Miyamoto K, Nakahigashi K, Nishimura K, Inokuchi H
Department of Biophysics, Faculty of Science, Kyoto University, Japan.
J Mol Biol. 1991 Jun 5;219(3):393-8. doi: 10.1016/0022-2836(91)90180-e.
Six mutants of Escherichia coli K12 that are sensitive to visible light have been isolated. Five of them, including an amber mutant, are defective in a gene that maps near 11 minutes on the linkage map of the chromosome, and this gene has been designated visA. The sixth mutant, which was isolated from bacteria that carried the visA+/visA+ diploid allele, is defective in a gene that maps near 63 minutes on the linkage map, which has been designated visB. These mutant strains of bacteria are killed by illumination with visible light. The effective wavelength of the light is around 460 nm. The nucleotide sequence of the visA gene was determined. As a result of a search for homologous products, we found that visA may be identical to hemH, the structural gene for ferrochelatase which catalyzes a final step in the biosynthesis of heme. A possible mechanism for the killing of the visA mutant bacteria is discussed.
已分离出6株对可见光敏感的大肠杆菌K12突变体。其中5株，包括1株琥珀突变体，在染色体连锁图上位于约11分钟处的一个基因有缺陷，该基因被命名为visA。从携带visA+/visA+二倍体等位基因的细菌中分离出的第6个突变体，在连锁图上位于约63分钟处的一个基因有缺陷，该基因被命名为visB。这些细菌突变株经可见光照射后会死亡。光的有效波长约为460纳米。测定了visA基因的核苷酸序列。通过搜索同源产物，我们发现visA可能与hemH相同，hemH是催化血红素生物合成最后一步的铁螯合酶的结构基因。讨论了visA突变细菌致死的可能机制。
