Identification and Characterizaation of Three GS Isoforms Essay

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3. Results
3.1. Identification and characterization of three GS isoforms
Three different GS sequences (GS01, GS02 and GS03) have been identified through the sequencing and blastx searching. All the sequences contain a complete coding sequence (CDS) region and 5′ and 3′-UTRs. In this study we have attempted the characterization of the multiple GS cDNAs present. The characteristics details of the full-length cDNAs of GS01 (Accession No. JQ740737), GS02 (Accession No. JQ740738) and GS03 (Accession No. JX457351) are given in Table 2.
Analysis with the UTRscan tool revealed the presence of one Musashi Binding Element (MBE) in both GS01 and GS02 transcripts. But there was no MBE present in GS03 UTR. Conserved Domain Database search (CD-search) …show more content…

NetPhos 2.0 analysis projected 9/11/11 serine, 2/3/2 threonine and 5/7/7 tyrosine phosphorylation sites for GS01/GS02/GS03 proteins respectively. The homology modelling of the enzyme shows 12 identical subunits, arranged in two layers of 6. The secondary structure of GS consisted of 7 alpha helix and 15 beta strands. The binding residues, predicted by the RaptorX binding web server, and the corresponding ligands for the three different GS proteins are given in Table 3.
3.3. Phylogenetic analysis
The alignment of the multiple GS amino acid sequences with fishes, amphibians and mammalian proteins is presented in Fig. . The homologous active site residues for GS in C. batrachus were determined using the Salmonella typhimurium GS X-ray crystallography structure (Gill and Eisenberg, 2001). The pairwise alignment shows presence of 15 of the 16 residues identified in Salmonella. The residues are completely conserved among fishes, amphibians and mammals (Fig.). With respect to the Salmonella, only three of 15 residues present in catfish are substituted (positions 194, 196 and 246). The phylogenetic tree clearly revealed
3.4. Differential expression of GS mRNA transcripts in NH4Cl-treated fish
There were significant increases of expression of different GS mRNA (GS01, GS02 and GS03) transcripts in different tissues (liver, kidney, brain and muscle) following the 50 mM NH4Cl treatment. In the brain, where

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