Involved in one of the last steps of the biosynthesis of chlorophyll a. Catalyzes the esterification of chlorophillide a with either geranylgeranyldiphosphate (GGPP) or phytyldiphosphate (PhyPP). May also use with a lower efficiency the monophosphates GGMP and PhyMP, but not the non-phosphorylated alcohols geranylgeraniol and phytol. The tetraprenyl diphosphate must bind to the enzyme as the first substrate and esterification occurs when this pre-loaded enzyme meets the second substrate, chlorophyllide. chlorophyllide a + H(+) + phytyl diphosphate = chlorophyll a + diphosphate Magnesium or zinc; or manganese at a lesser extent, but not calcium. Inhibited by N-phenylmaleimide (NPM) and diacetyl. Constitutively expressed in etiolated and green seedlings. The N-terminal part (1-87) is not required for enzymatic activity. Amino acid residues 138-160 are probably part of the polyprenyl diphosphate-binding domain. Belongs to the UbiA prenyltransferase family. Chlorophyll synthase subfamily.