Bioinformatic and empirical analysis of a gene encoding serine/threonine protein kinase regulated in response to chemical and biological fertilizers in two maize (Zea mays L.) cultivars

Molecular structure of a gene, ZmSTPK1, encoding a serine/threonine protein kinase in maize was analyzed by bioinformatic tool and its expression pattern was studied under chemical biological fertilizers. Bioinformatic analysis cleared that ZmSTPK1 is located on chromosome 10, from position 141015332 to 141017582. The full genomic sequence of the gene is 2251 bp in length and includes 2 exons. Its cDNA length is 1900 bp with a 5'-untranslated region of 311 bp and 3'-untranslated region of 341 bp, of which 1248 bp from open reading frame encoding 415 amino acid residues with a molecular weight of 46 kDa and an isoelectric point 7.2. Also, an upstream open reading frame contains 100 aa was found at -12 position from ATG initiation codon. ZmSTPK1 with a long half-life, 10 hours in Escherichia coli, and instability index of 32.25 is classified as a stable protein. A calmodulin binding domain was found in ZmSTPK1 at position from 395 to 405 in C-terminal end. The helical wheel analysis showed that the stretch of residues Ile-395 to Asp-415 has the potential to form a charged amphiphilic -helix characteristic of a calmodulin-binding region. Two P1BS-like motifs, which are present in the promoter regions of Pi starvation-induced genes, were located at positions -48 and -867 from ATG initiation codon. The expression of ZmSTPK1 responded to available phosphate, and its expression up-regulated under phosphate starvation.