Table 2. Available Level 2 vectors.

Level 1 modules used for assembly	Corresponding Level 2 vectors (HR1/HR2)	Auxotrophic markers for selection
A, B	pL2_AB_hc/pl2_AB_lc (A0_C0)	URA3, LEU2
A, B, C	pL2_AC_hc/pL2_AC_lc (A0_D0)	URA3, LEU2, HIS3
A, B, C, D	pL2_AD_hc/pL2_AD_lc (A0_E0)	URA3, LEU2, HIS3, LYS2
A, B, C, D, E	pL2_AE_hc/pl2_AE_lc (A0_F0)	URA3, LEU2, HIS3, LYS2, TRP1

Depending on the number of Level 1 modules to assemble, different Level 2 vectors must be used. Each vector is available in high- and low-copy format (hc/lc). Depending on the assembled Level 1 modules, the resulting Level 2 construct can be selected with up to five auxotrophic markers.