aeq::G5A is a bioluminescent Ca[2+] reporter. It is a fusion protein composed of a modified green fluorescent protein, a 5 residue linker sequence and the Avic\aeq protein. The green fluorescent protein is based on EGFP, with an additional V163A substitution to improve protein folding and increase the fluorescence at 37[o]C (PMID:10860991).