| Literature References | 1. BARTON, G.J., NEWMAN, R.H., FREEMONT, P.S. AND CRUMPTON, M.J.
Amino acid sequence analysis of the annexin super-gene family of proteins.
EUR.J.BIOCHEM. 198 749-760 (1991).
2. BRAUN, E.L., KANG, S., NELSON, M.A. AND NATVIG, D.O.
Identification of the first fungal annexin: analysis of annexin gene
duplications and implications for eukaryotic evolution.
J.MOL.EVOL. 47 531-543 (1998).
3. BENZ, J. AND HOFMANN, A.
Annexins: from structure to function.
BIOL.CHEM. 378 177-183 (1997).
4. GEISOW, M.J.
Annexins-forms without function but not without fun.
TRENDS BIOTECHNOL. 9 180-181 (1991).
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| Documentation | The annexins (or lipocortins) are a family of proteins that bind to
phospholipids in a calcium-dependent manner [1]. They are distributed
ubiquitously in different tissues and cell types of higher and lower
eukaryotes, including mammals, fish, birds, Drosophila melanogaster,
Xenopus laevis, Caenorhabtidis elegans, Dictyostelium discoideum and
Neurospora crassa [2,3]. The plant annexins are somewhat distinct from
those found in other taxa [3].
Several distinct annexin subtypes exist, each of which has an amino-acid
sequence consisting of an N-terminal 'arm' followed by 4 or 8 copies of a
conserved domain of 61 residues (only one of these residues, an arginine,
is conserved between all copies). The calcium-binding sites are found in
the repeated domains [4]. Individual repeats (sometimes referred to as
endonexin folds) consist of 5 alpha-helices wound into a right-handed
superhelix. The biological roles of some annexin subtypes is unclear; the
family has been linked with inhibition of phospholipase activity, exo-
cytosis and endoctyosis, signal transduction, organisation of the extra-
cellular matrix, resistance to reactive oxygen species and DNA replication
[2]. Type V annexin behaves as an anticoagulant, acting as an indirect
inhibitor of the thromboplastin-specific complex, which is involved in the
blood coagulation casacade. It may also act as a form of calcium channel.
ANNEXINV is a 4-element fingerprint that provides a signature for type V
annexins. The fingerprint was derived from an initial alignment of 7
sequences: the motifs were drawn from conserved regions spanning virtually
the full alignment length, focusing on those areas that characterise type
V annexins but distinguish them from related annexin subtypes - motif 1
resides in the second annexin repeat; motif 2 lies between the second and
third repeats; and motifs 3 and 4 are located in the third and fourth
repeats, respectively. Two iterations on SPTR41_24f were required to
reach convergence, at which point a true set comprising 9 sequences was
identified. Five partial matches were also found, including a type V
annexin, Q804G6, several related subtypes and a hypothetical protein,
Q803A1, from Danio rerio.
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