TY - JOUR
T1 - Structure and protective efficacy of the Staphylococcus aureus autocleaving protease EpiP
AU - Kuhn, Misty L.
AU - Prachi, Prachi
AU - Minasov, George
AU - Shuvalova, Ludmilla
AU - Ruan, Jiapeng
AU - Dubrovska, Ievgeniia
AU - Winsor, James
AU - Giraldi, Monica
AU - Biagini, Massimiliano
AU - Liberatori, Sabrina
AU - Savino, Silvana
AU - Bagnoli, Fabio
AU - Anderson, Wayne F.
AU - Grandi, Guido
PY - 2014/4
Y1 - 2014/4
N2 - Despite the global medical needs associated with Staphylococcus aureus infections, no licensed vaccines are currently available. We identified and characterized a protein annotated as an epidermin leader peptide processing serine protease (EpiP), as a novel S. aureus vaccine candidate. In addition, we determined the structure of the recombinant protein (rEpiP) by X-ray crystallography. The crystal structure revealed that rEpiP was cleaved somewhere between residues 95 and 100, and we found that the cleavage occurs through an autocatalytic intramolecular mechanism. The protein expressed by S. aureus cells also appeared to undergo a similar processing event. To determine whether the protein acts as a serine protease, we mutated the hypothesized catalytic serine 393 residue to alanine, generating rEpiP-S393A. The crystal structure of this mutant protein showed that the polypeptide chain was not cleaved and was not interacting stably with the active site. Indeed, rEpiP-S393A was shown to be impaired in its protease activity. Mice vaccinated with rEpiP were protected from S. aureus infection (34% survival, P̃0.0054). Moreover, the protective efficacy generated by rEpiP and rEpiP-S393A was comparable, implying that the noncleaving mutant could be used for vaccination purposes.
AB - Despite the global medical needs associated with Staphylococcus aureus infections, no licensed vaccines are currently available. We identified and characterized a protein annotated as an epidermin leader peptide processing serine protease (EpiP), as a novel S. aureus vaccine candidate. In addition, we determined the structure of the recombinant protein (rEpiP) by X-ray crystallography. The crystal structure revealed that rEpiP was cleaved somewhere between residues 95 and 100, and we found that the cleavage occurs through an autocatalytic intramolecular mechanism. The protein expressed by S. aureus cells also appeared to undergo a similar processing event. To determine whether the protein acts as a serine protease, we mutated the hypothesized catalytic serine 393 residue to alanine, generating rEpiP-S393A. The crystal structure of this mutant protein showed that the polypeptide chain was not cleaved and was not interacting stably with the active site. Indeed, rEpiP-S393A was shown to be impaired in its protease activity. Mice vaccinated with rEpiP were protected from S. aureus infection (34% survival, P̃0.0054). Moreover, the protective efficacy generated by rEpiP and rEpiP-S393A was comparable, implying that the noncleaving mutant could be used for vaccination purposes.
KW - Abscess
KW - Epidermin leader peptide processing serine protease
KW - Immunogenicity
KW - Lantibiotic
KW - Pathogenesis
KW - Vaccine
UR - http://www.scopus.com/inward/record.url?scp=84901037097&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84901037097&partnerID=8YFLogxK
U2 - 10.1096/fj.13-241737
DO - 10.1096/fj.13-241737
M3 - Article
C2 - 24421400
AN - SCOPUS:84901037097
SN - 0892-6638
VL - 28
SP - 1780
EP - 1793
JO - FASEB Journal
JF - FASEB Journal
IS - 4
ER -