Molecular basis of intercellular adhesion in the biofilm-forming Staphylococcus epidermidis
Molecular basis of intercellular adhesion in the biofilm-forming Staphylococcus epidermidis
复制标题
DOI：
10.1111/j.1365-2958.1996.tb02548.x
复制
发表时间：
1996-06-01
影响因子：
3.6
通讯作者：
Gotz, F
中科院分区：
文献类型：
--
作者：
Heilmann, C;Schweitzer, O;Gotz, F
表皮葡萄球菌基因icaABC参与了多糖细胞间粘附素（PIA）的合成，PIA特异性抗血清的免疫荧光研究表明，PIA主要位于细胞表面。PIA是一种由至少130个2-脱氧-2-氨基-d -葡萄糖吡喃基残基组成的线性-1,6链葡萄糖氨基聚糖，其中80-85%为n-乙酰化，其余为非n-乙酰化且带正电荷。icaABC基因簇（ica，细胞间粘附）中的转座子插入导致一些性状的丧失，如在聚苯乙烯表面形成生物膜的能力、细胞聚集和PIA的产生。该突变体可以通过转化携带icaABC的质粒pCN27来补充。pCN27转移到异源宿主肉葡萄球菌中，导致大细胞聚集体的形成，玻璃表面生物膜的形成，以及PIA的表达。icaABC的核苷酸序列表明，这三个基因被组织在一个操纵子中，它们是由icaA启动子共转录而来，icaA包含四个潜在的跨膜螺旋，表明其位于膜上。最明显的是与一种参与脂质生物合成的根瘤菌（Rhizobium meliloti）的n -乙酰氨基葡萄糖转移酶（22.5%的总体一致性和37.4%的总体相似性），这种相似性表明IcaA在形成-1,6链n -乙酰- d -氨基葡萄糖基聚合物中具有n -乙酰氨基葡萄糖转移酶活性。IcaB分泌到培养基中，含有一种典型的信号肽。廉政公署是疏水性的，包含六个预测的跨膜螺旋分布在其整个长度，典型的整体膜蛋白。IcaB和IcaC都与已知蛋白没有相似之处，它们的功能也是未知的。pCN27中icaA、icaB或icaC的失活导致葡萄细胞间粘附表型的完全丧失，这表明这三个基因都参与细胞间粘附、PIA表达和易位。
The Staphylococcus epidermidis genes icaABC are involved in the synthesis of the polysaccharide intercellular adhesin (PIA), which is located mainly on the cell surface, as shown by immunofluorescence studies with PIA-specific antiserum. PIA was shown to be a linear beta-1,6-linked glucosaminoglycan composed of at least 130 2-deoxy-2-amino-D-glucopyranosyl residues of which 80-85% are N-acetylated, the rest being non-N-acetylated and positively charged. A transposon insertion in the icaABC gene cluster (ica, intercellular adhesion) led to the loss of several traits, such as the ability to form a biofilm on a polystyrene surface, cell aggregation, and PIA production, The mutant could be complemented by transformation with the icaABC-carrying plasmid pCN27. Transfer of pCN27 into the heterologous host Staphylococcus carnosus led to the formation of large cell aggregates, the formation of a biofilm on a glass surface, and PIA expression. The nucleotide sequence of icaABC suggests that the three genes are organized in an operon and that they are co-transcribed from the mapped icaA promoter, IcaA contains four potential transmembrane helices, indicative of a membrane location, The deduced IcaA sequence shows similarity to those of polysaccharide-polymerizing enzymes, the most pronounced being with a Rhizobium meliloti N-acetylglucosaminyltransferase involved in lipo-chitin biosynthesis (22.5% overall identity and 37.4% overall similarity), This similarity suggests that IcaA has N-acetylglucosaminyltransferase activity in the formation of the beta-1,6-linked N-acetyl-D-glucosaminyl polymer. IcaB is secreted into the medium and contains a typical signal peptide. IcaC is hydrophobic and contains six predicted transmembrane helices distributed over its entire length, typical for an integral membrane protein. Neither IcaB nor IcaC shares similarity with known proteins, and their function is unknown. Inactivation of icaA, icaB, or icaC in pCN27 led to the complete loss of the intercellular adhesion phenotype in S. carnosus, suggesting that all three genes are involved in intercellular adhesion, PIA expression, and translocation.