2h2u
From Proteopedia
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| - | + | {{STRUCTURE_2h2u| PDB=2h2u | SCENE= }} | |
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'''Crystal structure of the E130Y mutant of human soluble calcium-activated nucleotidase (SCAN) with calcium ion''' | '''Crystal structure of the E130Y mutant of human soluble calcium-activated nucleotidase (SCAN) with calcium ion''' | ||
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[[Category: Kirley, T L.]] | [[Category: Kirley, T L.]] | ||
[[Category: Yang, M.]] | [[Category: Yang, M.]] | ||
| - | [[Category: | + | [[Category: Calcium-binding protein]] |
| - | [[Category: | + | [[Category: Five-blade beta propeller]] |
| - | [[Category: | + | [[Category: Nucleotidase]] |
| - | [[Category: | + | [[Category: Nucleotide-binding]] |
| - | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sun May 4 05:48:11 2008'' | |
| - | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on | + | |
Revision as of 02:48, 4 May 2008
Crystal structure of the E130Y mutant of human soluble calcium-activated nucleotidase (SCAN) with calcium ion
Overview
Mammals express a protein homologous to soluble nucleotidases used by blood-sucking insects to inhibit host blood clotting. These vertebrate nucleotidases may play a role in protein glycosylation. The activity of this enzyme family is strictly dependent on calcium, which induces a conformational change in the secreted, soluble human nucleotidase. The crystal structure of this human enzyme was recently solved; however, the mechanism of calcium activation and the basis for the calcium-induced changes remain unclear. In this study, using analytical ultracentrifugation and chemical cross-linking, we show that calcium or strontium induce noncovalent dimerization of the soluble human enzyme. The location and nature of the dimer interface was elucidated using a combination of site-directed mutagenesis and chemical cross-linking, coupled with crystallographic analyses. Replacement of Ile(170), Ser(172), and Ser(226) with cysteine residues resulted in calcium-dependent, sulfhydryl-specific intermolecular cross-linking, which was not observed after cysteine introduction at other surface locations. Analysis of a super-active mutant, E130Y, revealed that this mutant dimerized more readily than the wild-type enzyme. The crystal structure of the E130Y mutant revealed that the mutated residue is found in the dimer interface. In addition, expression of the full-length nucleotidase revealed that this membrane-bound form can also dimerize and that these dimers are stabilized by spontaneous oxidative cross-linking of Cys(30), located between the single transmembrane helix and the start of the soluble sequence. Thus, calcium-mediated dimerization may also represent a mechanism for regulation of the activity of this nucleotidase in the physiological setting of the endoplasmic reticulum or Golgi.
About this Structure
2H2U is a Single protein structure of sequence from Homo sapiens. Full crystallographic information is available from OCA.
Reference
Calcium-dependent dimerization of human soluble calcium activated nucleotidase: characterization of the dimer interface., Yang M, Horii K, Herr AB, Kirley TL, J Biol Chem. 2006 Sep 22;281(38):28307-17. Epub 2006 Jul 11. PMID:16835225 Page seeded by OCA on Sun May 4 05:48:11 2008
