The genes encoding the transporters in the plant cell are grouped as the oligopeptide transporters and the yellow strip-like proteins. This multigene family encodes numerous types of substrates including glutathione, secondary amino acids adjoined with the metals, and small peptides, the metal homeostasis is attained through the functioning of the YSL transporters, which mediates the transportation of the metal-chelates. A level of conservation is identified in the biological function and substrates. The oligopeptide transporter is associated with functions such as the distant transportation of sulfur in the plants. The OPT proteins are also concerned with the functions such as metal homeostasis, nitrogen mobilization, and the sequestration of the heavy metal. The substances transported by the OPT proteins include peptides, metal-chelates, and glutathione.
Oligopeptide transporter Multigene Family:
The multigene family of oligopeptide transporter proteins is identified in the gram-positive bacteria gram-negative bacteria, archaea, yeast, plants, and animals. These proteins are grouped under a major facilitator super family. One of the important OPT proteins includes the proton-dependent oligopeptide transporters, which mediates the transportation of substances with the utilization of proton. The genes encoding these proteins are expressed upon the requirements for the need for the catalysis of the peptide transport. The members of the OPT family include the histidine transporters and nitrate permease. Certain members of the OPT family function in the transportation of the antibiotics. The proton symport mechanism is employed for the transport of the antibiotics.
The transport reaction carried out by the proteins encoded in the OPT multigene family involves the employment of a proton for the movement of a substrate in the cell. The proteins expressed by OPT multigene family have composed of 450 to 600 amino acyl residues. The eukaryotic transporters have a greater number of amino acids and are thus longer than the bacterial proteins. The transporters also have 12 putative trans membrane alpha-helical spanners. The transport of the substances is aided by the interaction taking place in the pairs of salt bridges positioned within the trans membrane helices. The members include hPEPT1-RF, FP12591, PTR4, SLC15A2, SLC15A1, PEPT1, SLC15A4, and SLC15A3. The subfamilies of the respective multigene family include oligopeptide transporter, peptide transporter, peptide: H+ symporter.
Yellow Stripe-Like Protein Multigene Family:
The yellow stripe-like proteins are employed for the transport of iron from the soil to all parts of the plant body. the family of yellow stripe-like proteins is based on the similarity identified with the yellow stripe 1 protein extracted from the maize. The complex formed from the association of phytosiderophores and yellow stripe 1 supports the transport of the iron in the plant body. The phytosiderophores are highly specific plant-derived iron chelators identified in the plants. The yellow stripe family is also identified in the non-grass species including the mosses, gymnosperms, dicots, and monocots. The metals associated with the nicotinamide are hypothesized to be transported by the yellow stripe-like transporters proteins in the non-grass species of plants. The nicotinamide is an iron chelator identified in all higher plants. The iron and copper chelated by nicotinamide are transported by the yellow strip-like 2 proteins and the gene of the respective protein is expressed in the shoots and the roots. The quantity of the copper and iron in the growth medium manages the expression of YSL2 proteins and the expression pattern aids in the lateral transportation of metal complexes.