scholarly journals Cloning of the Gene Encoding the Actinobacillus actinomycetemcomitans Serotype b OmpA-Like Outer Membrane Protein

1999 ◽  
Vol 67 (2) ◽  
pp. 942-945 ◽  
Author(s):  
Hitoshi Komatsuzawa ◽  
Toshihisa Kawai ◽  
Mark E. Wilson ◽  
Martin A. Taubman ◽  
Motoyuki Sugai ◽  
...  
Keyword(s):  
Monoclonal Antibody ◽  
Amino Acid ◽  
Membrane Protein ◽  
Amino Acid Sequence ◽  
Molecular Mass ◽  
Outer Membrane ◽  
Outer Membrane Protein ◽  
Actinobacillus Actinomycetemcomitans ◽  
Gene Encoding ◽  
Serotype B

ABSTRACT The gene encoding an outer membrane protein A (OmpA)-like, heat-modifiable Omp of Actinobacillus actinomycetemcomitans ATCC 43718 (strain Y4, serotype b) was cloned by a PCR cloning procedure. DNA sequence analysis revealed that the gene encodes a protein of 346 amino acid residues with a molecular mass of 36.9 kDa. The protein expressed by the cloned gene reacted with a monoclonal antibody to the previously described 29-kDa Omp (Omp29) of strain Y4. This monoclonal antibody reacted specifically with Omp29 of A. actinomycetemcomitans (serotype b), but not with any Omp of Escherichia coli, including OmpA. This protein exhibited characteristic heat modifiability on sodium dodecyl sulfate-polyacrylamide gels, showing an apparent molecular mass of 29 kDa when unheated and a mass of 34 kDa when heated. The N-terminal amino acid sequence of the protein expressed inE. coli perfectly matched those deduced from the purified Omp29 of strain Y4. The deduced amino acid sequence of the gene coding for Omp29 from serotype b matched completely (except for valine at position 321) that of a recently reported omp34gene described for A. actinomycetemcomitans serotype c (NCTC 9710). Because of the conserved nature of the gene within these serotypes, we designated the gene described herein from serotype b asomp34.

scholarly journals Molecular Cloning, Sequencing, and Expression ofomp-40, the Gene Coding for the Major Outer Membrane Protein from the Acidophilic Bacterium Thiobacillus ferrooxidans

2000 ◽  
Vol 66 (6) ◽  
pp. 2318-2324 ◽  
Author(s):  
Nicolas Guiliani ◽  
Carlos A. Jerez
Keyword(s):  
Amino Acid ◽  
Membrane Protein ◽  
Amino Acid Sequence ◽  
Outer Membrane ◽  
Outer Membrane Protein ◽  
Thiobacillus Ferrooxidans ◽  
Sodium Dodecyl ◽  
Major Outer Membrane Protein ◽  
Gene Coding ◽  
Chemolithoautotrophic Bacteria

ABSTRACT Thiobacillus ferrooxidans is one of the chemolithoautotrophic bacteria important in industrial biomining operations. Some of the surface components of this microorganism are probably involved in adaptation to their acidic environment and in bacterium-mineral interactions. We have isolated and characterizedomp40, the gene coding for the major outer membrane protein from T. ferrooxidans. The deduced amino acid sequence of the Omp40 protein has 382 amino acids and a calculated molecular weight of 40,095.7. Omp40 forms an oligomeric structure of about 120 kDa that dissociates into the monomer (40 kDa) by heating in the presence of sodium dodecyl sulfate. The degree of identity of Omp40 amino acid sequence to porins from enterobacteria was only 22%. Nevertheless, multiple alignments of this sequence with those from several OmpC porins showed several important features conserved in the T. ferrooxidans surface protein, such as the approximate locations of 16 transmembrane beta strands, eight loops, including a large external L3 loop, and eight turns which allowed us to propose a putative 16-stranded beta-barrel porin structure for the protein. These results together with the previously known capacity of Omp40 to form ion channels in planar lipid bilayers strongly support its role as a porin in this chemolithoautotrophic acidophilic microorganism. Some characteristics of the Omp40 protein, such as the presence of a putative L3 loop with an estimated isoelectric point of 7.21 allow us to speculate that this can be the result of an adaptation of the acidophilic T. ferrooxidans to prevent free movement of protons across its outer membrane.

