Aminocarboxypropyltransferase that catalyzes the aminocarboxypropyl transfer on pseudouridine at position 1191 (Psi1191) in 18S rRNA (PubMed:27084949). It constitutes the last step in biosynthesis of the hypermodified N1-methyl-N3-(3-amino-3-carboxypropyl) pseudouridine (m1acp3-Psi) conserved in eukaryotic 18S rRNA (PubMed:27084949). Required for processing 35S pre-rRNA at site D (PubMed:19806183). N(1)-methylpseudouridine(1191) in yeast 18S rRNA + S-adenosyl-L-methionine = H(+) + N(1)-methyl-N(3)-[(3S)-3-amino-3-carboxypropyl]pseudouridine(1191) in yeast 18S rRNA + S-methyl-5'-thioadenosine Minor growth defect caused by late 18S rRNA processing defects, leading to a ribosomal subunit imbalance with a reduced 40S to 60S ratio. Present with 3610 molecules/cell in log phase SD medium. Belongs to the TDD superfamily. TSR3 family.