RESIDUE 2KT 13 CONECT C4 4 C3 H41 H42 H43 CONECT C3 4 C4 C2 H31 H32 CONECT C2 3 C3 O3 C CONECT O3 1 C2 CONECT C 3 C2 OXT O CONECT OXT 2 C HXT CONECT O 1 C CONECT H41 1 C4 CONECT H42 1 C4 CONECT H43 1 C4 CONECT H31 1 C3 CONECT H32 1 C3 CONECT HXT 1 OXT END HET 2KT 13 HETSYN 2KT 2-OXOBUTANOIC ACID HETNAM 2KT 2-KETOBUTYRIC ACID FORMUL 2KT C4 H6 O3