Sandbox Reserved 1094: Difference between revisions
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This sequence being the normal protein sequence found in L. ''mesenteroides''. | This sequence being the normal protein sequence found in L. ''mesenteroides''. | ||
<Structure load='1dpg' size='450' frame='true' align='right' caption='Insert caption here' scene='' /> | |||
== Structural highlights == | == Structural highlights == | ||
Glucose-6-Phosphate Dehydrogenase is formed of a homodimer, so a dimer of two identical [https://en.wikipedia.org/wiki/Protein_subunit subunit]. | Glucose-6-Phosphate Dehydrogenase is formed of a homodimer, so a dimer of two identical [https://en.wikipedia.org/wiki/Protein_subunit subunit]. | ||
'''Secondary structure''' | ==='''Secondary structure'''=== | ||
A subunit contains 485 residues where 285 residues are in secondary structure. 93 residues are involved in 15 β-sheet strands and 192 in 17 helices. | A subunit contains 485 residues where 285 residues are in secondary structure. 93 residues are involved in 15 β-sheet strands and 192 in 17 helices. | ||
'''Tertiary structure''' | ==='''Tertiary structure'''=== | ||
Each <scene name='82/829347/Monomerg6pd/1'>monomer</scene> is composed of 2 domains, <scene name='82/829347/Homodimer_g6pd/5'>1 red and 1 green</scene>. | Each <scene name='82/829347/Monomerg6pd/1'>monomer</scene> is composed of 2 domains, <scene name='82/829347/Homodimer_g6pd/5'>1 red and 1 green</scene>. | ||
Each monomer is composed of a small domain localized in the amino terminal part (residues 1-177) which constitute the coenzyme binding domain and a larger domain in the carboxyl terminal part (residues 178-485).<ref name="struc">PMID: 7881907</ref> | Each monomer is composed of a small domain localized in the amino terminal part (residues 1-177) which constitute the coenzyme binding domain and a larger domain in the carboxyl terminal part (residues 178-485).<ref name="struc">PMID: 7881907</ref> | ||
====''Coenzyme binding domain''==== | |||
The coenzyme binding domain binds the [https://en.wikipedia.org/wiki/Nicotinamide_adenine_dinucleotide NAD] or [https://en.wikipedia.org/wiki/Nicotinamide_adenine_dinucleotide_phosphate NADP] which participes in the dehydrogenation of '''G6P'''. | The coenzyme binding domain binds the [https://en.wikipedia.org/wiki/Nicotinamide_adenine_dinucleotide NAD] or [https://en.wikipedia.org/wiki/Nicotinamide_adenine_dinucleotide_phosphate NADP] which participes in the dehydrogenation of '''G6P'''. | ||
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Arg46 is strcilty conserved and involved in the binding with the 2'-phosphate of NADP. Gln47 could interact both with the 2'-phosphate of NADP or with the 2'-hydroxyl of NAD. | Arg46 is strcilty conserved and involved in the binding with the 2'-phosphate of NADP. Gln47 could interact both with the 2'-phosphate of NADP or with the 2'-hydroxyl of NAD. | ||
====''Carboxyl terminus domain''==== | |||
The carboxyl terminus domain is defined by a β+α particular fold which has created his own fold family the [https://scop.berkeley.edu/sunid=39989 G6PD-like]. It is composed of a large essentially antiparallel curved nine-stranded β-sheet with 11 helices and remain well ordered to the carboxy-terminal residue. It is essential in the activity of the enzyme because it ensure the formation of the tertiary and the quaternary structure. | The carboxyl terminus domain is defined by a β+α particular fold which has created his own fold family the [https://scop.berkeley.edu/sunid=39989 G6PD-like]. It is composed of a large essentially antiparallel curved nine-stranded β-sheet with 11 helices and remain well ordered to the carboxy-terminal residue. It is essential in the activity of the enzyme because it ensure the formation of the tertiary and the quaternary structure. | ||
====''Domain boundary''==== | |||
At the boundary between the two domains some helices of the carboxy terminus domain interacts with multiples β strands and helices of the coenzyme binding domain ensuring the cohesion of the enzyme monomer. | At the boundary between the two domains some helices of the carboxy terminus domain interacts with multiples β strands and helices of the coenzyme binding domain ensuring the cohesion of the enzyme monomer. | ||
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Asp177 and His240 are two basic residues conserved and localized in the binding pocket which could act as base for the deshydrogenation reaction. Site-directed mutagenesis has shown that H240N mutant have a lower activity than the wild-type enzyme. So it has been deduced that His240 is involved as the base of the reaction. | Asp177 and His240 are two basic residues conserved and localized in the binding pocket which could act as base for the deshydrogenation reaction. Site-directed mutagenesis has shown that H240N mutant have a lower activity than the wild-type enzyme. So it has been deduced that His240 is involved as the base of the reaction. | ||
'''Quaternary structure''' | ==='''Quaternary structure'''=== | ||
''Dimer'' | ''Dimer'' | ||
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The active site of the enzyme is contained in each monomer but the dimeric form is necessary to the biological activity indeed it confers the stability in aqueous medium. | The active site of the enzyme is contained in each monomer but the dimeric form is necessary to the biological activity indeed it confers the stability in aqueous medium. | ||
== References == | == References == | ||
<references/> | <references/> | ||
