A schematic model of cyanobacterial NDH-1 complex assembly. NdhH, NdhJ, NdhK, and NdhM are first assembled to form a 100-kD complex. Meanwhile, NdhI, as well as unknown factors, are assembled to form the 130- kD complex and the 300-kD complex. Subsequently, NdhN, NdhO, and NdhI are assembled to form the NDH-1M complex. The basic complex NDH-1M is combined with specific domains to assemble the functional complexes NDH-1L, NDH-1MS, and NDH-1MS′.