a nudix hydrolase active on dinucleoside 5'-polyphosphates associated with invasion of human erythrocytes by Bartonella bacilliformis; ialA = Invasion-Associated Locus; nudix hydrolases = nucleoside diphosphates linked to another moiety (X); hydrolyzes Ap4A, Ap5A, Ap6A, Gp4G and Gp5G; amino acid sequence in first source; GenBank L25276