NCCC[C@@H](CC(=O)N[C@@H]1CCNC[C@H]1C(=O)N[C@H](CC(=O)N[C@@H](CCC(=O)O)CC(=O)O)Cc1ccccc1)NC(=O)C[C@H](CO)NC(=O)[C@@H]1CCCC[C@H]1N
An acid's negative base-10 logarithmic dissociation constant (pka) follows directly from its underlying thermodynamics; pKa is directly proportional to its standard Gibbs free energy change. What is the pka value of this molecule?