Biochemical characterization of tomato annexin p35 : independence of calcium-binding and phosphatase activities

Lim, Eng-Kiat and Roberts, Michael and Bowles, D. J. (1999) Biochemical characterization of tomato annexin p35 : independence of calcium-binding and phosphatase activities. Journal of Biological Chemistry, 273 (52). 34920–34925. ISSN 1083-351X

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Abstract

Tomato annexin p35 has been cloned and used in a site-directed mutagenesis study to explore the phospholipid binding and catalytic properties of the protein in detail. Analysis of the cDNA sequence of p35 reveals that the annexin has only two typical endonexin folds, corresponding to repeats I and IV. Expression of recombinant p35 in Escherichia coli confirmed both phospholipid binding and a nucleotide phosphatase activity that could be inhibited on interaction of the recombinant annexin with phospholipids. Site-directed mutagenesis in which the acidic residues Glu-68 (repeat I), and Asp-297 (repeat IV) were changed to Asn, generated two mutant forms, E68N and D297N, respectively. Both mutant forms of the annexin continued to express catalytic activity. Changing repeat I had little effect on phospholipid binding, whereas the change to repeat IV abolished this property. These data show that, in this plant annexin, repeat IV plays a more critical role in calcium-dependent phospholipid binding than repeat I, and that the catalytic and phospholipid binding activity of the protein can be separated experimentally.

Item Type:
Journal Article
Journal or Publication Title:
Journal of Biological Chemistry
Uncontrolled Keywords:
/dk/atira/pure/subjectarea/asjc/1300/1303
Subjects:
?? annexincalciumphosphatasebiochemistrycell biologymolecular biology ??
ID Code:
49854
Deposited By:
Deposited On:
20 Sep 2011 08:36
Refereed?:
Yes
Published?:
Published
Last Modified:
15 Jul 2024 12:19