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Wang C,
Hayes B,
Vestling MM,
Takayama K,
( 2006 ) Transposome mutagenesis of an integral membrane transporter in Corynebacterium matruchotii. PMID : 16403458 : DOI : 10.1016/j.bbrc.2005.12.097 Abstract >>
A transposon-5 insertion library of Corynebacterium matruchotii ATCC14266 was generated and screened for mutants with altered corynomycolic acid content. One of these designated 319 mutants showed an interruption of a gene encoding an integral membrane protein. MALDI mass spectra of trehalose monocorynomycolate (TMCM), trehalose dicorynomycolate, and methyl corynomycolates derived from cell wall arabinogalactan-corynomycolate showed that these lipids from the mutant contained a lower amount of short-chain (C24 to C34) and much greater amount of long-chain (primarily C(36:2)) corynomycolic acids than the wild type. An analysis of mRNA demonstrated that the integral membrane protein and ATP-binding cassette transporter are transcriptionally coupled. These results suggested that the proteins/enzymes encoded by the membrane transporter gene locus preferably move short-chain corynomycolic acids from the cytoplasm across the membrane bilayer to the periplasmic space where the synthesis of TMCM is thought to occur. This is the first evidence linking corynomycolic acid to a transporter gene locus.
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2. |
Khamis A,
Raoult D,
La Scola B,
( 2004 ) rpoB gene sequencing for identification of Corynebacterium species. PMID : 15364970 : DOI : 10.1128/JCM.42.9.3925-3931.2004 PMC : PMC516356 Abstract >>
The genus Corynebacterium is a heterogeneous group of species comprising human and animal pathogens and environmental bacteria. It is defined on the basis of several phenotypic characters and the results of DNA-DNA relatedness and, more recently, 16S rRNA gene sequencing. However, the 16S rRNA gene is not polymorphic enough to ensure reliable phylogenetic studies and needs to be completely sequenced for accurate identification. The almost complete rpoB sequences of 56 Corynebacterium species were determined by both PCR and genome walking methods. In all cases the percent similarities between different species were lower than those observed by 16S rRNA gene sequencing, even for those species with degrees of high similarity. Several clusters supported by high bootstrap values were identified. In order to propose a method for strain identification which does not require sequencing of the complete rpoB sequence (approximately 3,500 bp), we identified an area with a high degree of polymorphism, bordered by conserved sequences that can be used as universal primers for PCR amplification and sequencing. The sequence of this fragment (434 to 452 bp) allows accurate species identification and may be used in the future for routine sequence-based identification of Corynebacterium species.
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