The name/synonym for ligand GBL (curated from ChEBI, PubChem, and PDB databases):

1GAMMA-BUTYROLACTONE
2BUTYROLACTONE
34-BUTYROLACTONE
4DIHYDRO-2(3H)-FURANONE
51,4-BUTANOLIDE
64-HYDROXYBUTYRIC ACID LACTONE
7GAMMA-HYDROXYBUTYROLACTONE
84-DEOXYTETRONIC ACID
9DIHYDROFURAN-2(3H)-ONE
101,2-BUTANOLIDE
11GAMMA-HYDROXYBUTYRIC ACID LACTONE
12GAMMA-BUTANOLACTONE