Hi everyone, recently I have been trying to conjugate the RGD peptides onto my nanoparticle in order to target the intergrin. But when I was to use EDC/NHS to react with the N terminal of the RGD, I am not sure whether to buy GGGRGD or GGGDGR (G is my N terminal and would react with COOH -containing ligands already  bound to my NPs) Should I buy GGGRGD or the other instead?

Thanks for answering.

P.S the GGG sequence acts as spacer.