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Mitochondrial NDP kinase from Dunaliella tertiolecta (Chlorophyceae, Chlorophyta)
Author(s) -
Anderca Marinela I.,
Furuichi Takuya,
Muto Shoshi
Publication year - 2003
Publication title -
phycological research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.438
H-Index - 44
eISSN - 1440-1835
pISSN - 1322-0829
DOI - 10.1046/j.1440-1835.2003.00304.x
Subject(s) - biology , biochemistry , chlorophyceae , chlorophyta , enzyme , microbiology and biotechnology , botany , algae
SUMMARY A cDNA ( DtNDK1 ) encoding a nucleoside diphosphate (NDP) kinase with a putative mitochondrial targeting signal sequence was previously isolated from the halo‐tolerant green alga Dunaliella tertiolecta . When expressed in Saccharomyces cerevisiae , the processed DtNDK1 enzyme was specifically localized to mitochondria. The present study reports several biochemical characteristics of the mitochondrial NDP kinase from D. tertiolecta . The mature protein was expressed as either N‐ or C‐terminal hexahistidine‐tagged protein and purified to homogeneity by affinity chromato‐graphy. Native gel electrophoresis and sedimentation velocity in sucrose density gradients showed that the active enzyme consisted of a hexamer. The enzyme, with a pH optimum of 7, showed the highest specificity to dCDP ( K m = 50 μ m ol/L) and the highest turnover towards the synthesis of UTP (up to 140‐fold higher). The present study also provides evidence that purified DtNDK1 proteins are capable of transferring a phosphate group to another protein.