Sandbox Reserved 346: Difference between revisions
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='''Aspartate Aminotransferase'''= | ='''Aspartate Aminotransferase'''= | ||
==General Information== | ==General Information== | ||
Aspartate Aminotransferase (AST), also know as Glutamic aspartic transaminase, glutamic oxaloacetic transaminase, and transaminase A., is an enzyme that is a member of the class-I pyridoxal-phosphate-dependent aminotransferase family.It is coded by the gene GOT1. It is a homodimer that is 413 amino acids long and serves a critical role in amino acid metabolism. Within prokaryote cells it is exclusively found in the cytosol, but in eukaryotic cells there are cytosol | Aspartate Aminotransferase (AST), also know as Glutamic aspartic transaminase, glutamic oxaloacetic transaminase, and transaminase A., is an enzyme that is a member of the class-I pyridoxal-phosphate-dependent aminotransferase family.It is coded by the gene GOT1. It is a homodimer that is 413 amino acids long and serves a critical role in amino acid metabolism. Within prokaryote cells it is exclusively found in the cytosol, but in eukaryotic cells there are cytosol and mitochondrial isozymes. | ||
<scene name='Sandbox_Reserved_346/Test/1'>Ligand</scene> | <scene name='Sandbox_Reserved_346/Test/1'>Ligand</scene> | ||
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=='''Structure'''== | =='''Structure'''== | ||
<Structure load='1b4x' size='300' frame='true' align='left' caption='Ligand' scene='Sandbox_Reserved_346/Test/1'/> | <Structure load='1b4x' size='300' frame='true' align='left' caption='Ligand' scene='Sandbox_Reserved_346/Test/1'/> | ||
AST is a homodimer that contains 16 alpha helices and a Beta-sheet formed from 7 parallel and antiparallel strands.Each subunit contain an equivalent active site. The subunits connect between their large domains and between the the N-terminal residues and the large domain of the other subunit. This structure of AST varies minutely among organisms rangin from ''E. coli'' to humans. The structure of the active site is highly conserved, and their is a sequence homology of 25%. | |||
Each subunit of the homo dimer is further divided into a samll and large domain. The small domain is comprises of the amino acids from the N-terminus to the Pro 48 residue and from the Met 326 residue to the C-terminus. The remaining amino acids make up the large domain, and the two domains are connected by a long alpha helicx consisting of 32 amino acids. | |||
The large domain is where the active site of AST is found and to accomadate this the core is contains many alpha/beta supersecondary structures. This is contrasted with the core of the small subunit which is fromed from two alpha hellices and two beta strands. In multicellular organisms there is a kink at the 325th residue which acts as a hinge for the samll domain, which allows for the resulting conformational changes that take place upon the binding of inhibitors to the enzyme. | |||
As was stated above, the active site of AST is situated on the large domain of the subunit. Within the active site is the amino residue Lys 258, also known as the intternal aldimine, which binds with the cofactor Pyridoxal 5'-phosphate(<scene name='Sandbox_Reserved_346/PLP/3'>PLP</scene>)forming what is called a Schiff base. Upon addition of an amino acid substrate a new Schiiff base forms between PLP and the amino acid | |||
=='''Function'''== | =='''Function'''== | ||
Revision as of 04:34, 31 March 2011
| This Sandbox is Reserved from January 10, 2010, through April 10, 2011 for use in BCMB 307-Proteins course taught by Andrea Gorrell at the University of Northern British Columbia, Prince George, BC, Canada. |
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| 1b4x, resolution 2.45Å () | |||||||||
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| Ligands: | , | ||||||||
| Activity: | Aspartate transaminase, with EC number 2.6.1.1 | ||||||||
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| Resources: | FirstGlance, OCA, PDBsum, RCSB | ||||||||
| Coordinates: | save as pdb, mmCIF, xml | ||||||||
Aspartate AminotransferaseAspartate Aminotransferase
General InformationGeneral Information
Aspartate Aminotransferase (AST), also know as Glutamic aspartic transaminase, glutamic oxaloacetic transaminase, and transaminase A., is an enzyme that is a member of the class-I pyridoxal-phosphate-dependent aminotransferase family.It is coded by the gene GOT1. It is a homodimer that is 413 amino acids long and serves a critical role in amino acid metabolism. Within prokaryote cells it is exclusively found in the cytosol, but in eukaryotic cells there are cytosol and mitochondrial isozymes.
In the human body it is produced by the brain, skeletal muscles, liver, pancreas, red blood cells, and kidneys. The wide range of tissues in which it is made, separates it from the similar enzyme alanine transaminase (ALT) which is found primarily in the liver. The level of AST in the body can be used as a marker for tissue disease or damage. As well, AST and ALT levels can be compared to pinpoint whether tissue damage is primarily found within the liver.
StructureStructure
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AST is a homodimer that contains 16 alpha helices and a Beta-sheet formed from 7 parallel and antiparallel strands.Each subunit contain an equivalent active site. The subunits connect between their large domains and between the the N-terminal residues and the large domain of the other subunit. This structure of AST varies minutely among organisms rangin from E. coli to humans. The structure of the active site is highly conserved, and their is a sequence homology of 25%.
Each subunit of the homo dimer is further divided into a samll and large domain. The small domain is comprises of the amino acids from the N-terminus to the Pro 48 residue and from the Met 326 residue to the C-terminus. The remaining amino acids make up the large domain, and the two domains are connected by a long alpha helicx consisting of 32 amino acids.
The large domain is where the active site of AST is found and to accomadate this the core is contains many alpha/beta supersecondary structures. This is contrasted with the core of the small subunit which is fromed from two alpha hellices and two beta strands. In multicellular organisms there is a kink at the 325th residue which acts as a hinge for the samll domain, which allows for the resulting conformational changes that take place upon the binding of inhibitors to the enzyme.
As was stated above, the active site of AST is situated on the large domain of the subunit. Within the active site is the amino residue Lys 258, also known as the intternal aldimine, which binds with the cofactor Pyridoxal 5'-phosphate()forming what is called a Schiff base. Upon addition of an amino acid substrate a new Schiiff base forms between PLP and the amino acid