Pneumococcal pili are composed of protofilaments exposing adhesive clusters of Rrg A.
Pneumococcal pili are composed of protofilaments exposing adhesive clusters of Rrg A.
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DOI：
10.1371/journal.ppat.1000026
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发表时间：
2008-03-21
期刊：
影响因子：
6.7
通讯作者：
Ferlenghi I
中科院分区：
文献类型：
--
作者：
Hilleringmann M;Giusti F;Baudner BC;Masignani V;Covacci A;Rappuoli R;Barocchi MA;Ferlenghi I
肺炎链球菌是世界范围内致病和死亡的主要原因，已在其细胞表面发现了菌毛。与革兰氏阴性菌相比，人们对革兰氏阳性菌中天然菌毛的结构及其在致病性中的作用知之甚少。细长结构的三重免疫电子显微镜显示，纯化的菌毛主要含有RRGB，其次是聚集的RrgA和单个的RrgC分子。金颗粒的排列显示抗RRGB抗体沿整个菌毛均匀分布，形成主干结构。抗RrgA抗体沿丝呈2-3个单位的颗粒聚集体，通常与单个RrgC亚基共存。用低温电子显微镜和冷冻干燥/金属阴影技术获得的数据分析表明，菌毛是由至少两个原丝排列成卷曲的、不同直径的致密超结构形成的寡聚体附属物。在酶联免疫吸附试验中使用细胞外基质蛋白，辅助RrgA被鉴定为菌毛的主要粘附素。结合结构和功能数据，出现了一个模型，其中毛状RRGB主干作为RRgA表面定位的粘附簇的载体，从而促进与宿主的相互作用。肺炎链球菌是人类最重要的病原体之一，也是世界范围内发病率和死亡率的主要原因，可引起呼吸道感染、社区获得性肺炎和侵袭性疾病。虽然肺炎球菌是一种研究得很好的细菌病原体，最早在19世纪末被描述，但它表面的菌毛是最近才发现的。菌毛是从细菌表面伸出的细长结构，是革兰氏阳性和革兰氏阴性细菌的重要毒力因子。细菌菌毛被认为参与了细菌对宿主的黏附，这是细菌感染的关键步骤。与革兰氏阴性菌毛相比，人们对天然革兰氏阳性菌毛的结构知之甚少。本研究以天然纯化的致病性肺炎球菌TIGR4菌毛为材料，主要利用低温电子显微镜技术对其结构组成进行了研究。菌毛由原丝组成，这些原丝排列成盘绕的、紧密的、不同直径的超结构。菌毛表面辅助蛋白RrgA与选定的细胞外基质化合物的粘附性可能是菌毛介导的宿主-病原体相互作用的一部分。对本地肺炎球菌菌毛的分析揭示了革兰氏阳性菌毛的结构基础，这也可以作为有效疫苗设计的基础。
Pili have been identified on the cell surface of Streptococcus pneumoniae, a major cause of morbidity and mortality worldwide. In contrast to Gram-negative bacteria, little is known about the structure of native pili in Gram-positive species and their role in pathogenicity. Triple immunoelectron microscopy of the elongated structure showed that purified pili contained RrgB as the major compound, followed by clustered RrgA and individual RrgC molecules on the pilus surface. The arrangement of gold particles displayed a uniform distribution of anti-RrgB antibodies along the whole pilus, forming a backbone structure. Antibodies against RrgA were found along the filament as particulate aggregates of 2–3 units, often co-localised with single RrgC subunits. Structural analysis using cryo electron microscopy and data obtained from freeze drying/metal shadowing technique showed that pili are oligomeric appendages formed by at least two protofilaments arranged in a coiled-coil, compact superstructure of various diameters. Using extracellular matrix proteins in an enzyme-linked immunosorbent assay, ancillary RrgA was identified as the major adhesin of the pilus. Combining the structural and functional data, a model emerges where the pilus RrgB backbone serves as a carrier for surface located adhesive clusters of RrgA that facilitates the interaction with the host. Streptococcus pneumoniae (pneumococcus) is one of the most important human pathogens and a major cause of morbidity and mortality worldwide, causing respiratory tract infections, community acquired pneumonia, and invasive diseases. Although the pneumococcus is a well-studied bacterial pathogen, first described in the late 19th century, pili on its surface were discovered only recently. Pili are elongated structures extruding from the bacterial surface and were found to be important virulence factors of both Gram-positive and Gram-negative bacteria. Bacterial pili are considered to participate in bacterial adhesion to a host, a crucial step in bacterial infection. In contrast to Gram-negative pili, little is known about the structure of native Gram-positive pili. We used native purified pili of pathogenic pneumococcus TIGR4 to study its structural composition, mainly by the use of cryo EM techniques. Pili were found to be composed of protofilaments that are arranged in a coiled-coil, compact superstructure of various diameters. Adhesive properties of pilus surface located ancillary protein RrgA to selected compounds of the extracellular matrix might be part of the pilus mediated host–pathogen interplay. Analysis of native pneumococcal pili revealed structural basics of a Gram-positive pilus that could also serve as a basis for effective vaccine design.
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影响因子：
3.6
作者：
Hung, TT;Marraffini, LA;Schneewind, O
通讯作者：
Schneewind, O
DOI：
10.1073/pnas.0511017103
发表时间：
2006-02-21
影响因子：
11.1
作者：
Barocchi, MA;Rie, J;Henriques-Normark, B
通讯作者：
Henriques-Normark, B
影响因子：
3.2
作者：
Mu, XQ;Egelman, EH;Bullitt, E
通讯作者：
Bullitt, E
影响因子：
3.6
作者：
Middleton, AM;Chadwick, MV;Wilson, R
通讯作者：
Wilson, R
影响因子：
3.6
作者：
Nelson AL;Ries J;Bagnoli F;Dahlberg S;Fälker S;Rounioja S;Tschöp J;Morfeldt E;Ferlenghi I;Hilleringmann M;Holden DW;Rappuoli R;Normark S;Barocchi MA;Henriques-Normark B
通讯作者：
Henriques-Normark B