Puroindoline genes are highly conserved in diploid ancestor wheats and related species but absent in tetraploid Triticum species
ABSTRACT Using a PCR approach, we showed that puroindoline genes are present in diploid and hexaploid Triticum species but absent in tetraploid species, and that T. tauschii is likely to be the donor of the T. aestivum puroindoline genes. Puroindoline-like genes are present in cereals closely related to wheat (barley, oat and rye) and absent in cereals more distantly related to wheat (maize, rice and sorghum). Barley, oat and rye puroindoline-like sequences and primary structure of deduced proteins are highly conserved. In oat, avenoindolines are more closely related to puroindolines than to tryptophanins.
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ABSTRACT: A number of protein sequences deduced from the molecular analysis of plant cDNA or genomic libraries can be grouped in relation to a defined number of cysteine residues located in distinct positions of their sequences. This is the case for a group of around 500 polypeptides from different species that contain a small domain (less than 100 amino acids residues) displaying a pattern of eight-cysteines in a specific order. The plant sequences containing this motif belong to proteins having different functions, ranging from storage, protection, enzyme inhibition and lipid transfer, to cell wall structure. The eight-cysteine motif (8CM) appears to be a structural scaffold of conserved helical regions connected by variable loops, as observed by three-dimensional structure analysis. It is proposed that the cysteine residues would form a network of disulfide bridges necessary, for the maintenance of the tertiary structure of the molecule together with the central helical core, while the variable loops would provide the sequences required for the specific functions of the proteins.Plant Physiology and Biochemistry 06/2004; 42(5):355-65. · 2.84 Impact Factor