Binding and accumulation of hemin in Neisseria gonorrhoeae.
Binding and accumulation of hemin in Neisseria gonorrhoeae.
复制标题
淋病奈瑟菌中血红素的结合和积累。
DOI：
10.1128/iai.63.12.4634-4641.1995
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发表时间：
1995
影响因子：
3.1
通讯作者：
Genco,CA
中科院分区：
文献类型：
--
作者：
Desai,PJ;Nzeribe,R;Genco,CA
利用氯化高铁血红素和含氯化高铁血红素的化合物用于营养铁（Fe）摄取的能力已被记录用于几种病原菌。淋病奈瑟菌可以利用游离氯化血红素作为生长的铁源，然而，有关氯化血红素运输的机制知之甚少。在这项研究中，我们的特点是结合和积累氯化血红素的N。淋病，并确定了淋球菌氯化血红素受体的特异性。n.淋病F62在含有铁螯合剂Desferal的化学成分确定的培养基中生长，通过加入[59 Fe]氯化血红素（4.0或8.0 μ M;比活度，7.0 Ci/mol）启动氯化血红素转运。N.淋病是能量依赖性的，并且59 Fe显示在对数生长期间以恒定速率在细胞中积累。然而，我们观察到的放射性标记的氯化血红素时，无机铁存在于生长培养基中的59铁的摄取减少。从放射性标记的氯化血红素的59 Fe的结合被抑制，除了冷氯化血红素，血卟啉，或血红蛋白，但不是由柠檬酸铁。虽然[14C]氯化血红素被发现支持N.淋病，我们没有检测到从放射性标记的氯化血红素的14C的摄取。淋球菌周质铁结合蛋白（Fbp）的提取培养物与[59 Fe]氯化血红素表明，大部分的59 Fe与Fbp。两者合计，这里提出的结果表明，氯化血红素结合到淋球菌外膜受体通过分子的原卟啉部分，并在结合后，铁被除去并转运到细胞中，在那里它是与淋球菌周质铁结合蛋白，Fbp。
The ability to utilize hemin and hemin-containing compounds for nutritional iron (Fe) uptake has been documented for several pathogenic bacteria. Neisseria gonorrhoeae can utilize free hemin as a source of Fe for growth; however, little is known concerning the mechanisms involved in hemin transport. In this study we have characterized the binding and accumulation of hemin by N. gonorrhoeae and defined the specificity of the gonococcal hemin receptor. N. gonorrhoeae F62 was grown in a chemically defined medium containing the iron chelator Desferal, and hemin transport was initiated by the addition of [59Fe]hemin (4.0 or 8.0 microM; specific activity, 7.0 Ci/mol). 59Fe uptake from radiolabeled hemin by N. gonorrhoeae was energy dependent, and 59Fe was shown to accumulate in the cell at a constant rate during logarithmic growth. However, we observed a decrease in the uptake of 59Fe from radiolabeled hemin when inorganic iron was present in the growth medium. Binding of 59Fe from radiolabeled hemin was inhibited by the addition of either cold hemin, hematoporphyrin, or hemoglobin, but not by ferric citrate. Although [14C]hemin was found to support the growth of N. gonorrhoeae, we did not detect the uptake of 14C from radiolabeled hemin. Extraction of the gonococcal periplasmic ferric binding protein (Fbp) from cultures grown with [59Fe]hemin indicated that a majority of the 59Fe was associated with the Fbp. Taken together, the results presented here indicate that hemin binds to a gonococcal outer membrane receptor through the protoporphyrin portion of the molecule and that following binding, iron is removed and transported into the cell, where it is associated with the gonococcal periplasmic ferric binding protein, Fbp.