Abstract
Defensins are cysteine-rich small proteins found in plants and animals. Esr-6 (embryo surrounding region-6), which is a kind of plant defensin gene, plays an important role in nutrition, defense, and signaling of embryo. In this study, Esr-6 genes in three Turkish maize varieties (TMVs) such as Safak, Sakarya, and Seker were sequenced and characterized. Open reading frame (ORF) and protein length of Esr-6 was found as 324 bp and 111 amino acids, respectively. All TMVs contained gamma-thionin family (PF00304) domain, and subcellular localizations were predicted as extracellular. Predicted signal peptide, mature protein, and acidic pro-domain were identified in all TMVs. Four most conserved motifs were identified, but only motif 1 was found to be related with gamma-thionin family. Eight conserved cysteine residues, which are the characteristics of defensins, were detected in all TMVs. In phylogenetic analysis, Esr-6 proteins were clearly diverged from other plant defensins with the highest bootstrap value (100 %). Predicted 3D structures of Esr-6 proteins were similar to each other, including one a-helix and two beta-sheets. Conserved cysteine residues, including Cys51, Cys55, Cys66, Cys73, Cys75, and Cys79, were detected in 3D structures of all TMVs. Our study showed that Esr-6 genes and their product are well conserved among TMVs.