scholarly journals Bactericidal and Cross-Protective Activities of a Monoclonal Antibody Directed against Neisseria meningitidis NspA Outer Membrane Protein

1999 ◽  
Vol 67 (9) ◽  
pp. 4955-4959 ◽  
Author(s):  
Nathalie Cadieux ◽  
Martin Plante ◽  
Clément R. Rioux ◽  
Josée Hamel ◽  
Bernard R. Brodeur ◽  
...  
Keyword(s):  
Monoclonal Antibody ◽  
Amino Acid ◽  
Membrane Protein ◽  
Outer Membrane ◽  
Outer Membrane Protein ◽  
Predicted Amino Acid Sequence ◽  
Meningococcal Infections ◽  
Meningococcal Strain ◽  
Conserved Epitope

ABSTRACT The cross-bactericidal and cross-protective activities of a monoclonal antibody (MAb) named Me-7, which is directed against an antigenically highly conserved epitope on the meningococcal NspA protein, were studied. This MAb efficiently killed in vitro, in the presence of rabbit or human serum, 13 of 14 meningococcal strains tested, including 9 of 9, 2 of 3, and 2 of 2 strains of serotypes B, A, and C, respectively. MAb Me-7 also significantly reduced by more than 75% the levels of bacteremia recorded for mice challenged with 10 of 11 meningococcal strains tested. Analysis of the predicted amino acid sequence of the NspA protein from the meningococcal strain MCH88 (A:4:P1.10), which was not killed by MAb Me-7, indicated the presence of an additional glutamine residue at position 73, compared to the three other NspA sequences. The data presented in this study suggest that antibodies directed against this highly conserved outer membrane protein could protect against meningococcal infections.

scholarly journals Molecular Characterization of an Outer Membrane Protein ofActinobacillus actinomycetemcomitans Belonging to the OmpA Family

1998 ◽  
Vol 66 (1) ◽  
pp. 369-372 ◽  
Author(s):  
Peter A. White ◽  
Sean P. Nair ◽  
Mi-Jurng Kim ◽  
Michael Wilson ◽  
Brian Henderson
Keyword(s):  
Membrane Protein ◽  
Molecular Mass ◽  
Outer Membrane ◽  
Outer Membrane Protein ◽  
Genomic Library ◽  
Mature Protein ◽  
Gene Encoding ◽  
Localized Juvenile Periodontitis ◽  
Cloned Gene

ABSTRACT The major outer membrane protein (OMP) of Actinobacillus actinomycetemcomitans is an OmpA homolog that demonstrates electrophoretic heat modifiability. The gene encoding this protein was isolated from a genomic library of A. actinomycetemcomitansNCTC 9710 by immunoscreening with serum from a patient with localized juvenile periodontitis. Expression of the cloned gene inEscherichia coli and subsequent Western blot analysis revealed a protein with an approximate molecular mass of 34 kDa. The amino acid sequence predicted from the cloned gene demonstrated that the mature protein had a molecular mass of 34,911 Da and significant identity to members of the OmpA family of proteins. We have named the major OMP of A. actinomycetemcomitans Omp34, and its corresponding gene has been named omp34.

scholarly journals Conservation of msp, the gene encoding the major outer membrane protein of oral Treponema spp.

1997 ◽  
Vol 179 (4) ◽  
pp. 1082-1089 ◽  
Author(s):  
J C Fenno ◽  
G W Wong ◽  
P M Hannam ◽  
K H Müller ◽  
W K Leung ◽  
...  
Keyword(s):  
Membrane Protein ◽  
Outer Membrane ◽  
Outer Membrane Protein ◽  
Major Outer Membrane Protein ◽  
Gene Encoding
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