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Molecular design of Mycoplasma hominis Vaa adhesin
Author(s) -
Boesen Thomas,
Fedosova Natalya U.,
Kjeldgaard Morten,
Birkelund Svend,
Christiansen Gunna
Publication year - 2001
Publication title -
protein science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.353
H-Index - 175
eISSN - 1469-896X
pISSN - 0961-8368
DOI - 10.1110/ps.ps.31901
Subject(s) - bacterial adhesin , circular dichroism , recombinant dna , mycoplasma hominis , biology , sequence analysis , mollicutes , microbiology and biotechnology , gene , mycoplasma , genetics , biochemistry , escherichia coli
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 α‐helical content of ∼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.