Inhibition of Staphylococcus aureus pathogenesis in vitro and in vivo by RAP-binding peptides.
Staphylococcus aureus cause many diseases by producing toxins, whose synthesis is regulated by quorum-sensing mechanisms. S. aureus secretes a protein termed RNAIII activating protein (RAP) which autoinduces toxin production via the phosphorylation of is target protein TRAP. Mice vaccinated with RAP were protected from S. aureus infection, suggesting that RAP is an useful target for selecting potential therapeutic molecules to inhibit S. aureus pathogenesis. We show here that RAP (native and recombinant) was used to select RAP-binding peptides (RBPs) from a random 12-mer phage-displayed peptide library. Two RBPs were shown to inhibit RNAIII production in vitro (used a marker for pathogenesis). The peptide WPFAHWPWQYPR, which had the strongest inhibitory activity, was chemically synthesized and also expressed in Escherichia coli as a GST-fusion. Both synthetic peptide and GST-fusion peptide decreased RNAIII levels in a dose-dependent manner. The GST-fusion peptide was also shown to protect mice from a S. aureus infection in vivo (tested in a murine cutaneous S. aureus infection model). Our results suggest the potential use of RAP-binding proteins in treating clinical S. aureus infections.
Yang
Guang
G
Beijing Institute of Basic Medical Sciences, P.O. Box 130 (3), Beijing 100850, China.
Cheng
Huichai
H
Liu
Chuan
C
Xue
Yanning
Y
Gao
Yaping
Y
Liu
Nongle
N
Gao
Bo
B
Wang
Dongping
D
Li
Shanru
S
Shen
Beifen
B
Shao
Ningsheng
N
D000818:Animals; D001426:Bacterial Proteins / Q000037:antagonists & inhibitors / Q000302:isolation & purification / Q000378:metabolism*; D002352:Carrier Proteins / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism* / Q000494:pharmacology*; D002481:Cellulitis / Q000382:microbiology / Q000517:prevention & control; D051379:Mice; D019151:Peptide Library; D011485:Protein Binding; D016372:RNA, Antisense / Q000096:biosynthesis; D012329:RNA, Bacterial / Q000096:biosynthesis; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism / Q000494:pharmacology; D013203:Staphylococcal Infections / Q000382:microbiology / Q000517:prevention & control; D013211:Staphylococcus aureus / Q000187:drug effects* / Q000378:metabolism / Q000472:pathogenicity*
D001426:Bacterial Proteins; D002352:Carrier Proteins; D019151:Peptide Library; C428447:RAP protein, Staphylococcus aureus; D016372:RNA, Antisense; D012329:RNA, Bacterial; C096035:RNAIII, Staphylococcus aureus; D011993:Recombinant Fusion Proteins