RESIDUE   X1S     15
CONECT      CB     4 CG   S    HB1C HB2C
CONECT      CG     4 CB   CD   HG1C HG2C
CONECT      CD     3 CG   OE1  OE2 
CONECT      OE1    1 CD  
CONECT      OE2    2 CD   HE2 
CONECT      O1     2 S    H1  
CONECT      O2     1 S   
CONECT      O3     1 S   
CONECT      S      4 CB   O1   O2   O3  
CONECT      HB1C   1 CB  
CONECT      HB2C   1 CB  
CONECT      HG1C   1 CG  
CONECT      HG2C   1 CG  
CONECT      HE2    1 OE2 
CONECT      H1     1 O1  
END   
HET    X1S             15
HETNAM     X1S 3-SULFOPROPANOIC ACID
FORMUL      X1S    C3 H6 O5 S1