RESIDUE   U9S     13
CONECT      C02    3 C04  O01  O03 
CONECT      C04    4 C02  C05  O09  H1  
CONECT      C05    4 C04  C06  O09  H2  
CONECT      C06    3 C05  O07  O08 
CONECT      O01    1 C02 
CONECT      O03    2 C02  H3  
CONECT      O07    1 C06 
CONECT      O08    2 C06  H4  
CONECT      O09    2 C04  C05 
CONECT      H1     1 C04 
CONECT      H2     1 C05 
CONECT      H3     1 O03 
CONECT      H4     1 O08 
END   
HET    U9S             13
HETSYN     U9S cis-2,3-epoxysuccinic acid
HETNAM     U9S (2R,3S)-oxirane-2,3-dicarboxylic acid
FORMUL      U9S    C4 H4 O5