Sakamoto K, Margolles A, van Veen H W, Konings W N
Brewing Research & Development Laboratory, Asahi Breweries, Ltd., Moriya-machi, Kitasoma-gun, Ibaraki 302-0106, Japan.
J Bacteriol. 2001 Sep;183(18):5371-5. doi: 10.1128/JB.183.18.5371-5375.2001.
Lactobacillus brevis is a major contaminant of spoiled beer. The organism can grow in beer in spite of the presence of antibacterial hop compounds that give the beer a bitter taste. The hop resistance in L. brevis is, at least in part, dependent on the expression of the horA gene. The deduced amino acid sequence of HorA is 53% identical to that of LmrA, an ATP-binding cassette multidrug transporter in Lactococcus lactis. To study the role of HorA in hop resistance, HorA was functionally expressed in L. lactis as a hexa-histidine-tagged protein using the nisin-controlled gene expression system. HorA expression increased the resistance of L. lactis to hop compounds and cytotoxic drugs. Drug transport studies with L. lactis cells and membrane vesicles and with proteoliposomes containing purified HorA protein identified HorA as a new member of the ABC family of multidrug transporters.
短乳杆菌是变质啤酒的主要污染物。尽管啤酒中存在赋予其苦味的抗菌啤酒花化合物,但该微生物仍能在啤酒中生长。短乳杆菌对啤酒花的抗性至少部分取决于horA基因的表达。HorA推导的氨基酸序列与乳酸乳球菌中的一种ATP结合盒式多药转运蛋白LmrA的序列有53%的同一性。为了研究HorA在啤酒花抗性中的作用,利用乳链菌肽控制的基因表达系统,在乳酸乳球菌中功能性表达了带有六组氨酸标签的HorA蛋白。HorA的表达增加了乳酸乳球菌对啤酒花化合物和细胞毒性药物的抗性。对乳酸乳球菌细胞、膜囊泡以及含有纯化HorA蛋白的蛋白脂质体进行的药物转运研究表明,HorA是ABC多药转运蛋白家族的一个新成员。