Dicker I B, Seetharam S
Du Pont Co., Wilmington, Delaware 19880-0328.
J Bacteriol. 1991 Jan;173(1):334-44. doi: 10.1128/jb.173.1.334-344.1991.
The Escherichia coli gene firA, previously reported to code for a small, histonelike DNA-binding protein, has been cloned and found to reside immediately downstream from skp, a gene previously identified as the firA locus. firA encodes a 36-kDa protein. The mutant firA200(Ts) allele was also cloned and shown to contain three mutations, each mutation giving rise to a single amino acid change. Partially purified wild-type FirA (from a firA+ strain) and mutant FirA [from a firA200(Ts) strain] proteins have amino-terminal sequences predicted from their common DNA sequences. Both proteins lack an N-terminal methionine. Modest overexpression of wild-type or mutant FirA restored wild-type growth to firA200(Ts) strains at 43 degrees C, whereas high-level expression of wild-type FirA was required for more complete suppression of the rifampin sensitivity of firA200(Ts) rpoB double mutants. High-level expression of mutant FirA did not suppress this rifampin sensitivity.
大肠杆菌基因firA，先前报道其编码一种小的、类组蛋白的DNA结合蛋白，已被克隆，并发现它位于skp基因的紧下游，skp基因先前被确定为firA基因座。firA编码一种36 kDa的蛋白质。突变的firA200(Ts)等位基因也被克隆，并显示含有三个突变，每个突变导致一个氨基酸变化。部分纯化的野生型FirA（来自firA+菌株）和突变型FirA[来自firA200(Ts)菌株]蛋白具有从其共同DNA序列预测的氨基末端序列。两种蛋白质都缺乏N末端甲硫氨酸。野生型或突变型FirA的适度过表达在43℃时使firA200(Ts)菌株恢复野生型生长，而野生型FirA的高水平表达是更完全抑制firA200(Ts) rpoB双突变体对利福平敏感性所必需的。突变型FirA的高水平表达并未抑制这种利福平敏感性。
