2okj
From Proteopedia
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==Overview== | ==Overview== | ||
| - | Gamma-aminobutyric acid (GABA) is synthesized by two isoforms of the | + | Gamma-aminobutyric acid (GABA) is synthesized by two isoforms of the pyridoxal 5'-phosphate-dependent enzyme glutamic acid decarboxylase (GAD65 and GAD67). GAD67 is constitutively active and is responsible for basal GABA production. In contrast, GAD65, an autoantigen in type I diabetes, is transiently activated in response to the demand for extra GABA in neurotransmission, and cycles between an active holo form and an inactive apo form. We have determined the crystal structures of N-terminal truncations of both GAD isoforms. The structure of GAD67 shows a tethered loop covering the active site, providing a catalytic environment that sustains GABA production. In contrast, the same catalytic loop is inherently mobile in GAD65. Kinetic studies suggest that mobility in the catalytic loop promotes a side reaction that results in cofactor release and GAD65 autoinactivation. These data reveal the molecular basis for regulation of GABA homeostasis. |
| + | |||
| + | ==Disease== | ||
| + | Known diseases associated with this structure: Cerebral palsy, spastic, symmetric, autosomal recessive OMIM:[[http://www.ncbi.nlm.nih.gov/entrez/dispomim.cgi?id=605363 605363]] | ||
==About this Structure== | ==About this Structure== | ||
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[[Category: Homo sapiens]] | [[Category: Homo sapiens]] | ||
[[Category: Single protein]] | [[Category: Single protein]] | ||
| - | [[Category: Buckle, A | + | [[Category: Buckle, A M.]] |
[[Category: Fenalti, G.]] | [[Category: Fenalti, G.]] | ||
| - | [[Category: Law, R | + | [[Category: Law, R H.P.]] |
| - | [[Category: Whisstock, J | + | [[Category: Whisstock, J C.]] |
[[Category: ABU]] | [[Category: ABU]] | ||
[[Category: PLZ]] | [[Category: PLZ]] | ||
[[Category: plp-dependent decarboxylase]] | [[Category: plp-dependent decarboxylase]] | ||
| - | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 18:19:29 2008'' |
Revision as of 16:19, 21 February 2008
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The X-ray crystal structure of the 67kDa isoform of Glutamic Acid Decarboxylase (GAD67)
Contents |
Overview
Gamma-aminobutyric acid (GABA) is synthesized by two isoforms of the pyridoxal 5'-phosphate-dependent enzyme glutamic acid decarboxylase (GAD65 and GAD67). GAD67 is constitutively active and is responsible for basal GABA production. In contrast, GAD65, an autoantigen in type I diabetes, is transiently activated in response to the demand for extra GABA in neurotransmission, and cycles between an active holo form and an inactive apo form. We have determined the crystal structures of N-terminal truncations of both GAD isoforms. The structure of GAD67 shows a tethered loop covering the active site, providing a catalytic environment that sustains GABA production. In contrast, the same catalytic loop is inherently mobile in GAD65. Kinetic studies suggest that mobility in the catalytic loop promotes a side reaction that results in cofactor release and GAD65 autoinactivation. These data reveal the molecular basis for regulation of GABA homeostasis.
Disease
Known diseases associated with this structure: Cerebral palsy, spastic, symmetric, autosomal recessive OMIM:[605363]
About this Structure
2OKJ is a Single protein structure of sequence from Homo sapiens with and as ligands. Active as Glutamate decarboxylase, with EC number 4.1.1.15 Full crystallographic information is available from OCA.
Reference
GABA production by glutamic acid decarboxylase is regulated by a dynamic catalytic loop., Fenalti G, Law RH, Buckle AM, Langendorf C, Tuck K, Rosado CJ, Faux NG, Mahmood K, Hampe CS, Banga JP, Wilce M, Schmidberger J, Rossjohn J, El-Kabbani O, Pike RN, Smith AI, Mackay IR, Rowley MJ, Whisstock JC, Nat Struct Mol Biol. 2007 Apr;14(4):280-6. Epub 2007 Mar 25. PMID:17384644
Page seeded by OCA on Thu Feb 21 18:19:29 2008
