title: Human beta-defensin 3 inhibits cell wall biosynthesis in Staphylococci.
abstract: Human beta-defensin 3 (hBD3) is a highly charged (+11) cationic host defense peptide, produced by epithelial cells and neutrophils. hBD3 retains antimicrobial activity against a broad range of pathogens, including multiresistant Staphylococcus aureus, even under high-salt conditions. Whereas antimicrobial host defense peptides are assumed to act by permeabilizing cell membranes, the transcriptional response pattern of hBD3-treated staphylococcal cells resembled that of vancomycin-treated cells (V. Sass, U. Pag, A. Tossi, G. Bierbaum, and H. G. Sahl, Int. J. Med. Microbiol. 298:619-633, 2008) and suggested that inhibition of cell wall biosynthesis is a major component of the killing process. hBD3-treated cells, inspected by transmission electron microscopy, showed localized protrusions of cytoplasmic contents, and analysis of the intracellular pool of nucleotide-activated cell wall precursors demonstrated accumulation of the final soluble precursor, UDP-MurNAc-pentapeptide. Accumulation is typically induced by antibiotics that inhibit membrane-bound steps of cell wall biosynthesis and also demonstrates that hBD3 does not impair the biosynthetic capacity of cells and does not cause gross leakage of small cytoplasmic compounds. In in vitro assays of individual membrane-associated cell wall biosynthesis reactions (MraY, MurG, FemX, and penicillin-binding protein 2 [PBP2]), hBD3 inhibited those enzymes which use the bactoprenol-bound cell wall building block lipid II as a substrate; quantitative analysis suggested that hBD3 may stoichiometrically bind to lipid II. We report that binding of hBD3 to defined, lipid II-rich sites of cell wall biosynthesis may lead to perturbation of the biosynthesis machinery, resulting in localized lesions in the cell wall as demonstrated by electron microscopy. The lesions may then allow for osmotic rupture of cells when defensins are tested under low-salt conditions.
authors.affiliation: Institute of Medical Microbiology, Immunology and ParasitologyPharmaceutical Microbiology Section, University of Bonn,53105 Bonn, Germany.
authors.forename: Vera
authors.initials: V
authors.lastname: Sass
authors.forename: Tanja
authors.initials: T
authors.lastname: Schneider
authors.forename: Miriam
authors.initials: M
authors.lastname: Wilmes
authors.forename: Christian
authors.initials: C
authors.lastname: Körner
authors.forename: Alessandro
authors.initials: A
authors.lastname: Tossi
authors.forename: Natalia
authors.initials: N
authors.lastname: Novikova
authors.forename: Olga
authors.initials: O
authors.lastname: Shamova
authors.forename: Hans-Georg
authors.initials: HG
authors.lastname: Sahl
mesh_terms: D002473:Cell Wall / Q000378:metabolism* / Q000648:ultrastructure; D003593:Cytoplasm / Q000737:chemistry; D006801:Humans; D046529:Microscopy, Electron, Transmission; D013211:Staphylococcus aureus / Q000276:immunology* / Q000648:ultrastructure; D014538:Uridine Diphosphate N-Acetylmuramic Acid / Q000031:analogs & derivatives / Q000032:analysis / Q000378:metabolism; D023083:beta-Defensins / Q000276:immunology*
chemical_list: C422950:DEFB103A protein, human; D014538:Uridine Diphosphate N-Acetylmuramic Acid; D023083:beta-Defensins; C069249:muramyl-NAc-(pentapeptide)pyrophosphoryl-undecaprenol; C002225:UDP-N-acetylmuramic acid pentapeptide
references.citation: Eur J Biochem. 1999 Jan;259(1-2):360-9
references.pmid: 9914515
references.citation: Biopolymers. 2002;66(4):236-48
references.pmid: 12491537
references.citation: Adv Microb Physiol. 1995;37:135-75
references.pmid: 8540420
references.citation: BMC Genomics. 2009 Sep 14;10:429
references.pmid: 19751498
