O=C(O)CC[C@@H](C(=O)O)N1C(=O)[C@H]2[C@@H]3CC[C@H](C3)[C@H]2C1=O
The donor in a hydrogen bond is usually a strongly electronegative atom such as N, O, or F that is covalently bonded to a hydrogen bond. How many hydrogen bond donors does the molecule have?