The effects of methionine acquisition and synthesis on Streptococcus pneumoniae growth and virulence.
The effects of methionine acquisition and synthesis on Streptococcus pneumoniae growth and virulence.
复制标题
DOI：
10.1371/journal.pone.0049638
复制
发表时间：
2013
期刊：
影响因子：
3.7
通讯作者：
Brown JS
中科院分区：
文献类型：
--
作者：
Basavanna S;Chimalapati S;Maqbool A;Rubbo B;Yuste J;Wilson RJ;Hosie A;Ogunniyi AD;Paton JC;Thomas G;Brown JS
细菌病原体需要从宿主获取营养，但对于许多营养物质在感染过程中的重要性仍知之甚少。我们使用影响假定的甲硫氨酸 ABC 转运脂蛋白（Sp_0149、metQ）和/或甲硫氨酸生物合成酶（Sp_0585 - Sp_0586、metE 和 metF）的基因删除菌株，研究了甲硫氨酸获取和合成对肺炎链球菌生长和毒力的重要性。免疫印迹分析证实 MetQ 是一种脂蛋白，存在于所有研究的肺炎链球菌菌株中。然而，尽管刺激了强烈的特异性 IgG 反应，但 MetQ 疫苗接种并不能预防小鼠致命的肺炎链球菌感染。色氨酸荧光光谱和等温滴定量热法表明，MetQ 对 L-蛋氨酸具有高亲和力和特异性，KD 约为 25 nM，并且 ΔmetQ 菌株对 C14-蛋氨酸的摄取减少。 ΔmetQ/ΔmetEF菌株的生长在含有低浓度甲硫氨酸的化学成分确定的培养基和血液中受到极大损害，但通过添加高浓度的外源甲硫氨酸部分恢复。混合感染模型显示ΔmetQ、ΔmetEF和ΔmetQ/ΔmetEF菌株在小鼠鼻咽部定植的能力没有减弱。在全身感染的小鼠模型中，尽管所有小鼠均出现显着感染，但与野生型菌株相比，ΔmetQ/ΔmetEF菌株感染后脾脏细菌CFU降低。这些数据表明 Sp_0149 编码高亲和力甲硫氨酸 ABC 转运脂蛋白，并且 Sp_0585 – Sp_0586 可能是甲硫氨酸合成所必需的。尽管 Sp_0149 和 Sp_0585-Sp_0586 对完全毒力做出了贡献，但两者对于肺炎链球菌在感染期间的存活都不是必需的。
Bacterial pathogens need to acquire nutrients from the host, but for many nutrients their importance during infection remain poorly understood. We have investigated the importance of methionine acquisition and synthesis for Streptococcus pneumoniae growth and virulence using strains with gene deletions affecting a putative methionine ABC transporter lipoprotein (Sp_0149, metQ) and/or methionine biosynthesis enzymes (Sp_0585 - Sp_0586, metE and metF). Immunoblot analysis confirmed MetQ was a lipoprotein and present in all S. pneumoniae strains investigated. However, vaccination with MetQ did not prevent fatal S. pneumoniae infection in mice despite stimulating a strong specific IgG response. Tryptophan fluorescence spectroscopy and isothermal titration calorimetry demonstrated that MetQ has both a high affinity and specificity for L-methionine with a KD of ∼25 nM, and a ΔmetQ strain had reduced uptake of C14-methionine. Growth of the ΔmetQ/ΔmetEF strain was greatly impaired in chemically defined medium containing low concentrations of methionine and in blood but was partially restored by addition of high concentrations of exogenous methionine. Mixed infection models showed no attenuation of the ΔmetQ, ΔmetEF and ΔmetQ/ΔmetEF strains in their ability to colonise the mouse nasopharnyx. In a mouse model of systemic infection although significant infection was established in all mice, there were reduced spleen bacterial CFU after infection with the ΔmetQ/ΔmetEF strain compared to the wild-type strain. These data demonstrate that Sp_0149 encodes a high affinity methionine ABC transporter lipoprotein and that Sp_0585 – Sp_0586 are likely to be required for methionine synthesis. Although Sp_0149 and Sp_0585-Sp_0586 make a contribution towards full virulence, neither was essential for S. pneumoniae survival during infection.
登录
查看更多内容
影响因子：
4.4
作者：
Bryan, Joshua D.;Liles, Roxanne;Shelver, Daniel
通讯作者：
Shelver, Daniel
影响因子：
3.2
作者：
Merlin, C;Gardiner, G;Masters, M
通讯作者：
Masters, M
影响因子：
3.6
作者：
Brown, JS;Gilliland, SM;Holden, DW
通讯作者：
Holden, DW
影响因子：
3.1
作者：
Brown, JS;Ogunniyi, AD;Paton, JC
通讯作者：
Paton, JC
影响因子：
3
作者：
Himpsl, Stephanie D.;Lockatell, C. Virginia;Mobley, Harry L. T.
通讯作者：
Mobley, Harry L. T.