This entry represents a group of plant proteins, including nodulin homeobox protein (NDX) from Arabidopsis. AtNDX associates with single-stranded DNA and inhibits COOLAIR transcription, which in turn modifies FLC (FLOWERING LOCUS C) expression [
].
This family consists of several plant specific late nodulin sequences which are homologous to the Pisum sativum (Garden pea) ENOD3 protein. ENOD3 is expressed in the late stages of root nodule formation and contains two pairs of cysteine residues toward the proteins C terminus which may be involved in metal-binding [
].
The expression of early nodulin (ENOD) genes has been well characterised in several legume species. Based on their biochemical attributes and expression
patterns, they are postulated to have roles in cell structure, in the control of nodule ontogeny by the degradation of Nod factor, and in carbon metabolism [].
The soybean early nodulin 40 (ENOD40) mRNA contains two short overlapping ORFs; in vitro translation yields two peptides of 12 and 24 amino acids [
]. The putative role of the ENOD40 genes has been in favour of organogenesis, such as induction of the cortical cell divisions that lead to initiation of nodule primordia, in developing lateral roots and embryonic tissues. This supports the hypothesis for a role of ENOD40 in lateral organ development [].
Mavicyanin is a glycosylated protein isolated from Cucurbita pepo medullosa (zucchini) peelings. It belongs to the phytocyanin family of blue copper proteins, a ubiquitous family of plant cupredoxins. Mavicyanin is involved in electron transfer reactions with the Cu centre transitioning between the oxidized Cu(II) form and the reduced Cu(I) form. The copper is tetrahedrally coordinated by a cysteine, 2 histidines, and a glutamine residue, like in the case of stellacyanin. The biological roles of mavicyanin have not been elucidated yet [
,
,
,
].Phytocyanins are classified into four groups: stellacyanin, plantacyanin, uclacyanin and early nodulin groups. The domain architecture of mavicyanin reveals that it is a member of the stellacyanin group [
].
A number of proteins involved in the transport of sulphate across a membrane
as well as some yet uncharacterised proteins have been shown [,
] to be evolutionary related.These proteins are:
Neurospora crassa sulphate permease II (gene cys-14).Yeast sulphate permeases (genes SUL1 and SUL2).Rat sulphate anion transporter 1 (SAT-1).Mammalian DTDST, a probable sulphate transporter which, in human, is involved in the genetic disease, diastrophic dysplasia (DTD).Sulphate transporters 1, 2 and 3 from the legume Stylosanthes hamata.Human pendrin (gene PDS), which is involved in a number of hearing loss genetic diseases.Human protein DRA (Down-Regulated in Adenoma).Soybean early nodulin 70.Escherichia coli hypothetical protein ychM.Caenorhabditis elegans hypothetical protein F41D9.5.These proteins are highly hydrophobic and seem to contain about 12 transmembrane domains.
This entry represents a conserved domain found in a group of sulphate transporters, known as the SLC26A/SulP family [
,
]. These proteins contain an N-terminal membrane domain and a C-terminal cytoplasmic STAS domain a STAS (sulfate transporter and anti-sigma factor antagonist) domain []. This central domain is usually found next to the STAS domain (). Proteins containing this domain include:
Neurospora crassa sulphate permease II (gene cys-14).Yeast sulphate permeases (genes SUL1 and SUL2).Rat sulphate anion transporter 1 (SAT-1).Mammalian DTDST, a probable sulphate transporter which, in human, is involved in the genetic disease, diastrophic dysplasia (DTD).Sulphate transporters 1, 2 and 3 from the legume Stylosanthes hamata.Human pendrin (gene PDS), which is involved in a number of hearing loss genetic diseases.Human protein DRA (Down-Regulated in Adenoma).Soybean early nodulin 70.Escherichia coli hypothetical protein ychM.Caenorhabditis elegans hypothetical protein F41D9.5.
The SLC26A/SulP family is a large and ubiquitous family with members derived from archaea, bacteria, fungi, plants and animals. Many organisms including Bacillus subtilis, Synechocystis sp, Saccharomyces cerevisiae, Arabidopsis thaliana and Caenorhabditis elegans possess multiple SulP family paralogues. Many of these proteins are functionally characterised, and most are inorganic anion uptake transporters or anion:anion exchange transporters. Some transport their substrate(s) with high affinities, while others transport it or them with relatively low affinities [
,
,
].SLC26A/SulP family proteins consist of N- and C- termini flanking a transmembrane domain thought to span the lipid bilayer 10-14 times. In most cases, the C-terminal cytoplasmic region includes a STAS (sulfate transporter and anti-sigma factor antagonist) domain [
].Malfunctions in members of the SLC26A family of anion transporters are involved in three human diseases: diastrophic dysplasia/achondrogenesis type 1B (DTDST), Pendred's syndrome (PDS) and congenital chloride diarrhoea (CLD). These proteins contain 12 transmembrane helices followed by a cytoplasmic STAS domain at the C terminus. The importance of the STAS domain in these transporters is illustrated by the fact that a number of mutations in PDS and DTDST map to it [
].Proteins in this family include:Neurospora crassa sulphate permease II (gene cys-14).Yeast sulphate permeases (SUL1 and SUL2).Rat sulphate anion transporter 1 (SAT-1).Mammalian DTDST, a probable sulphate transporter which, in human, is involved in the genetic disease, diastrophic dysplasia (DTD).Sulphate transporters 1, 2 and 3 from the legume Stylosanthes hamata.Human pendrin (gene PDS), which is involved in a number of hearing loss genetic diseases.Human protein DRA (Down-Regulated in Adenoma).Soybean early nodulin 70.Escherichia coli hypothetical protein YchM.Caenorhabditis elegans hypothetical protein F41D9.5.
