1m9i
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(New page: 200px<br /> <applet load="1m9i" size="450" color="white" frame="true" align="right" spinBox="true" caption="1m9i, resolution 2.65Å" /> '''Crystal Structure O...)
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Revision as of 16:02, 12 November 2007
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Crystal Structure Of Phosphorylation-Mimicking Mutant T356D Of Annexin VI
Overview
Phosphorylation of some members of the annexin family of proteins may play, a significant role in controlling their calcium-dependent interactions, with membranes. Recent electron microscopic studies of annexin VI revealed, that the protein's two core domains exhibit a great degree of flexibility, and are able to undergo a relative conformational change that could, potentially initiate contacts between membranes [Avila-Sakar, A. J., et, al. (2000) J. Struct. Biol. 130, 54-62]. To assess the possibility of a, regulatory role of phosphorylation in this behavior, the crystal structure, of a phosphorylation-mimicking mutant (T356D in the flexible connector, region of human annexin VI) was determined to 2.65 A resolution. When the, mutant is compared to the wild-type annexin VI, subtle differences are, seen at the site of the mutation, while larger changes are evident in one, of the calcium-binding loops and in the presence of five calcium ions., Furthermore, biochemical studies provide evidence for additional, conformational differences between the T356D and wild-type solution, structures. Fluorescence emission and acrylamide quenching suggest a, higher level of solvent exposure of Trp-343 in the connector region of, T356D in the presence of calcium. Comparisons of retardation coefficients, in native gel electrophoresis reveal that T356D has a more extended shape, while proteolytic studies show a greater accessibility of a trypsin, cleavage site inside the linker region, indicating a conformation more, open than the wild-type form. These data provide insights into a possible, regulatory mechanism leading to a higher degree of flexibility and, possibly a higher calcium binding affinity of annexin VI upon, phosphorylation.
About this Structure
1M9I is a Single protein structure of sequence from Homo sapiens with CA as ligand. Full crystallographic information is available from OCA.
Reference
Structural and dynamic changes in human annexin VI induced by a phosphorylation-mimicking mutation, T356D., Freye-Minks C, Kretsinger RH, Creutz CE, Biochemistry. 2003 Jan 28;42(3):620-30. PMID:12534274
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