scholarly journals Mfa5 from Porphyromonas gingivalis: a von Willebrand factor domain and an intramolecular isopeptide bond in a Gram-negative bacterial fimbrial protein

2020 ◽  
Author(s):  
Thomas Heidler ◽  
Rolf Claesson ◽  
Karina Persson

Abstract The Gram-negative bacterium Porphyromonas gingivalis is a secondary colonizer of the oral biofilm and is involved in the onset and progression of periodontitis. Its fimbriae, of type-V, are important for attachment to other microorganisms in the biofilm and for adhesion to host cells. The fimbriae are assembled from five proteins encoded by the mfa1 operon, of which Mfa5 is one of the ancillary tip proteins. Here we report the X-ray structure of the N-terminal half of Mfa5, which reveals a von Willebrand factor domain and two IgG-like domains. One of the IgG-like domains is stabilized by an intramolecular isopeptide bond, which is the first such bond observed in a Gram-negative bacterium. These features make Mfa5 structurally more related to streptococcal adhesins than to the other P. gingivalis Mfa proteins. The structure reported here indicates that horizontal gene transfer has occurred among the bacteria that within the oral biofilm.

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Thomas V. Heidler ◽  
Karin Ernits ◽  
Agnieszka Ziolkowska ◽  
Rolf Claesson ◽  
Karina Persson

AbstractThe Gram-negative bacterium Porphyromonas gingivalis is a secondary colonizer of the oral biofilm and is involved in the onset and progression of periodontitis. Its fimbriae, of type-V, are important for attachment to other microorganisms in the biofilm and for adhesion to host cells. The fimbriae are assembled from five proteins encoded by the mfa1 operon, of which Mfa5 is one of the ancillary tip proteins. Here we report the X-ray structure of the N-terminal half of Mfa5, which reveals a von Willebrand factor domain and two IgG-like domains. One of the IgG-like domains is stabilized by an intramolecular isopeptide bond, which is the first such bond observed in a Gram-negative bacterium. These features make Mfa5 structurally more related to streptococcal adhesins than to the other P. gingivalis Mfa proteins. The structure reported here indicates that horizontal gene transfer has occurred among the bacteria within the oral biofilm.


1986 ◽  
Vol 55 (02) ◽  
pp. 276-278 ◽  
Author(s):  
F Brosstad ◽  
Inge Kjønniksen ◽  
B Rønning ◽  
H Stormorken

SummaryA method for visualization of the multimeric forms of von Willebrand Factor (vWF) in plasma and platelets is described. The method is based upon: 1) Separation of the vWF multimers by SDS-agarose electrophoresis, 2) Subsequent blotting of the vWF multimers onto nitrocellulose, 3) Immunolocalization and visualization of the vWF pattern by the sequential incubation of the blot with a) primary vWF antiserum, b) peroxidase- or beta-galactosidase-conjugated secondary antibodies and a relevant chromogenic substrate.


1988 ◽  
Vol 60 (02) ◽  
pp. 182-187 ◽  
Author(s):  
Morio Aihara ◽  
Ken Tamura ◽  
Ryuko Kawarada ◽  
Keizou Okawa ◽  
Yutaka Yoshida

SummaryThe adhesion of human fixed washed platelets (FWP) to collagen was decreased after treatment with Serratia marcescens protease (SP), which removed 95% of the glycocalicin from platelet membrane glycoprotein (GP) lb. However, the diminished adhesion of SP treated FWP to collagen could still be increased in the presence of purified von Willebrand factor (vWF). This ability of vWF to increase FWP adhesion to collagen is defined as collagen cofactor (CCo). The adhesion of FWP to collagen was not affected by a monoclonal antibody (MAb) to GP Ilb/IIIa (10E5), that inhibits ADP and collagen induced platelet aggregation. On the other hand, it was decreased by 50% by a MAb to GP lb (6D1), that inhibits ristocetin induced platelet aggregation. Adhesion of FWP in buffer to collagen was completely inhibited by Ricinus communis agglutinin I or concanavalin A, while Lens culinalis agglutinin and wheat germ agglutinin showed 50% inhibition. The FWP adhesion to collagen in the presence of vWF (normal plasma) was unaffected by MAbs to GP Ilb/IIIa (10E5, P2, HPL1) but was decreased to 32-38% by MAbs to GP lb (6D1, AN51, HPL11). A MAb to vWF (CLB-RAg 35), that inhibits ristocetin induced binding of vWF to platelets, decreased the CCo of normal plasma by 70%. The MAb, CLB-RAg 201, that inhibits the binding of vWF to collagen, completely inhibited the CCo of normal plasma. In conclusion, our data suggest that (1) GP lb has a partial role in FWP adhesion to collagen; (2) the binding of vWF to collagen is required for the expression of CCo; (3) CCo is partly mediated through GP lb; but (4) other platelet membrane protein(s) besides GP lb or GP Ilb/IIIa must also be involved in FWP-vWF-collagen interactions.


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