references.citation: Mol Microbiol. 1998 Oct;30(2):317-27
references.pmid: 9791177
references.citation: Antimicrob Agents Chemother. 2005 May;49(5):1727-32
references.pmid: 15855488
references.citation: J Biol Chem. 2001 Feb 23;276(8):5707-13
references.pmid: 11085990
references.citation: Nature. 2002 Jan 24;415(6870):389-95
references.pmid: 11807545
references.citation: J Biol Chem. 2006 Jul 21;281(29):19861-71
references.pmid: 16720578
references.citation: J Biol Chem. 1999 Mar 26;274(13):8405-10
references.pmid: 10085071
references.citation: Antimicrob Agents Chemother. 2009 Apr;53(4):1610-8
references.pmid: 19164139
references.citation: Comb Chem High Throughput Screen. 2005 May;8(3):209-17
references.pmid: 15892623
references.citation: Curr Opin Immunol. 1998 Feb;10(1):41-4
references.pmid: 9523109
references.citation: Mol Microbiol. 2003 Aug;49(3):807-21
references.pmid: 12864861
references.citation: Curr Protein Pept Sci. 2005 Feb;6(1):35-51
references.pmid: 15638767
references.citation: J Antimicrob Chemother. 2008 Feb;61(2):341-52
references.pmid: 18174202
references.citation: Trends Biotechnol. 1998 Feb;16(2):82-8
references.pmid: 9487736
references.citation: FEMS Microbiol Lett. 2002 Jan 2;206(1):9-18
references.pmid: 11786250
references.citation: Curr Opin Immunol. 2002 Feb;14(1):96-102
references.pmid: 11790538
references.citation: Antimicrob Agents Chemother. 2006 Oct;50(10):3424-34
references.pmid: 17005825
references.citation: Mol Microbiol. 2000 Mar;35(6):1518-29
references.pmid: 10760151
references.citation: Mol Microbiol. 2004 Jul;53(2):675-85
references.pmid: 15228543
references.citation: Biochem J. 2003 Sep 15;374(Pt 3):707-14
references.pmid: 12795637
references.citation: J Pept Sci. 2008 Apr;14(4):518-23
references.pmid: 18085509
references.citation: Cell Mol Life Sci. 2006 Feb;63(4):469-86
references.pmid: 16416029
references.citation: Cell Mol Life Sci. 2006 Jun;63(11):1294-313
references.pmid: 16710608
references.citation: Biopolymers. 1998;47(6):451-63
references.pmid: 10333737
references.citation: FEBS Lett. 2008 Jun 25;582(15):2299-302
references.pmid: 18519036
references.citation: FEMS Microbiol Lett. 2004 Feb 9;231(1):67-71
references.pmid: 14769468
references.citation: J Bacteriol. 1988 Jan;170(1):84-8
references.pmid: 3335484
references.citation: Int J Med Microbiol. 2008 Oct;298(7-8):619-33
references.pmid: 18455476
references.citation: Nat Rev Microbiol. 2006 Jul;4(7):529-36
references.pmid: 16778838
references.citation: J Bacteriol. 2006 Feb;188(3):1120-33
references.pmid: 16428416
references.citation: Microbiol Mol Biol Rev. 2005 Dec;69(4):585-607
references.pmid: 16339737
references.citation: Biopolymers. 2000;55(1):4-30
references.pmid: 10931439
references.citation: J Bacteriol. 1985 May;162(2):833-6
references.pmid: 3921529
references.citation: Mol Microbiol. 2008 Jun;68(5):1315-27
references.pmid: 18430139
references.citation: Trends Microbiol. 2000 Sep;8(9):402-10
references.pmid: 10989307
references.citation: Proc Natl Acad Sci U S A. 2000 May 9;97(10):5028-30
references.pmid: 10805764
references.citation: J Leukoc Biol. 2005 Apr;77(4):466-75
references.pmid: 15582982
references.citation: Nat Immunol. 2005 Jun;6(6):551-7
references.pmid: 15908936
references.citation: FEMS Microbiol Lett. 1989 Apr;49(2-3):223-7
references.pmid: 2501145
references.citation: Curr Pharm Des. 2002;8(9):743-61
references.pmid: 11945169
references.citation: FASEB J. 2006 Jan;20(1):35-42
references.pmid: 16394265
references.citation: J Biol Chem. 2002 Mar 8;277(10):8279-89
references.pmid: 11741980
references.citation: J Bacteriol. 1991 Jun;173(11):3425-31
references.pmid: 2045364
references.citation: J Bacteriol. 1988 May;170(5):2197-201
references.pmid: 3283106