Characterization of novel LPXTG-containing proteins of Staphylococcus aureus identified from genome sequences.
Twenty-one genes encoding surface proteins belonging to the LPXTG family have been identified by in silico analysis of six Staphylococcus aureus genome sequences. Eleven genes encode previously described proteins, while 10 have not yet been characterized. Of these, eight contain the cell-wall sorting signal LPXTG responsible for covalently anchoring proteins to the cell-wall peptidoglycan. The remaining two, SasF and SasD, harbour a single residue variation in the fourth position of the LPXTG motif (LPXAG). Western blotting of lysostaphin-solubilized S. aureus cell-wall proteins demonstrated the release of SasF in the cell-wall fraction, indicating that proteins carrying LPXAG are sorted normally. Analysis of primary sequences of the Staphylococcus aureus surface (Sas) proteins indicated that several share a similar structural organization and a common signal sequence with previously characterized LPXTG proteins of S. aureus and other Gram-positive cocci. Protein SasG has 128 residue B repeats that are almost identical at the DNA level. PCR analysis indicated that recombinants with repeat length variations are present in the bacterial population whereas they are not detectable in the B-repeat-encoding region of sdrD. The sasG and sasH genes are significantly associated with invasive disease isolates compared to nasal carriage isolates. Several IgG samples purified from patients recovering from S. aureus infections had higher titres against Sas proteins than control IgG, suggesting that expression occurred during infection in some patients.
Roche
Fiona M
FM
Department of Microbiology, Moyne Institute of Preventive Medicine, Trinity College, Dublin 2, Ireland.
Massey
Ruth
R
Nuffield Department of Clinical Laboratory Sciences, University of Oxford, John Radcliffe Hospital, Oxford OX3 9DU, UK.
Peacock
Sharon J
SJ
Nuffield Department of Clinical Laboratory Sciences, University of Oxford, John Radcliffe Hospital, Oxford OX3 9DU, UK.
Day
Nicholas P J
NPJ
Nuffield Department of Clinical Laboratory Sciences, University of Oxford, John Radcliffe Hospital, Oxford OX3 9DU, UK.
Visai
Livia
L
Department of Biochemistry, University of Pavia, 27100 Pavia, Italy.
Speziale
Pietro
P
Department of Biochemistry, University of Pavia, 27100 Pavia, Italy.
Lam
Alex
A
Department of Microbiology and Immunobiology, The Queen's University of Belfast, Grosvenor Road, Belfast BT12 6BN, UK.
Pallen
Mark
M
Department of Microbiology and Immunobiology, The Queen's University of Belfast, Grosvenor Road, Belfast BT12 6BN, UK.
Foster
Timothy J
TJ
Department of Microbiology, Moyne Institute of Preventive Medicine, Trinity College, Dublin 2, Ireland.
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D000907:Antibodies, Bacterial / Q000097:blood; D001426:Bacterial Proteins / Q000737:chemistry* / Q000235:genetics* / Q000378:metabolism; D002353:Carrier State / Q000382:microbiology; D016680:Genome, Bacterial; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood; D008565:Membrane Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D008875:Middle Aged; D008969:Molecular Sequence Data; D016133:Polymerase Chain Reaction; D011994:Recombinant Proteins / Q000276:immunology / Q000378:metabolism; D017422:Sequence Analysis, DNA; D013203:Staphylococcal Infections / Q000382:microbiology; D013211:Staphylococcus aureus / Q000235:genetics / Q000378:metabolism / Q000472:pathogenicity*
D000907:Antibodies, Bacterial; D001426:Bacterial Proteins; D007074:Immunoglobulin G; D008565:Membrane Proteins; D011994:Recombinant Proteins