RESIDUE   AST      4
CONECT      AS     3 O1   O2   O3  
CONECT      O1     1 AS  
CONECT      O2     1 AS  
CONECT      O3     1 AS  
END   
HET    AST              4
HETNAM     AST ARSENITE
FORMUL      AST    As1 O3 3-