5-amino-1-(5-phospho-D-ribosyl)imidazole-4-carboxylate + ATP + L-aspartate = (2S)-2-[5-amino-1-(5-phospho-beta-D-ribosyl)imidazole-4-carboxamido]succinate + ADP + 2 H(+) + phosphate 5-amino-1-(5-phospho-D-ribosyl)imidazole-4-carboxylate + H(+) = 5-amino-1-(5-phospho-beta-D-ribosyl)imidazole + CO2 Purine metabolism; IMP biosynthesis via de novo pathway; 5-amino-1-(5-phospho-D-ribosyl)imidazole-4-carboxamide from 5-amino-1-(5-phospho-D-ribosyl)imidazole-4-carboxylate: step 1/2. Purine metabolism; IMP biosynthesis via de novo pathway; 5-amino-1-(5-phospho-D-ribosyl)imidazole-4-carboxylate from 5-amino-1-(5-phospho-D-ribosyl)imidazole (carboxylase route): step 1/1. Homooctamer. In the N-terminal section; belongs to the SAICAR synthetase family. In the C-terminal section; belongs to the AIR carboxylase family. Class II subfamily.