Genetic organization and locations of ttgABC and srpABC clusters. The ttgABC or srpABC genes are colored in the same pattern as for strain B6-2. The arrows indicate the size and direction of transcription of each gene. B6-2, P. putida B6-2; DOT-T1E, P. putida DOT-T1E (17, 19, 21); S12, P. putida S12 (15, 16, 28); VLB120, P. taiwanensis VLB120 (29); cLP6α, P. fluorescens cLP6α (22).