AAC
Home Help [Feedback] [For Subscribers] [Archive] [Search] [Contents]
This Article
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrowReprints and Permissions
Right arrow Copyright Information
Right arrow Books from ASM Press
Right arrow MicrobeWorld
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Ambúr, O.-H.
Right arrow Articles by Arias, C. A.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Ambúr, O.-H.
Right arrow Articles by Arias, C. A.

 Previous Article  |  Next Article 

Antimicrobial Agents and Chemotherapy, January 2002, p. 95-100, Vol. 46, No. 1
0066-4804/01/$04.00+0     DOI: 10.1128/AAC.46.1.95-100.2002
Copyright © 2002, American Society for Microbiology. All Rights Reserved.

D-Ala:D-Ala Ligase Gene Flanking the vanC Cluster: Evidence for Presence of Three Ligase Genes in Vancomycin-Resistant Enterococcus gallinarum BM4174

Ole-Herman Ambúr,1 Peter E. Reynolds,1 and Cesar A. Arias1,2*

Department of Biochemistry, University of Cambridge, Cambridge, United Kingdom,1 Bacterial Molecular Genetics Unit, Centro de Investigaciones, Universidad El Bosque, Bogotá, Colombia2

Received 16 May 2001/ Returned for modification 2 August 2001/ Accepted 1 October 2001

An open reading frame located 230 nucleotides downstream from the stop codon of vanSc and in the opposite direction relative to the other genes of the vanC cluster was identified in Enterococcus gallinarum BM4174. This gene (designated ddl2) encoded a protein of 343 amino acids that had significant predicted structural similarity to D-Ala:D-Ala ligases and displayed 33 and 35% amino acid identity to VanC-1 and the previously reported partial sequence of Ddl from E. gallinarum, respectively. Biochemical characterization by thin-layer chromatography confirmed that Ddl2 is a D-Ala:D-Ala ligase with no detectable D-Ala:D-Ser ligase activity. The vancomycin dependence of Enterococcus faecalis BM4320 (ddl mutant) was lost on electroporation of a plasmid construct expressing ddl2 constitutively. The latter strain was able to grow in the absence of vancomycin, and peptidoglycan precursor analysis under the same conditions indicated the synthesis of pentapeptide[D-Ala] as the main precursor, confirming the activity of Ddl2 in vivo. Expression of ddl and ddl2 in BM4174 was tested by reverse transcription-PCR: results suggested that both D-Ala:D-Ala ligases were expressed concomitantly. Our findings indicate that vancomycin-resistant E. gallinarum BM4174 is likely to express one D-Ala:D-Ser and two D-Ala:D-Ala ligase genes.

* Corresponding author. Mailing address: Bacterial Molecular Genetics Unit, Universidad El Bosque, Transv 9a Bis No. 133-25, Bogotá, Colombia. Phone: (571) 523-4879. Fax: (571) 216-5116. E-mail: caa22{at}cable.net.co.

Antimicrobial Agents and Chemotherapy, January 2002, p. 95-100, Vol. 46, No. 1
0066-4804/01/$04.00+0     DOI: 10.1128/AAC.46.1.95-100.2002
Copyright © 2002, American Society for Microbiology. All Rights Reserved.



This article has been cited by other articles:



Home Help [Feedback] [For Subscribers] [Archive] [Search] [Contents]
Clin. Vaccine Immunol. Clin. Microbiol. Rev.
J. Clin. Microbiol. ALL ASM JOURNALS

Copyright © 2002 by the American Society for Microbiology. All rights reserved.