Catalyzes the transfer of a geranyl-geranyl moiety from geranyl-geranyl pyrophosphate to proteins having the C-terminal C-A-A-L where A is an aliphatic amino acid (PubMed:8262067, PubMed:9781874). In particular it modifies the GTP-binding component of the 1,3-beta-D-glucan synthase (PubMed:8262067). geranylgeranyl diphosphate + L-cysteinyl-[protein] = diphosphate + S-geranylgeranyl-L-cysteinyl-[protein] Binds 1 zinc ion per subunit. Heterodimer of an alpha(cwp1) and a beta(cwg2) subunit. Belongs to the protein prenyltransferase subunit beta family.