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HmuY haemophore and gingipain proteases constitute a unique syntrophic system of haem acquisition by Porphyromonas gingivalis.

Smalley JW, Byrne DP, Birss AJ, Wojtowicz H, Sroka A, Potempa J, Olczak T - PLoS ONE (2011)

Bottom Line: HmuY was also capable of scavenging haem from oxyhaemoglobin pre-treated with the K-gingipain (Kgp).This is the first demonstration of a haemophore working in conjunction with proteases to acquire haem from haemoglobin.In addition, HmuY was able to extract haem from methaemalbumin, and could bind haem, either free in solution or from methaemoglobin, even in the presence of serum albumin.

View Article: PubMed Central - PubMed

Affiliation: Department of Clinical Infection, Microbiology and Immunology, Institute of Infection and Global Health, [corrected] University of Liverpool, Liverpool, United Kingdom. josmall@liv.ac.uk

ABSTRACT
Haem (iron protoporphyrin IX) is both an essential growth factor and virulence regulator for the periodontal pathogen Porphyromonas gingivalis, which acquires it mainly from haemoglobin via the sequential actions of the R- and K-specific gingipain proteases. The haem-binding lipoprotein haemophore HmuY and its cognate receptor HmuR of P. gingivalis, are responsible for capture and internalisation of haem. This study examined the role of the HmuY in acquisition of haem from haemoglobin and the cooperation between HmuY and gingipain proteases in this process. Using UV-visible spectroscopy and polyacrylamide gel electrophoresis, HmuY was demonstrated to wrest haem from immobilised methaemoglobin and deoxyhaemoglobin. Haem extraction from oxyhaemoglobin was facilitated after oxidation to methaemoglobin by pre-treatment with the P. gingivalis R-gingipain A (HRgpA). HmuY was also capable of scavenging haem from oxyhaemoglobin pre-treated with the K-gingipain (Kgp). This is the first demonstration of a haemophore working in conjunction with proteases to acquire haem from haemoglobin. In addition, HmuY was able to extract haem from methaemalbumin, and could bind haem, either free in solution or from methaemoglobin, even in the presence of serum albumin.

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Effect of ferrihaem binding on the electrophoretic mobility of HmuY.The presence of haem in the complex with HmuY is confirmed by haem-peroxidise activity (bottom panel).
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pone-0017182-g002: Effect of ferrihaem binding on the electrophoretic mobility of HmuY.The presence of haem in the complex with HmuY is confirmed by haem-peroxidise activity (bottom panel).

Mentions: Complexation of HmuY with an equimolar amount of ferrihaem increased significantly the electrophoretic mobility of the HmuY as analyzed by the native PAGE (Fig. 2). This effect is presumed to occur as a consequence of bis-histidine ligation of haem by the HmuY, resulting in a haem-HmuY complex in which the ionised carboxylate groups of the iron porphyrin impart additional negative charge, which makes the liganded holoHmuY migrate faster than apoHmuY in the electric field during native PAGE.


HmuY haemophore and gingipain proteases constitute a unique syntrophic system of haem acquisition by Porphyromonas gingivalis.

Smalley JW, Byrne DP, Birss AJ, Wojtowicz H, Sroka A, Potempa J, Olczak T - PLoS ONE (2011)

Effect of ferrihaem binding on the electrophoretic mobility of HmuY.The presence of haem in the complex with HmuY is confirmed by haem-peroxidise activity (bottom panel).
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3040768&req=5

pone-0017182-g002: Effect of ferrihaem binding on the electrophoretic mobility of HmuY.The presence of haem in the complex with HmuY is confirmed by haem-peroxidise activity (bottom panel).
Mentions: Complexation of HmuY with an equimolar amount of ferrihaem increased significantly the electrophoretic mobility of the HmuY as analyzed by the native PAGE (Fig. 2). This effect is presumed to occur as a consequence of bis-histidine ligation of haem by the HmuY, resulting in a haem-HmuY complex in which the ionised carboxylate groups of the iron porphyrin impart additional negative charge, which makes the liganded holoHmuY migrate faster than apoHmuY in the electric field during native PAGE.

Bottom Line: HmuY was also capable of scavenging haem from oxyhaemoglobin pre-treated with the K-gingipain (Kgp).This is the first demonstration of a haemophore working in conjunction with proteases to acquire haem from haemoglobin.In addition, HmuY was able to extract haem from methaemalbumin, and could bind haem, either free in solution or from methaemoglobin, even in the presence of serum albumin.

View Article: PubMed Central - PubMed

Affiliation: Department of Clinical Infection, Microbiology and Immunology, Institute of Infection and Global Health, [corrected] University of Liverpool, Liverpool, United Kingdom. josmall@liv.ac.uk

ABSTRACT
Haem (iron protoporphyrin IX) is both an essential growth factor and virulence regulator for the periodontal pathogen Porphyromonas gingivalis, which acquires it mainly from haemoglobin via the sequential actions of the R- and K-specific gingipain proteases. The haem-binding lipoprotein haemophore HmuY and its cognate receptor HmuR of P. gingivalis, are responsible for capture and internalisation of haem. This study examined the role of the HmuY in acquisition of haem from haemoglobin and the cooperation between HmuY and gingipain proteases in this process. Using UV-visible spectroscopy and polyacrylamide gel electrophoresis, HmuY was demonstrated to wrest haem from immobilised methaemoglobin and deoxyhaemoglobin. Haem extraction from oxyhaemoglobin was facilitated after oxidation to methaemoglobin by pre-treatment with the P. gingivalis R-gingipain A (HRgpA). HmuY was also capable of scavenging haem from oxyhaemoglobin pre-treated with the K-gingipain (Kgp). This is the first demonstration of a haemophore working in conjunction with proteases to acquire haem from haemoglobin. In addition, HmuY was able to extract haem from methaemalbumin, and could bind haem, either free in solution or from methaemoglobin, even in the presence of serum albumin.

Show MeSH