Molecular design of Mycoplasma hominis Vaa adhesin.
The variable adherence-associated (Vaa) adhesin of the opportunistic human pathogen Mycoplasma hominis is a surface-exposed, membrane-associated protein involved in the attachment of the bacterium to host cells. The molecular masses of recombinant 1 and 2 cassette forms of the protein determined by a light-scattering (LS) method were 23.9 kD and 36.5 kD, respectively, and corresponded to their monomeric forms. Circular dichroism (CD) spectroscopy of the full-length forms indicated that the Vaa protein has an alpha-helical content of approximately 80%. Sequence analysis indicates the presence of coiled-coil domains in both the conserved N-terminal and antigenic variable C-terminal part of the Vaa adhesin. Experimental results obtained with recombinant proteins corresponding to the N- or C-terminal parts of the shortest one-cassette form of the protein were consistent with the hypothesis of two distinct coiled-coil regions. The one-cassette Vaa monomer appears to be an elongated protein with a axial shape ratio of 1:10. Analysis of a two-cassette Vaa type reveals a similar axial shape ratio. The results are interpreted in terms of the topological organization of the Vaa protein indicating the localization of the adherence-mediating structure.
Boesen
T
T
Department of Medical Microbiology and Immunology, University of Aarhus, DK-8000 Aarhus C, Denmark. thoesen@biobase.dk
Fedosova
N U
NU
Kjeldgaard
M
M
Birkelund
S
S
Christiansen
G
G
D018829:Adhesins, Bacterial; D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry* / Q000235:genetics / Q000302:isolation & purification; D002846:Chromatography, Affinity; D002942:Circular Dichroism; D003001:Cloning, Molecular; D004591:Electrophoresis, Polyacrylamide Gel; D008027:Light; D008565:Membrane Proteins; D008958:Models, Molecular; D008969:Molecular Sequence Data; D019535:Mycoplasma hominis / Q000737:chemistry*; D010957:Plasmids / Q000378:metabolism; D016133:Polymerase Chain Reaction; D011485:Protein Binding; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D011994:Recombinant Proteins / Q000737:chemistry / Q000378:metabolism; D012542:Scattering, Radiation; D012984:Software; D014867:Water
D018829:Adhesins, Bacterial; D001426:Bacterial Proteins; D008565:Membrane Proteins; D011994:Recombinant Proteins; C115186:Vaa protein, Mycoplasma hominis; D014867:Water