ANALYSIS OF GENES ENCODING 2 UNIQUE TYPE IIA IMMUNOGLOBULIN G-BINDING PROTEINS EXPRESSED BY A SINGLE GROUP-A STREPTOCOCCAL ISOLATE
ANALYSIS OF GENES ENCODING 2 UNIQUE TYPE IIA IMMUNOGLOBULIN G-BINDING PROTEINS EXPRESSED BY A SINGLE GROUP-A STREPTOCOCCAL ISOLATE
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DOI：
10.1128/iai.62.4.1336-1347.1994
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发表时间：
1994-04-01
影响因子：
3.1
通讯作者：
PODBIELSKI, A
中科院分区：
文献类型：
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作者：
BOYLE, MDP;HAWLITZKY, J;PODBIELSKI, A
通过PCR扩增A群链球菌64/14株emm-like基因（emmL）和fcrA基因（emmL（64/14）和fcrA（64/14）），并强制克隆到热诱导表达载体pJLA 602中。emml基因编码以非免疫方式结合人IgG 1、IgG 2和IgG 4的重组蛋白。这是IIa型IgG结合蛋白的反应性特征。emmL（64/14）基因产物与先前鉴定的菌株-64/14的高分子量IIa型IgG结合蛋白抗原性相似，并且具有与野生型蛋白相同的N-末端序列。fcrA基因还编码具有IIa型功能活性的重组蛋白。该蛋白与先前从菌株64/14中分离的低分子量IIa型IgG结合蛋白相似，并且在抗原性上不同于由emmL（64/14）基因编码的高分子量IIa型蛋白。这两个基因的序列包括：间插区域。emmL基因表现出显着的同源性，其他I类emm和emmL基因表达的不透明因子阴性A组链球菌分离株。发现fcr A基因与通常存在于不透明因子阳性A组分离株中的其他fcr A基因同源。fcrA基因的上游序列和fcrA基因末端与emmL基因起始之间的插入序列与其他fcrA基因的报道相似。
An emm-like gene (emmL) and a fcrA gene from group A streptococcal strain 64/14 (emmL(64/14) and fcrA(64/14)) were amplified by PCR and force cloned into the heat-inducible expression vector pJLA 602. The emml gene encoded a recombinant protein that bound human IgG1, IgG2, and IgG4 in a nonimmune fashion. This is the reactivity profile of a type IIa IgG-binding protein. The emmL(64/14) gene product was antigenically similar to the previously identified high-molecular-weight type IIa IgG-binding protein of strain-64/14 and had an N-terminal sequence identical to that of the wild-type protein. The fcrA gene also encoded a recombinant protein with type IIa functional activity. This protein was similar to the lower-molecular-weight type IIa IgG-binding protein previously isolated from strain 64/14 and was antigenically distinct from the higher-molecular-weight type IIa protein encoded by the emmL(64/14) gene. The sequences for both genes including: the intervening regions are presented. The emmL gene demonstrates significant homology to other class I emm and emmL genes expressed by opacity factor-negative group A streptococcal isolates. The fcr A gene was found to be homologous to other fcrA genes normally present in opacity factor-positive group A isolates. The sequence upstream of the fcrA gene and the intervening sequence between the end of the fcrA gene and the start of the emmL gene were similar to those reported for other fcrA genes.