Lin J W, Chao Y F, Weng S F
Institute of Molecular Biology, National Chung Hsing University, Taiwan, Republic of China.
Biochem Biophys Res Commun. 1998 May 19;246(2):446-52. doi: 10.1006/bbrc.1998.8641.
Nucleotide sequence of the luxG gene (GenBank Accession No. AF053227) from Photobacterium leiognathi PL741 has been determined, and the encoded probable flavin reductase is deduced. The probable flavin reductase encoded by the luxG gene has a calculated M(r) 26,544 and comprises 235 amino acid residues. The probable flavin reductase like the NAD(P)H-flavin reductase might catalyze the reduction of flavins. Alignment and comparison of the probable flavin reductases from P. leiognathi PL741, ATCC 25521, P. phosphoreum, Vibrio fischeri, and V. harveyi show that they are homologous; there is 66% homologous (29.4% identity and 36.6% similarity). Also, the probable flavin reductase is homologous to the NAD(P)H-flavin reductase; it is perceived that the probable flavin reductase and the NAD(P)H-flavin reductase could be enzyme isoforms encoded by two genes of a multigene family for differential response functions. Functional analysis illustrates that the specific segment sequence lay inside and behind the luxG gene might form the potential hairpin loops omega gI, omega gII, omega o, and omega oT as mRNA stability loop or/and as the attenuator-like loop or the dynamic terminator-like block for sub-regulation in the lux operon. The gene order of the luxG gene in the lux operon and the lum operon is <--ter-lumQ-lumP-R&R-luxC-luxD-luxA-luxB-+ ++luxN-luxE-luxG--> (R&R: regulatory region; ter: transcriptional terminator), whereas the R&R is the regulatory region for the lum operon and the lux operon, and ter is the transcriptional terminator for the lum operon.
已确定来自吕宋发光杆菌PL741的luxG基因（GenBank登录号AF053227）的核苷酸序列，并推导了其编码的可能的黄素还原酶。luxG基因编码的可能的黄素还原酶计算分子量为26,544，由235个氨基酸残基组成。该可能的黄素还原酶可能像NAD(P)H-黄素还原酶一样催化黄素的还原。对来自吕宋发光杆菌PL741、ATCC 25521、磷光杆菌、费氏弧菌和哈氏弧菌的可能的黄素还原酶进行比对和比较，结果表明它们是同源的；同源性为66%（同一性为29.4%，相似性为36.6%）。此外，该可能的黄素还原酶与NAD(P)H-黄素还原酶同源；据推测，该可能的黄素还原酶和NAD(P)H-黄素还原酶可能是多基因家族中两个基因编码的酶同工型，具有不同的响应功能。功能分析表明，luxG基因内部和后面的特定片段序列可能形成潜在的发夹环ωgI、ωgII、ωo和ωoT，作为mRNA稳定性环或/和作为衰减子样环或动态终止子样阻断，用于lux操纵子中的亚调控。luxG基因在lux操纵子和lum操纵子中的基因顺序为<--ter-lumQ-lumP-R&R-luxC-luxD-luxA-luxB-+ ++luxN-luxE-luxG-->（R&R：调控区；ter：转录终止子），而R&R是lum操纵子和lux操纵子的调控区，ter是lum操纵子的转录终止子。
