Involved in the biosynthesis of the phytotoxin coronatine (COR). Catalyzes the transfer of the aminoacyl group covalently attached to the pantetheinyl arm of CmaA to the holo-pantetheinyl arm of CmaD. During the shuttling process, CmaE generates a covalent-aminoacyl-S-Cys enzyme intermediate by the action of its donor substrate L-aminoacyl-S-CmaA and delivers it to the sulfhydryl group attached to the phosphopantetheinyl arm on CmaD. holo-[CmaD peptidyl-carrier protein] + L-alloisoleucyl-[CmaA peptidyl-carrier protein] = holo-[CmaA peptidyl-carrier protein] + L-alloisoleucyl-[CmaD peptidyl-carrier protein] In vitro, is able to accept L-Phe as a substrate when presented on CmaD and is able to load this aminoacyl moiety onto heterologous T domains. Thus, CmaE should be useful for shuttling different aminoacyl groups between T domains existing within heterologous nonribosomal peptide-synthetase (NRPS) assembly lines to generate natural product-like derivatives. Belongs to the AB hydrolase superfamily.