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 Hujer, A. M.
Right arrow Articles by Bonomo, R. A.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Hujer, A. M.
Right arrow Articles by Bonomo, R. A.

 Previous Article  |  Next Article 

Antimicrobial Agents and Chemotherapy, February 2005, p. 612-618, Vol. 49, No. 2
0066-4804/05/$08.00+0     doi:10.1128/AAC.49.2.612-618.2005
Copyright © 2005, American Society for Microbiology. All Rights Reserved.

Structure-Activity Relationships of Different ß-Lactam Antibiotics against a Soluble Form of Enterococcus faecium PBP5, a Type II Bacterial Transpeptidase

Andrea M. Hujer,1 Malgosia Kania,2 Thomas Gerken,3 Vernon E. Anderson,3 John D. Buynak,4 Xiaoxia Ge,4 Patrick Caspers,2 Malcolm G. P. Page,2 Louis B. Rice,1 and Robert A. Bonomo1*

Louis Stokes Cleveland Veterans Affairs Medical Center,1 Department of Biochemistry, Case Western Reserve University, Cleveland, Ohio,3 Basilea Pharmaceutica, Ltd., Basel, Switzerland,2 Department of Chemistry, Southern Methodist University, Dallas, Texas4

Received 20 February 2004/ Returned for modification 23 April 2004/ Accepted 7 October 2004

Penicillin-binding proteins (PBPs) catalyze the essential reactions in the biosynthesis of cell wall peptidoglycan from glycopeptide precursors. ß-Lactam antibiotics normally interfere with this process by reacting covalently with the active site serine to form a stable acyl-enzyme. The design of novel ß-lactams active against penicillin-susceptible and penicillin-resistant organisms will require a better understanding of the molecular details of this reaction. To that end, we compared the affinities of different ß-lactam antibiotics to a modified soluble form of a resistant Enterococcus faecium PBP5 ({Delta}1-36 rPBP5). The soluble protein, {Delta}1-36 rPBP5, was expressed in Escherichia coli and purified, and the NH2-terminal protein sequence was verified by amino acid sequencing. Using ß-lactams with different R1 side chains, we show that azlocillin has greater affinity for {Delta}1-36 rPBP5 than piperacillin and ampicillin (apparent Ki = 7 ± 0.3 µM, compared to 36 ± 3 and 51 ± 10 µM, respectively). Azlocillin also exhibits the most rapid acylation rate (apparent k2 = 15 ± 4 M–1 s–1). Meropenem demonstrates an affinity for {Delta}1-36 rPBP5 comparable to that of ampicillin (apparent Ki = 51 ± 15 µM) but is slower at acylating (apparent k2 = 0.14 ± 0.02 M–1 s–1). This characterization defines important structure-activity relationships for this clinically relevant type II transpeptidase, shows that the rate of formation of the acyl-enzyme is an essential factor determining the efficacy of a ß-lactam, and suggests that the specific side chain interactions of ß-lactams could be modified to improve inactivation of resistant PBPs.

* Corresponding author. Mailing address: Louis Stokes Cleveland Veterans Affairs Medical Center, 10701 East Blvd., Cleveland, OH 44106. Phone: (216) 791-3800, ext. 4399. Fax: (216) 231-3482. E-mail: Robert.Bonomo{at}med.va.gov.

Antimicrobial Agents and Chemotherapy, February 2005, p. 612-618, Vol. 49, No. 2
0066-4804/05/$08.00+0     doi:10.1128/AAC.49.2.612-618.2005
Copyright © 2005, American Society for Microbiology. All Rights Reserved.



This article has been cited by other articles:

  • Fan, X., Liu, Y., Smith, D., Konermann, L., Siu, K. W. M., Golemi-Kotra, D. (2007). Diversity of Penicillin-binding Proteins: RESISTANCE FACTOR FmtA OF STAPHYLOCOCCUS AUREUS. J. Biol. Chem. 282: 35143-35152 [Abstract] [Full Text]  
  • Fuda, C., Hesek, D., Lee, M., Heilmayer, W., Novak, R., Vakulenko, S. B., Mobashery, S. (2006). Mechanistic Basis for the Action of New Cephalosporin Antibiotics Effective against Methicillin- and Vancomycin-resistant Staphylococcus aureus. J. Biol. Chem. 281: 10035-10041 [Abstract] [Full Text]  


Copyright © 2009 by the American Society for Microbiology.   For an alternate route to Journals.ASM.org, visit: http://intl-journals.asm.org | More Info»