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.
1ehw
From Proteopedia
OCA (Talk | contribs)
(New page: 200px<br /> <applet load="1ehw" size="450" color="white" frame="true" align="right" spinBox="true" caption="1ehw, resolution 2.40Å" /> '''HUMAN NUCLEOSIDE DI...)
Next diff →
Revision as of 14:37, 12 November 2007
|
HUMAN NUCLEOSIDE DIPHOSPHATE KINASE 4
Overview
We demonstrate here the catalytic activity and subcellular localization of, the Nm23-H4 protein, product of nm23-H4, a new member of the human, nm23/nucleoside diphosphate (NDP) kinase gene family (Milon, L., Rousseau-Merck, M., Munier, A., Erent, M., Lascu, I., Capeau, J., and, Lacombe, M. L. (1997) Hum. Genet. 99, 550-557). Nm3-H4 was synthesized in, escherichia coli as the full-length protein and as a truncated form, missing the N-terminal extension characteristic of mitochondrial, targeting. The truncated form possesses NDP kinase activity, whereas the, full-length protein is inactive, suggesting that the extension prevents, enzyme folding and/or activity. X-ray crystallographic analysis was, performed on active truncated Nm23-H4. Like other eukaryotic NDP kinases, it is a hexamer. Nm23-H4 naturally possesses a serine residue at position, 129, equivalent to the K-pn mutation of the Drosophila NDP kinase. The, x-ray structure shows that the presence of Ser(129) has local structural, effects that weaken subunit interactions. Site-directed mutagenesis shows, that the serine is responsible for the lability of Nm23-H4 to heat and, urea treatment, because the S129P mutant is greatly stabilized., Examination of human embryonic kidney 293 cells transfected with green, fluorescent protein fusions by confocal microscopy shows a specific, mitochondrial localization of Nm23-H4 that was also demonstrated by, Western blot analysis of subcellular fractions of these cells. Import into, mitochondria is accompanied by cleavage of the N-terminal extension that, results in NDP kinase activity. Submitochondrial fractionation indicates, that Nm23-H4 is associated with mitochondrial membranes, possibly to the, contact sites between the outer and inner membranes.
About this Structure
1EHW is a Single protein structure of sequence from Homo sapiens with SO4 as ligand. Active as Nucleoside-diphosphate kinase, with EC number 2.7.4.6 Full crystallographic information is available from OCA.
Reference
The human nm23-H4 gene product is a mitochondrial nucleoside diphosphate kinase., Milon L, Meyer P, Chiadmi M, Munier A, Johansson M, Karlsson A, Lascu I, Capeau J, Janin J, Lacombe ML, J Biol Chem. 2000 May 12;275(19):14264-72. PMID:10799505
Page seeded by OCA on Mon Nov 12 16:43:44 2007
