Corfe B M, Sammons R L, Smith D A, Mauël C
School of Biological Sciences, University of Birmingham, UK.
Microbiology (Reading). 1994 Mar;140 ( Pt 3):471-8. doi: 10.1099/00221287-140-3-471.
Spores of gerB spore germination mutants of Bacillus subtilis 168 are defective in response to the germinative mixture of L-asparagine, glucose, fructose and potassium ions (AGFK), but are normal in the L-alanine (ALA) triggered germination response. A lambda clone of 15 kbp carrying the gerB region has been identified. Sequencing of the gerB region of the clone revealed a cluster of three ORFs encoding putative proteins of 53.3, 41.3 and 42.4 kDa (GerBA, GerBB and GerBC, respectively). The first two of these proteins have substantial hydrophobic regions and the third is a possible lipoprotein. At least two, and probably all three products are required for normal germination in AGFK. The three proteins form a set of homologues of the products of the gerA operon, mutations in which cause a defect in the ALA germination pathway, but cause no defect in AGFK. The GerB proteins show 42%, 31% and 35% identity at the amino-acid level to the corresponding GerA proteins, and the homologues occur in the same order in both operons.
枯草芽孢杆菌168的gerB孢子萌发突变体的孢子对L-天冬酰胺、葡萄糖、果糖和钾离子（AGFK）的萌发混合物反应存在缺陷，但在L-丙氨酸（ALA）触发的萌发反应中正常。已鉴定出一个携带gerB区域的15kbp的λ克隆。对该克隆的gerB区域进行测序，发现了一个由三个开放阅读框组成的簇，分别编码推定的53.3kDa、41.3kDa和42.4kDa的蛋白质（分别为GerBA、GerBB和GerBC）。其中前两种蛋白质有大量疏水区域，第三种可能是脂蛋白。正常的AGFK萌发至少需要其中两种，可能三种产物都需要。这三种蛋白质形成了gerA操纵子产物的一组同源物，gerA操纵子的突变会导致ALA萌发途径出现缺陷，但在AGFK中无缺陷。GerB蛋白与相应的GerA蛋白在氨基酸水平上分别有42%、31%和35%的同一性，并且同源物在两个操纵子中的排列顺序相同。
