to the electrostatic effects of its positive charge and to other components of the energy of the metal-protein bonding. Interactions of the positively charged monovalent cation with the negatively charged substrate glutamate, Glu 212, Ser 53’, and Asp 50’ could strengthen the active conformation<'''Insert wiki here'''>. Because Ser 53’and Asp 50’reside at the subunit contact surface, the monovalent cation enhances the “side to side” intersubunit interaction.
+Structural stabilization of Glutamine Synthetase by divalent cations, especially by the n1 ion<'''Insert wiki here'''>, has been ascribed to the attraction of their positive charges to the negative charges of glutamate and ATP and of their ligands<'''Insert wiki here'''> (Liaw et al., 1993~).