COc1ccc2[nH]cc(CCNC(=O)[C@](O)(Cc3cn(C)c4ccccc34)[C@@]3(O)OCC(O)C3O)c2c1
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?