1n00
From Proteopedia
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Annexin Gh1 from cotton
Overview
The three-dimensional crystal structure of recombinant annexin Gh1 from, Gossypium hirsutum (cotton fibre) has been determined and refined to the, final R-factor of 0.219 at the resolution of 2.1 A. This plant annexin, consists of the typical 'annexin fold' and is similar to the previously, solved bell pepper annexin Anx24(Ca32), but significant differences are, seen when compared to the structure of nonplant annexins. A comparison, with the structure of the mammalian annexin AnxA5 indicates that canonical, calcium binding is geometrically possible within the membrane loops in, domains I and II of Anx(Gh1) in their present conformation. All plant, annexins possess a conserved tryptophan residue in the AB loop of the, first domain; this residue was found to adopt both a loop-in and a, loop-out conformation in the bell pepper annexin Anx24(Ca32). In Anx(Gh1), the conserved tryptophan residue is in a surface-exposed position, half, way between both conformations observed in Anx24(Ca32). The present, structure reveals an unusual sulfur cluster formed by two cysteines and a, methionine in domains II and III, respectively. While both cysteines adopt, the reduced thiolate forms and are separated by a distance of about 5.5 A, the sulfur atom of the methionine residue is in their close vicinity and, apparently interacts with both cysteine sulfur atoms. While the cysteine, residues are conserved in at least five plant annexins and in several, mammalian members of the annexin family of proteins, the methionine, residue is conserved only in three plant proteins. Several of these, annexins carrying the conserved residues have been implicated in oxidative, stress response. We therefore hypothesize that the cysteine motif found in, the present structure, or possibly even the entire sulfur cluster, forms, the molecular basis for annexin function in oxidative stress response.
About this Structure
1N00 is a Single protein structure of sequence from Gossypium hirsutum with SO4 as ligand. Full crystallographic information is available from OCA.
Reference
The crystal structure of annexin Gh1 from Gossypium hirsutum reveals an unusual S3 cluster., Hofmann A, Delmer DP, Wlodawer A, Eur J Biochem. 2003 Jun;270(12):2557-64. PMID:12787021
Page seeded by OCA on Sat Nov 24 22:17:51 2007
