Molecular Cloning, Sequencing and N-Terminal Amino Acids Sequences Analysing of omega-gliadin from T. turgidum sp. paleocolchicum

摘要

In this study, we aim to get the DNA sequences of omega-gliadin gene from T. turgidum sp. paleocolchicum. Three wheat omega-gliadin gene sequences omega-gli-1, omega-gli-2 and omega-gli-3) were isolated from T. turgidum sp. paleocolchicum (2n = 4x = 28, AABB) using FCR primers, designed from published omega-gliadin gene sequences. omega-gli-3 could encode putative mature protein, while omega-gli-l and co-gli-2 were assumed to be pseudogenes due to their in-frame stop codon, which is attributed to thesingle base change C to T. The deduced omega-gliadin amino acid sequences were compared with all the omega-2 type omega-gliadins at GenBank. The omega-gliadin genes described here have a long repetitive domain with a repeat unit PFPQ_(1-2)PQQ, which isidentical with that proposed for 1 A, ID omega-gliadins, C-hordein and omega-secalin genes, but different from that proposed for IB omega-gliadins. These three omega-gliadin genes are of the ARQ-/ARE-variant type as categorized by the derived N-terminalamino-acid sequences and amino acid compositions. Based on the N-terminal protein sequences, co-gliadins could be divided into KEL, ARQ, ARE, XRQ, or RQ and SRL types, only the ARH-/ARQ-/ARE- and SLK-type o-gliadin were deduced from all the omega-gliadinDNA sequences at GenBank.