Covalent structure of subunits of bacterial luciferase: NH2-terminal sequence demonstrates subunit homology.

Abstract

The heterodimeric subunit structure of bacterial luciferase was demonstrated more than 10 yr ago. The enzymes from Beneckea harveyi and Photobacterium fischeri [Vibrio fischeri] were since studied in detail; they each consist of 2 nonidentical subunits, designated .alpha. and .beta.. Both are required for bioluminescence activity, with the active center apparently confined to the .alpha. subunit. Amino acid sequence analysis of the NH2 termini of the .alpha. and .beta. subunits of the B. harveyi and P. fischeri luciferases not only confirms the earlier observation that the .alpha. subunits are homologous but also demonstrates that the NH2-terminal sequences of the .beta. subunits of the luciferases from the 2 genera are homologous. Within each luciferase, the NH2-terminal sequences of the .alpha. and .beta. subunits are similar, suggesting the possibility that the genes coding for .alpha. and .beta. may have arisen by gene duplication, presumably prior to divergence of the lines leading to present-day luminous bacteria.