Sandbox Reserved 477: Difference between revisions
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<Structure load='1VC2' size='500' frame='true' align='right' caption='This is Glyceraldehyde-3-Phosphate Dehydrogenase isolated from Thermus thermophilus HB8' scene='Insert optional scene name here' /> | <Structure load='1VC2' size='500' frame='true' align='right' caption='This is Glyceraldehyde-3-Phosphate Dehydrogenase isolated from Thermus thermophilus HB8' scene='Insert optional scene name here' /> | ||
'''Structure''' | '''Structure''' | ||
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Glyceraldehyde-3-Phosphate Dehydrogenase is a homotetramer and has chains of exactly the same sequence and structure. Depending on the isoform of GAPDH, there are different numbers of secondary structures; however, the more common GAPDHs have 14 <scene name='Sandbox_Reserved_477/Helix/1'>helices</scene> and 13 <scene name='Sandbox_Reserved_477/Beta_sheet/1'>beta strands</scene>. Evolutionary change for GAPDH is very slow, so there is high sequence similarity between bacterial and eukaryotic GAPDHs. Though not shown, the residue Cysteine 139 is the active site at the C end of the alpha helix 138-153. In bacteria and eukaryotes, a His 176 is conserved. The histidine is believed to act as a base that extracts a proton from the Cys 139 during catalysis. | Glyceraldehyde-3-Phosphate Dehydrogenase is a homotetramer and has chains of exactly the same sequence and structure. Depending on the isoform of GAPDH, there are different numbers of secondary structures; however, the more common GAPDHs have 14 <scene name='Sandbox_Reserved_477/Helix/1'>helices</scene> and 13 <scene name='Sandbox_Reserved_477/Beta_sheet/1'>beta strands</scene>. Evolutionary change for GAPDH is very slow, so there is high sequence similarity between bacterial and eukaryotic GAPDHs. Though not shown, the residue Cysteine 139 is the active site at the C end of the alpha helix 138-153. In bacteria and eukaryotes, a His 176 is conserved. The histidine is believed to act as a base that extracts a proton from the Cys 139 during catalysis. | ||
NAD+ is the most common <scene name='Sandbox_Reserved_477/Ligand/1'>ligand</scene> for the binding of GAPDH. A ligand is a molecule that binds to a central atom to form a complex. NAD+ expresses negative cooperativity in relation to GAPDH; as NAD+ binds to the protein, the protein's affinity for the ligand decreases. | NAD+ is the most common <scene name='Sandbox_Reserved_477/Ligand/1'>ligand</scene> for the binding of GAPDH. A ligand is a molecule that binds to a central atom to form a complex. NAD+ expresses negative cooperativity in relation to GAPDH; as NAD+ binds to the protein, the protein's affinity for the ligand decreases. | ||
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<scene name='Sandbox_Reserved_477/Hydrophobic_residues/1'>hydrophobic residues</scene> | <scene name='Sandbox_Reserved_477/Hydrophobic_residues/1'>hydrophobic residues</scene> | ||
'''Diseases''' | '''Diseases''' | ||
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Glyceraldehyde-3-Phosphate Dehydrogenase deficiency is a rare genetic disorder in which an individual has a deficiency of GAPDH, which is heavily involved in breaking down carbohydrates consumed in the diet in order to produce energy. This condition is asymptomatic and affects less than 200,000 people in the United States. GAPDH deficiency also occurs in plants, known as plastidial GAPDH deficiency. In plants, glycolysis occurs in both the cytosol and plastids. In a chloroplast/plastid-localized GAPDH isoform, gapcp, these double mutants have produced drastic phenotypes of arrested root development, dwarfism, and sterility. | Glyceraldehyde-3-Phosphate Dehydrogenase deficiency is a rare genetic disorder in which an individual has a deficiency of GAPDH, which is heavily involved in breaking down carbohydrates consumed in the diet in order to produce energy. This condition is asymptomatic and affects less than 200,000 people in the United States. GAPDH deficiency also occurs in plants, known as plastidial GAPDH deficiency. In plants, glycolysis occurs in both the cytosol and plastids. In a chloroplast/plastid-localized GAPDH isoform, gapcp, these double mutants have produced drastic phenotypes of arrested root development, dwarfism, and sterility. | ||
[[Image:Alisha.jpg | thumb]] | [[Image:Alisha.jpg | thumb]] | ||
'''Mechanism of Action''' | '''Mechanism of Action''' | ||
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The mechanism using GAPDH to convert glyceraldehyde-3-phosphate into 1,3-bisphosphoglycerate in the sixth step of glycolysis is a two step process. The first reaction is the oxidation of glyceraldehyde-3-phosphate at the 1st carbon position. At this position, an aldehyde is converted into a carboxylic acid while NAD+ is simultaneously reduced to NADH. This reaction is energetically favorable with a Gibb's free energy of -50kJ/mol. The energy released by the first reaction drives the second reaction. In the second reaction, a molecule of inorganic phosphate is transferred to the intermediate to form the final product of this reaction that has a high phosphoryl-transfer reaction, 1,3-bisphosphoglycerate. | The mechanism using GAPDH to convert glyceraldehyde-3-phosphate into 1,3-bisphosphoglycerate in the sixth step of glycolysis is a two step process. The first reaction is the oxidation of glyceraldehyde-3-phosphate at the 1st carbon position. At this position, an aldehyde is converted into a carboxylic acid while NAD+ is simultaneously reduced to NADH. This reaction is energetically favorable with a Gibb's free energy of -50kJ/mol. The energy released by the first reaction drives the second reaction. In the second reaction, a molecule of inorganic phosphate is transferred to the intermediate to form the final product of this reaction that has a high phosphoryl-transfer reaction, 1,3-bisphosphoglycerate. | ||
