Expression of ZAT12 transcripts in transgenic tomato under various abiotic stresses and modeling of ZAT12 protein in silico.

ZAT12 a C2H2-zinc-finger protein is an abiotic stress-responsive transcription factor in plants having less information about their structure. Transcription analysis proved that ZAT12 transcripts over-expressed during drought, heat and salt stress conditions which led to an interest in 3-D structural studies of ZAT12in Brassica carinata. Over-expression of BcZAT12 in transformed tomato plants under abiotic stresses, suggest role of ZAT12 in conferring stress-tolerance in tomato. Sequence analysis of ZAT12 protein (Accession No. ABB55254.1) from B. carinata revealed it as a 161 amino acid long protein with short conserved motif (140)LDLXL(144) in C-terminal, a leucine rich L-Box with-(14)EXXAXCLXXL(23) motif in N-terminal region and presence of two conserved Zinc-Finger motifs "CXXCXXXXXXXQALGGHXXXH" between positions 42-62 and 85-105. The two zinc finger motifs have presence of two conserved glutamic acid (Glu) and phenylalanine (Phe) residues. Two methionine (Met) residues at position 94 and 102 present in ZF-motif-2 were absent in ZF-motif-1. The (94)Met and (97)Ala in ZF-motif-2 were found to be replaced by serine (Ser) in ZF-motif-1. Homology and ab initio structural modeling of ZAT12 encoded BcZAT12 protein of B. carinata resulted in robust 3-D models and were evaluated for structural motifs, associated GO terms and protein-DNA interactions. The BcZAT12 protein model, was of good quality, reliable, stable and is deposited in PMDB database (PMDB ID: PM0078213). BcZAT12 is annotated as an intracellular protein having molecular function in Zn-binding which in turn regulates signal transduction/translation processes in response to abiotic stresses in plants. Results suggest BcZAT12 protein to interact directly with one strand of dsDNA via electrostatic and H-bonds.