GENOMIC ORGANIZATION OF THE KLEBSIELLA-PNEUMONIAE CPS REGION RESPONSIBLE FOR SEROTYPE K2 CAPSULAR POLYSACCHARIDE SYNTHESIS IN THE VIRULENT-STRAIN CHEDID
GENOMIC ORGANIZATION OF THE KLEBSIELLA-PNEUMONIAE CPS REGION RESPONSIBLE FOR SEROTYPE K2 CAPSULAR POLYSACCHARIDE SYNTHESIS IN THE VIRULENT-STRAIN CHEDID
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DOI：
10.1128/jb.177.7.1788-1796.1995
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发表时间：
1995-04-01
影响因子：
3.2
通讯作者：
OHTA, M
中科院分区：
文献类型：
--
作者：
ARAKAWA, Y;WACHAROTAYANKUN, R;OHTA, M
研究了肺炎克雷伯菌基因组中负责衣壳多糖合成的cps区(O1：K2)的基因组结构。缺失分析和Southern杂交研究表明，克隆的29khBamHI片段的中心区是K2被膜多糖合成所必需的。测定了克雷伯氏菌cps区24,329个核苷酸序列，并通过DDBJ数据库和GenBank数据库进行了存储，登录号为D21242。仅在测序区中就发现了19个可能的开放阅读框(ORF)。其中，13个ORF距离非常近。19个ORF中有6个分别与鼠伤寒沙门氏菌CPSG、cpsB、rfbP和orf2.8、大肠杆菌GND和流感嗜血杆菌bexD具有较高的核苷酸序列相似性。此外，ORF10产物的氨基酸序列具有高度的疏水性，与普氏立克次体ATP/ADP转位酶具有相似的膜拓扑结构。与o(54)依赖启动子类似的核苷酸序列，以及通常的-35和-10序列，仅在ORF3的上游发现，ORF3是多顺反子结构中的第一个ORF。此外，在o(54)依赖的启动子类似序列的下游发现的一个序列(GGGCGGTAGCGT)在与细胞表面多糖合成有关的基因簇中通常是保守的，如沙门氏菌RFB和VIAB以及大肠杆菌kpsMT和rfaQPG。在ORF15下游发现了一个可能的具有发夹环结构的转录终止子，它是E.ColiGND的同源物。在大肠杆菌K-12中，K2壳多糖的生物合成依赖于cpsB(甘露糖-1-磷酸鸟苷转移酶基因)，而位于多顺反子结构下游的克雷伯氏菌cpsB能够补充cpsB。线圈。转座子插入和启动子克隆分析结果与核苷酸序列分析结果一致。
The genomic organization of the chromosomal cps region that is responsible for capsular polysaccharide synthesis in Klebsiella pneumoniae Chedid (O1:K2) was investigated. Deletion analyses and Southern hybridization studies suggested that the central region of the cloned 29-kh BamHI fragment is indispensable for K2 capsular polysaccharide synthesis. The 24,329-bp nucleotide sequence of the Klebsiella cps region was determined and deposited in the EMBL and GenBank databases through DDBJ and assigned accession number D21242. Nineteen possible open reading frames (ORFs) mere identified in the sequenced area. Among them, 13 ORFs are very close to each other. Six of the 19 ORFs show considerable nucleotide sequence similarities to Salmonella typhimurium cpsG, cpsB, rfbP, and orf2.8, Escherichia coli gnd, and Haemophilus influenzae bexD, respectively. Moreover, the deduced amino acid sequence of the ORF10 product demonstrated a highly hydrophobic profile and showed putative membrane topology similarity to Rickettsia prowazekii ATP/ADP translocase. Nucleotide sequences similar to the o(54)-dependent promoter, as well as the usual -35 and -10 sequences, mere identified just upstream of ORF3, which is the first ORF in the polycistronic structure. Furthermore, a sequence (GGGCGGTAGCGT) found just downstream of the o(54)-dependent promoter-like sequence was generally conserved among gene clusters implicated in cell surface polysaccharide synthesis, such as Salmonella rfb and viaB and E. coli kpsMT and rfaQPG. A possible transcriptional terminator with a hairpin loop structure found just downstream of ORF15 that is a homolog of E. coli gnd. K2 capsular polysaccharide biosynthesis in E. coli K-12 depends on cpsB (mannose-1-phosphate guanyltransferase gene), and klebsiella cpsB, found in the downstream region of the polycistronic structure, was able to complement cpsB off. coil. Results of transposon insertion and promoter-cloning analyses were consistent with the results of nucleotide sequence analysis.