https://www.ncbi.nlm.nih.gov/Structure/pdb/1CG1
1CG1: STRUCTURE OF THE MUTANT (K16Q) OF ADENYLOSUCCINATE SYNTHETASE FROM E. COLI COMPLEXED WITH...
PROTEIN (ADENYLOSUCCINATE SYNTHETASE)6-O-PHOSPHORYL INOSINE MONOPHOSPHATEGUANOSINE-5'-DIPHOSPHATEHADACIDINMAGNESIUM ION