Required for the insertion of some light-harvesting complexes (LHC) proteins into the chloroplast thylakoid membrane. Essential for the assembly and activity of LHC I and II. Its function is probably partly distinct from that of ALB3.2. Associates with the LHCII complex and with the psaE subunit of the LHCI complex. Belongs to the OXA1/ALB3/YidC (TC 2.A.9.2) family.