Sandbox Reserved 761: Difference between revisions
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GDH is a homohexamer of 505 residues with a molecular weight of 56 KDa (18). The structure of GDH is essentially two trimers of three identical subunits, totally six subunits, containing three distinct domains; the Glutamate (Glu) binding domain at the N terminus, the NAD binding doman, and the antenna domain, separated by a large active site cleft (9). The overall structure of GDH is composed of eighteen alpha helices and thirteen beta sheets, which are both parallel and anti-parallel. As common to most oxidoreductases the beta sheets are flanked by a layer of alpha helices (18). | GDH is a homohexamer of 505 residues with a molecular weight of 56 KDa (18). The structure of GDH is essentially two trimers of three identical subunits, totally six subunits, containing three distinct domains; the Glutamate (Glu) binding domain at the N terminus, the NAD binding doman, and the antenna domain, separated by a large active site cleft (9). The overall structure of GDH is composed of eighteen alpha helices and thirteen beta sheets, which are both parallel and anti-parallel. As common to most oxidoreductases the beta sheets are flanked by a layer of alpha helices (18). | ||
The bottom domain makes extensive contacts with a subunit from the other trimer. Resting on top of this domain is the 'NAD binding domain' that has the conserved nucleotide-binding motif. | The bottom domain makes extensive contacts with a subunit from the other trimer. Resting on top of this domain is the 'NAD binding domain' that has the conserved nucleotide-binding motif. Human GDH has a long protrusion, an 'antenna' rising above the NAD binding domain. The antenna from each subunit lies immediately behind the adjacent, counter-clockwise neighbour within the trimer. | ||
[[Image:domains.jpg]] | [[Image:domains.jpg]] | ||
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The free energy change for the conversion of glutamate to alpha ketoglutarate is 3.7 kcal/mol (4). Although this ATP-consuming pathway is energetically unfavourable, this could be related to the continuation of re-dox equilibrium to re-oxidise the excess of NADH produced during glycolysis. | The free energy change for the conversion of glutamate to alpha ketoglutarate is 3.7 kcal/mol (4). Although this ATP-consuming pathway is energetically unfavourable, this could be related to the continuation of re-dox equilibrium to re-oxidise the excess of NADH produced during glycolysis. | ||
==Implicatons== | ==Implicatons== | ||
==References== | ==References== | ||
