Preparation and characterization of Neisseria meningitidis mutants deficient in production of the human lactoferrin-binding proteins LbpA and LbpB
Preparation and characterization of Neisseria meningitidis mutants deficient in production of the human lactoferrin-binding proteins LbpA and LbpB
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DOI：
10.1128/jb.180.12.3080-3090.1998
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发表时间：
1998-06-01
影响因子：
3.2
通讯作者：
Schryvers, AB
中科院分区：
文献类型：
--
作者：
Bonnah, RA;Schryvers, AB
奈瑟氏球菌科的致病成员产生特异性受体，促进从其哺乳动物宿主的转铁蛋白（TF）和乳铁蛋白（Lf）获得铁。转铁蛋白受体由两种外膜蛋白组成，即转铁蛋白结合蛋白A和B（TbpA和Tbp B;以前分别命名为Tbp 1和Tbp 2）。虽然以前只认识到一种单一的LF结合蛋白LbpA（以前称为Lbp 1），但我们最近通过改良的亲和分离技术在人类病原体脑膜炎奈瑟氏菌和卡他莫拉氏菌以及牛病原体莫拉氏菌中鉴定了其他细菌LF结合蛋白（R. A.邦纳河H. Yu和A. B。Schryvers，Microb.帕托格19：285-297，1995），在这份报告中，我们描述了位于N.脑膜炎B16 B6 lbpA基因。各种TbpB与来自上游ORF的翻译DNA序列的产物的氨基酸序列比较表明，该区域编码LF结合蛋白B同源物（Lbp B）。来自菌株B16 B6的LbpB具有两个大的带负电荷的氨基酸段，其不存在于各种转铁蛋白受体同源物（TbpB）中。与麦芽糖结合蛋白融合的重组LbpB蛋白的表达证明了功能性LF结合活性。对脑膜炎球菌等基因突变体的研究表明，LbpA基因和紧邻lbpA上游的tale ORF（推定的lbpB基因）被插入失活，LbpA而不是LbpB是体外从Ef获得铁所必需的。
Pathogenic members of the family Neisseriaceae produce specific receptors facilitating iron acquisition from transferrin (TF) and lactoferrin (Lf) of their mammalian host. Tf receptors are composed of two outer membrane proteins, Tf-binding proteins A and B (TbpA and TbpB; formerly designated Tbp1 and Tbp2, respectively). Although only a single Lf-binding protein, LbpA (formerly designated Lbp1), had previously been recognized, we recently identified additional bacterial Lf-binding proteins in the human pathogens Neisseria in meningitidis and Moraxella catarrhalis and the bovine pathogen Moraxella bovis by a modified affinity isolation technique (R. A. Bonnah, R.-H. Yu, and A. B. Schryvers, Microb. Pathog. 19:285-297, 1995), In this report, we characterize an opera reading frame (ORF) located immediately upstream of the N. meningitidis B16B6 lbpA gene. Amino acid sequence comparisons of various TbpBs with the product of the translated DNA sequence from the upstream ORF suggests that the region encodes the Lf-binding protein B homolog (LbpB). The LbpB from strain B16B6 has two large stretches of negatively charged amino acids that are not present in the various transferrin receptor homologs (TbpBs). Expression of the recombinant LbpB protein as a fusion with maltose binding protein demonstrated functional Lf-binding activity, Studies with Ri meningitidis isogenic mutants in which the lbpA gene and tale ORF immediately upstream of lbpA (putative lbpB gene) were insertionally inactivated demonstrated that LbpA, but not LbpB, is essential for iron acquisition from Ef in vitro.