I need a link to an online tool where I can upload small peptide sequences or FASTA format proteins that do not necessarily have a PDB accession. Any idea?
I dont think there is any tool which can get Ramachandran plot from the sequences, you can model the sequence and then upload it in SAVES, PDBsum or RAMPHAGE server to get the plot. As 3D structure of the protein is more valuable and important in determining the functioning of protein than sequence you should model your protein first than analyse its plot. Hope this helps.