TY - JOUR
T1 - Effect of porphyrins and host iron transport proteins on outer membrane protein expression in Porphyromonas (Bacteroides) gingivalis
T2 - identification of a novel 26 kDa hemin-repressible surface protein
AU - Bramanti, Thomas E.
AU - Holt, Stanley C.
N1 - Funding Information:
Protein determination. Total protein was determined using a modification of the bicinchoninic acid assay (Pierce) with human serum albumin as the standard . 48 This study was supported in part by Public Health Service grant DE00152 . Partial support was also obtained from DE08569 and DE07267 for the completion of this study . Dr Bramanti was a Dentist-Scientist Awardee during the tenure of this work .
PY - 1992/7
Y1 - 1992/7
N2 - Porphyromonas gingivalis is capable of in vitro growth when iron sources are either complexed to hemin or host iron transport proteins, or exist in an inorganic form. This study examined the effect of these iron sources on outer membrane protein (OMP) expression in P. gingivalis W50. Hemin (iron) starved P. gingivalis was transferred into growth medium containing hemin, hemoglobin, hemin-saturated human serum albumin, hemin-free human serum albumin, transferrin, lactoferrin, or inorganic iron. Surface proteins were identified by 125I-labeling and resolved by SDS-PAGE and autoradiography. When grown under hemin starved conditions, P. gingivalis W50 and related strains expressed a major 26 kDa OMP, as revealed by 125I-autoradiography. Autoradiographic analysis demonstrated the absence of this 26 kDa OMP from the P. gingivalis surface in hemin-containing environments. Growth of P. gingivalis W50 in the presence of host iron transport proteins (hemin-free) or inorganic iron resulted in surface expression of a 26 kDa OMP. The presence of protoporphyrin IX or substitution of hemin-associated iron with zinc, resulted in continued surface expression of the 26 kDa OMP, indicating that repressibility of this OMP required the coordination of iron to the protoporphyrin IX molecule (i.e. hemin). A survey of 125I-labeled OMPs from several hemin starved P. gingivalis and related strains, demonstrated that a hemin-repressible 26 kDa OMP occurred only in P. gingivalis. We report here a newly described 26 kDa hemin-regulated surface protein occurring in several strains of P. gingivalis which is expressed on the cell surface in hemin starved conditions and is lost from the cell surface in response to an environment containing iron coordinated specifically to protoporphyrin IX (i.e. hemin).
AB - Porphyromonas gingivalis is capable of in vitro growth when iron sources are either complexed to hemin or host iron transport proteins, or exist in an inorganic form. This study examined the effect of these iron sources on outer membrane protein (OMP) expression in P. gingivalis W50. Hemin (iron) starved P. gingivalis was transferred into growth medium containing hemin, hemoglobin, hemin-saturated human serum albumin, hemin-free human serum albumin, transferrin, lactoferrin, or inorganic iron. Surface proteins were identified by 125I-labeling and resolved by SDS-PAGE and autoradiography. When grown under hemin starved conditions, P. gingivalis W50 and related strains expressed a major 26 kDa OMP, as revealed by 125I-autoradiography. Autoradiographic analysis demonstrated the absence of this 26 kDa OMP from the P. gingivalis surface in hemin-containing environments. Growth of P. gingivalis W50 in the presence of host iron transport proteins (hemin-free) or inorganic iron resulted in surface expression of a 26 kDa OMP. The presence of protoporphyrin IX or substitution of hemin-associated iron with zinc, resulted in continued surface expression of the 26 kDa OMP, indicating that repressibility of this OMP required the coordination of iron to the protoporphyrin IX molecule (i.e. hemin). A survey of 125I-labeled OMPs from several hemin starved P. gingivalis and related strains, demonstrated that a hemin-repressible 26 kDa OMP occurred only in P. gingivalis. We report here a newly described 26 kDa hemin-regulated surface protein occurring in several strains of P. gingivalis which is expressed on the cell surface in hemin starved conditions and is lost from the cell surface in response to an environment containing iron coordinated specifically to protoporphyrin IX (i.e. hemin).
KW - Porphyromonas gingivalis
KW - hemin
KW - iron-repressible outer membrane protein
KW - outer membrane protein
KW - porphyrin
KW - protoporphyrin IX
UR - http://www.scopus.com/inward/record.url?scp=0026899697&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0026899697&partnerID=8YFLogxK
U2 - 10.1016/0882-4010(92)90032-J
DO - 10.1016/0882-4010(92)90032-J
M3 - Article
C2 - 1331700
AN - SCOPUS:0026899697
VL - 13
SP - 61
EP - 73
JO - Microbial Pathogenesis
JF - Microbial Pathogenesis
SN - 0882-4010
IS - 1
ER -