The lumQ gene is linked to the lumP gene and the lux operon in Photobacterium leiognathi

Abstract

The nucleotide sequence of the designated lumQ gene (EMBL accession No. U35231) from Photobacterium leiognathi PL741 has been determined, and the encoded amino acid sequence is deduced. The LumQ protein has a calculated M(r) of 28,416 and comprises 248 amino acid residues. The lumQ gene is identified as the envY-like gene by significant similarity of the encoded protein with the EnvY and AdiY proteins of E. coli; there the envY gene encodes the porin thermoregulatory protein EnvY, and the adiY gene encodes the putative transcriptional regulator protein AdiY. It suggests that the lumQ gene of P. leiognathi is orthologous to the envY and adiY genes of E. coli. The function of the protein encoded by the lumQ gene from P. leiognathi is not really defined yet, it is likely to be the DNA-binding protein related to the araC and xylS family of transcriptional regulators. The lumQ and lumP genes form the lum operon which linked to the lux operon, but run in the opposite direction. The gene order of the lum and the lux operon is < -ter-lumQ-lumP-R&R-luxC-luxD-luxA-luxB- luxN-luxE- > (R&R: regulatory region; ter: transcriptional terminator); whereas the regulatory region (R&R) includes two promoter systems, PR-promoter for the lux operon and PL-promoter for the lum operon; ter is the transcriptional terminator of the lum operon.