Unusual absence of head-to-tail chains in the crystal structure of glycyl-L-glutamyl-L-phosphoseryl-L-leucine

Abstract

The structure of glycyl-L-glutamyl-L-phosphoseryl- L-leucine, (C 16H 29N 4O 11P) 2· 3H 2Ois reported. The dimeric structure is characterized by an unusual absence of head-to-tail chains in connection with an extended intermolecular hydrogen bonding network. Two of the three H 2O molecules included in the network are disordered. The protonation constants of the tetrapeptide were determined as log K 1 = 1.50, log K 2 = 3.63, log K 3 = 4.32, log K 4 = 6.08 and log K 5 = 8.65 by potentiometric pH titration. © Springer Science+Business Media, LLC 2012.