Software to create nucleotids - (Feb/03/2015 )

Could anz one of zou provide me with a link or software to create a nucleotides or a miRNA sequence in graph   ? 

I am not sure I understand what exactly you are looking for. Can you elaborate?

I wanted to create a cover letter for a good paper and I am working on miRNAs. So, I wanted to create a figure with some small RNAs so I think I need a software of online tool to create this. Or do you have another idea. 

Thanks 

I've drawn complete structures of 25-base oligos using ChemDraw.  It probably presents far more structural detail than you want, but once you have drawn the four base residues they are fairly easy to assemble into a sequence with cut & paste.