Cytochrome b6-f complex subunit 6 Cytochrome b6-f complex subunit PetL 31 Component of the cytochrome b6-f complex, which mediates electron transfer between photosystem II (PSII) and photosystem I (PSI), cyclic electron flow around PSI, and state transitions. PetL is important for photoautotrophic growth as well as for electron transfer efficiency and stability of the cytochrome b6-f complex (By similarity). Cytochrome b6-f complex subunit VI PETL_HORVU MLTLTSYFGFLLAALTITPALFIGLNKIRLI petL