This old version of Proteopedia is provided for student assignments while the new version is undergoing repairs. Content and edits done in this old version of Proteopedia after March 1, 2026 will eventually be lost when it is retired in about June of 2026.
Apply for new accounts at the new Proteopedia. Your logins will work in both the old and new versions.
2h2n
From Proteopedia
| Line 1: | Line 1: | ||
[[Image:2h2n.gif|left|200px]] | [[Image:2h2n.gif|left|200px]] | ||
| - | + | <!-- | |
| - | + | The line below this paragraph, containing "STRUCTURE_2h2n", creates the "Structure Box" on the page. | |
| - | + | You may change the PDB parameter (which sets the PDB file loaded into the applet) | |
| - | + | or the SCENE parameter (which sets the initial scene displayed when the page is loaded), | |
| - | + | or leave the SCENE parameter empty for the default display. | |
| - | | | + | --> |
| - | | | + | {{STRUCTURE_2h2n| PDB=2h2n | SCENE= }} |
| - | + | ||
| - | + | ||
| - | }} | + | |
'''Crystal structure of human soluble calcium-activated nucleotidase (SCAN) with calcium ion''' | '''Crystal structure of human soluble calcium-activated nucleotidase (SCAN) with calcium ion''' | ||
| Line 30: | Line 27: | ||
[[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 05:47:55 2008'' | |
| - | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on | + | |
Revision as of 02:47, 4 May 2008
Crystal structure 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
2H2N 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 05:47:55 2008
