Comparison of the lipoprotein gene among the enterobacteriaceae. DNA sequence of Morganella morganii lipoprotein gene and its expression in Escherichia coli.

Y X Huang,G Ching,M Inouye

doi:10.1016/s0021-9258(20)82039-0

Abstract

A DNA sequence of 532 base pairs encompassing the entire Morganella morganii lipoprotein gene (lpp) was determined. Sequence comparisons of the M. morganii lpp gene with the lpp genes from Escherichia coli, Serratia marcescens, and Erwinia amylovora reveal that the M. morganii lpp gene is more distantly related to the E. coli lpp gene than any of the other lpp genes examined. Between the E. coli and M. morganii lpp genes, the following homologies were found: 44% in the promoter region (bases, -45 to -1), 88% in the 5'-end untranslated region of the mRNA, 58% in the signal sequence coding region, 75% in the coding region for the first 51 and 43% for the last 7 amino acid residues. Upstream of the promoter region and downstream of the termination codon, there are extensive insertions, deletions, and base substitutions. In spite of the differences in the DNA sequences, the lipoprotein structure was found to be highly conserved except for the carboxyl-terminal sequence of 7 amino residues. The coding region of the M. morganii lpp gene including the signal sequence was inserted into an expression cloning vector so that the production of the M. morganii lipoprotein could be induced in E. coli by a lac inducer, isopropyl-beta-D-thioglactoside. It was found that when induced, the M. morganii prolipoprotein was apparently secreted normally across the E. coli cytoplasmic membrane, modified with glycerol and palmitic acid, processed to the mature lipoprotein, and assembled in the E. coli outer membrane. The bound form covalently linked to the peptidoglycan was also found.

Highlights

A DNA sequence of 532 base pairs encompassing the and Proteus morganii ( Morganella morganii [3])
Between the E. coli and M. morganii lpp related to E . coli among those bacteria listed above, it is of genes, the following homologies were found: 44% in great interest tcolone their Ipp genes and to characterize their the promoter region,88% in the5’
We found a restriction enzyme that producedasingle specific DNA restriction fragment from M. morganii DNA that hybridized to a probe derived from the S. marcescens 1pp gene

Summary

Comparison of the Lipoprotein Gene among the Enterobacteriaceae

DNA SEQUENCE OF MORGANELLA MORGANZZ LIPOPROTEIN GENEAND ITS EXPRESSION INESCHERZCHIA COLI*. We undertook to identify and isolate a DNA fragment from the M. morganii chromosomal DNA which carries the lpp gene. For this purpose, we found a restriction enzyme that producedasingle specific DNA restriction fragment from M. morganii DNA that hybridized to a probe derived from the S. marcescens 1pp gene. We found a restriction enzyme that producedasingle specific DNA restriction fragment from M. morganii DNA that hybridized to a probe derived from the S. marcescens 1pp gene Using this restriction fragment,we were able toclone the M. structure was found to behighly conserved except for morganii lpp gene and to determine its DNA sequence. We have characterized the a lac inducer, isopropyl-&D-thioglactoside It was M. morganii lipoprotein produced in E. coli cells.

Thelipoproteinis a major outermembraneproteinin

RESULTS

DISCUSSION

Findings

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