The mycoplasma surface proteins MIB and MIP promote the dissociation of the antibody-antigen interaction.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 33674316.
- Also identified by DOI 10.1126/sciadv.abf2403 and PMC identifier 7935358.
- Licence recorded as CC BY-NC.
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Abstract
Mycoplasma immunoglobulin binding (MIB) and mycoplasma immunoglobulin protease (MIP) are surface proteins found in the majority of mycoplasma species, acting sequentially to capture antibodies and cleave off their V<sub>H</sub> domains. Cryo-electron microscopy structures show how MIB and MIP bind to a Fab fragment in a "hug of death" mechanism. As a result, the orientation of the V<sub>L</sub> and V<sub>H</sub> domains is twisted out of alignment, disrupting the antigen binding site. We also show that MIB-MIP has the ability to promote the dissociation of the antibody-antigen complex. This system is functional in cells and protects mycoplasmas from antibody-mediated agglutination. These results highlight the key role of the MIB-MIP system in immunity evasion by mycoplasmas through an unprecedented mechanism, and open exciting perspectives to use these proteins as potential tools in the antibody field.
Medical subject headings
- Mycoplasma