1EHW

HUMAN NUCLEOSIDE DIPHOSPHATE KINASE 4

Summary for 1EHW

• Entry DOI: 10.2210/pdb1ehw/pdb
• Descriptor: NUCLEOSIDE DIPHOSPHATE KINASE, SULFATE ION (3 entities in total)
• Functional Keywords: nucleoside diphosphate kinase, nm23, mitochondrial, killer-of-prune, transferase
• Biological source: Homo sapiens (human)
• Cellular location: Mitochondrion intermembrane space ; Peripheral membrane protein: O00746
• Total number of polymer chains: 2
• Total formula weight: 36707.62

Authors

Milon, L.,Meyer, P.,Chiadmi, M.,Munier, A.,Johansson, M.,Karlsson, A.,Lascu, I.,Capeau, J.,Janin, J.,Lacombe, M.-L. (deposition date: 2000-02-23, release date: 2000-05-17, Last modification date: 2024-02-07)

Primary citation

Milon, L.,Meyer, P.,Chiadmi, M.,Munier, A.,Johansson, M.,Karlsson, A.,Lascu, I.,Capeau, J.,Janin, J.,Lacombe, M.L.
The human nm23-H4 gene product is a mitochondrial nucleoside diphosphate kinase.
J.Biol.Chem., 275:14264-14272, 2000

PubMed Abstract: 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.

PubMed: 10799505
DOI: 10.1074/jbc.275.19.14264

Experimental method

X-RAY DIFFRACTION (2.4 Å)