Competence and virulence of Streptococcus pneumoniae: Adc and PsaA mutants exhibit a requirement for Zn and Mn resulting from inactivation of putative ABC metal permeases
Competence and virulence of Streptococcus pneumoniae: Adc and PsaA mutants exhibit a requirement for Zn and Mn resulting from inactivation of putative ABC metal permeases
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DOI：
10.1046/j.1365-2958.1997.5111879.x
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发表时间：
1997-08-01
影响因子：
3.6
通讯作者：
Claverys, JP
中科院分区：
文献类型：
--
作者：
Dintilhac, A;Alloing, G;Claverys, JP
在寻找转化缺陷突变体的过程中，鉴定了肺炎链球菌（一种重要的人类病原体）的adcCBA推定操纵子。发现AdcA与编码链球菌粘附素的ATP结合盒（ABC）转运操纵子具有同源性，如副血链球菌的FimA和肺炎链球菌的PsaA，后者最近被证明是通过小鼠鼻内或腹腔内攻击判断毒力所必需的。定义了一个新的金属特异性外部溶质结合蛋白家族，在这项工作中，北方分析揭示了存在两个起源于adcC或更上游的adcB-adcA特异性转录物，这与ade是操纵子的假设一致，对ade和psaA突变体在合成培养基中生长的研究表明，添加Zn提高了前者的生长速率，而后者表现出对添加的Mn的绝对需求，除非以适当的比例添加两种金属，否则psaA-Bu双突变体被证明基本上是不能存活的。总之，这些结果表明以前没有记载的S。添加Zn也恢复了ade突变体细胞在标准转化培养基中的接近正常的自发转化。发现Zn在细胞与感受态刺激肽接触后不久就被特异性地需要，揭示了在肺炎链球菌转化中对Zn的意外需要。从标准转化培养基中去除Mn也导致psaA突变细胞的转化缺陷。两者合计，这些结果使我们提出，Adc是ABC型锌通透酶，第一个这样的蛋白质复合物中确定的任何生物体，和Psa ia的ABC型锰通透酶复合物。
The adcCBA putative operon of Streptococcus pneumoniae, an important human pathogen, was identified in a search for transformation-deficient mutants. It was found to exhibit homology to ATP-binding cassette (ABC) transport operons encoding streptococcal adhesins such as FimA of Streptococcus parasanguis and PsaA of S, pneumoniae, The latter was recently shown to be essential for virulence as judged by intranasal or intraperitoneal challenge of mice, We suggested previously that AdcA, together with a set of 14 proteins, including PsaA and homologous adhesins, defines a new family of external solute-binding proteins specific for metals, In this work, Northern analysis revealed the existence of two adcB-adcA specific transcripts originating within adcC or further upstream, consistent with the hypothesis that ade is an operon, Investigation of growth of ade and psaA mutants in synthetic medium revealed that the addition of Zn improved the growth rate of the former, whereas the latter exhibited an absolute requirement for added Mn, A psaA-adc double mutant turned out to be essentially non-viable unless both metals were added in the appropriate ratio. Taken together, these results suggest a previously undocumented requirement of S. pneumoniae for Zn and Mn, The addition of Zn also restored near-normal spontaneous transformation of ade mutant cells in standard transformation medium. Zn was found to be specifically required soon after contact of cells with the competence-stimulating peptide, revealing an unsuspected need for Zn in transformation of S, pneumoniae, The removal of Mn from standard transformation medium also resulted in transformation deficiency of psaA mutant cells. Taken together, these results lead us to propose that Adc is an ABC-type Zn permease, the first such protein complex identified in any organism, and that Psa ia an ABC-type Mn permease complex.