Truncation of Vargula luciferase still results in retention of luminescence

Significant amino acid sequence homology in two regions of Vargula hilgendorfii to one in apoaequorin was reported. The intra-amino acid homology in Vargula luciferase between residues 81-312 and 321-540 was 19.3%, and each of this intra-homologous region contained the region homologous to apoaequorin. In order to prove the possibility that only one of the homologous regions is sufficient for luminescence, we have produced a chimeric protein comprising of only the N-terminal homologous region of Vargula luciferase fused to protein A. Comparison of the luminescence of this truncate luciferase indicated that there was 38.5% retention in the bioluminescence of luciferase when compared to that of the mature form of luciferase. This fact may have interesting implications for further study of engineering luciferase.