User:Vincent de Chavez/Sandbox 3
From Proteopedia
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== Structure == | == Structure == | ||
| - | The amino acid mutations that give superfolder GFP its durability are located within the protein's beta-can structure, away from the central chromophore. Wild-type GFP possesses a serine residue on beta strand S2 at position 30, which is mutated to arginine in superfolder GFP, changing the local conformation and interactions with four key surrounding residues. A five-membered ion-pair network of alternating acidic and basic charges is created by <scene name='User:Vincent_de_Chavez/Sandbox_3/Superfoldermutation/3'>Glu32, Arg30, Glu17, Arg122, and Glu115</scene>. This system of residues is the ultimate source of superfolder GFP's increased stability, with arginine as the main director of the arrangement. Arginine's ability to participate in double salt bridges to glutamic acid or other arginine residues allows for the electrostatic interactions that eliminate aggregation issues and make this protein the fastest and best-folding variant. Other benefits of the mutation include fluorescence twice that of wild-type GFP and resistance to the deleterious effects of random mutation. | + | The amino acid mutations that give superfolder GFP its durability are located within the protein's beta-can structure, away from the central chromophore. Wild-type GFP possesses a serine residue on beta strand S2 at position 30, which is mutated to arginine in superfolder GFP, changing the local conformation and interactions with four key surrounding residues. A five-membered ion-pair network of alternating acidic and basic charges is created by <scene name='User:Vincent_de_Chavez/Sandbox_3/Superfoldermutation/3'>Glu32, Arg30, Glu17, Arg122, and Glu115</scene>. The arginine mutation of serine 30 is shown in magenta. This system of residues is the ultimate source of superfolder GFP's increased stability, with arginine as the main director of the arrangement. Arginine's ability to participate in double salt bridges to glutamic acid or other arginine residues allows for the electrostatic interactions that eliminate aggregation issues and make this protein the fastest and best-folding variant. Other benefits of the mutation include fluorescence twice that of wild-type GFP and resistance to the deleterious effects of random mutation. |
Revision as of 01:03, 16 March 2009
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Background
Green Fluorescent Protein (GFP) is a valuable tool in cellular and molecular biology, largely because of the self-fluorescing properties of its chromophore. This fluorescence permits the molecule to function as a protein fusion tag in bacterial cells. Wild-type GFP and many of its mutant variants tend to misfold when used as protein fusion tags, often due to poor folding of the bacterial proteins themselves, which then hinders GFP from assuming its proper conformation and causes it to aggregate and display weaker fluorescence. Consequently, a “robustly folded” GFP variant, called superfolder GFP, was developed to withstand any folding complications of the protein it was designed to tag.
Structure
The amino acid mutations that give superfolder GFP its durability are located within the protein's beta-can structure, away from the central chromophore. Wild-type GFP possesses a serine residue on beta strand S2 at position 30, which is mutated to arginine in superfolder GFP, changing the local conformation and interactions with four key surrounding residues. A five-membered ion-pair network of alternating acidic and basic charges is created by . The arginine mutation of serine 30 is shown in magenta. This system of residues is the ultimate source of superfolder GFP's increased stability, with arginine as the main director of the arrangement. Arginine's ability to participate in double salt bridges to glutamic acid or other arginine residues allows for the electrostatic interactions that eliminate aggregation issues and make this protein the fastest and best-folding variant. Other benefits of the mutation include fluorescence twice that of wild-type GFP and resistance to the deleterious effects of random mutation.
