Blanton K J, Biswas G D, Tsai J, Adams J, Dyer D W, Davis S M, Koch G G, Sen P K, Sparling P F
Department of Microbiology and Immunology, University of North Carolina, Chapel Hill 27599.
J Bacteriol. 1990 Sep;172(9):5225-35. doi: 10.1128/jb.172.9.5225-5235.1990.
Transferrin (TF) and lactoferrin (LF) are probably the major sources of iron (Fe) for Neisseria gonorrhoeae in vivo. We isolated mutants of N. gonorrhoeae FA19 that were unable to grow with Fe bound to either TF (TF-) or LF (LF-) or to both TF and LF ([TF LF]-). The amount of Fe internalized by each of the mutants was reduced to background levels from the relevant iron source(s). The wild-type parent strain exhibited saturable specific binding of TF and LF; receptor activity was induced by Fe starvation. The TF(-)-specific or LF(-)-specific mutants were almost completely lacking in receptor activity for TF or LF, respectively, whereas the [TF LF]- mutants bound both TF and LF as well as the wild-type strain. All mutants utilized citrate and heme normally as Fe sources. These results demonstrate that ability to bind TF or LF is essential for gonococci to scavenge appreciable amounts of Fe from these sources in vitro. In addition, the TF and LF Fe acquisition pathways are linked by the mutual use of a nonreceptor gene product that is essential to Fe scavenging from both of these sources; this gene product is not required for Fe acquisition from other sources.
转铁蛋白（TF）和乳铁蛋白（LF）可能是淋病奈瑟菌在体内铁（Fe）的主要来源。我们分离出了淋病奈瑟菌FA19的突变体，这些突变体无法在与TF（TF-）或LF（LF-）结合的铁或与TF和LF两者结合的铁（[TF LF]-）存在的情况下生长。每个突变体从相关铁源内化的铁量减少到背景水平。野生型亲本菌株表现出TF和LF的可饱和特异性结合；受体活性由铁饥饿诱导。TF（-）特异性或LF（-）特异性突变体分别几乎完全缺乏对TF或LF的受体活性，而[TF LF]-突变体与TF和LF的结合能力与野生型菌株相同。所有突变体都能正常利用柠檬酸盐和血红素作为铁源。这些结果表明，结合TF或LF的能力对于淋球菌在体外从这些来源摄取大量铁至关重要。此外，TF和LF的铁获取途径通过共同使用一种非受体基因产物而联系在一起，该基因产物对于从这两种来源清除铁是必不可少的；从其他来源获取铁则不需要这种基因产物。
