The mycoplasma surface proteins MIB and MIP promote the dissociation of the antibody-antigen interaction

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 VH 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 VL and VH 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.

Chained Structure of Dimeric F 1 -like ATPase in Mycoplasma mobile Gliding Machinery

“…This case may be reminiscent of that for dynein, a motor in eukaryotes, which evolved from a widely conserved AAA (ATPases associated with diverse cellular activities)+ protein, in which multiple subunits of ATPases perform functional rotation ( 41 , 42 ). Sequence analyses have shown that mycoplasma type 3 ATPase is also related to F 1 -ATPase, and its role has been suggested to promote substrate turnover in the MIB-MIP system ( 33 ). If type 3 ATPase provides the force to change the conformation of a hydrolytic enzyme, its role in force generation is common with that of type 2, the gliding motor.…”

“…Type 1, found in all mycoplasmas, is a typical operon encoding F 1 F o -ATPase and is likely to function as a proton pump to maintain membrane potential. Type 3 is found in mycoplasmas that have an MIB-MIP system to cleave host immunoglobulins ( 33 ). Type 2 is only found in four Mycoplasma species, including M. mobile .…”

Towards A Novel Multi-Epitopes Chimeric Vaccine for Simulating Strong Immune Responses and Protection against Morganella morganii

“…Surface localized proteins are more potent for generating an immune response compared to other localized proteins. These proteins contain antigenic determinants and are in frequent contact with the host [84]. Moreover, they function as virulent proteins by activating immune signaling pathways [37].…”

Attenuation of Mycoplasma hyopneumoniae Strain ES-2 and Comparative Genomic Analysis of ES-2 and Its Attenuated Form ES-2L

“…E5E95_00610 gene was annotated as adhesin protein by the NCBI Search database; it experienced two non-synonymous gene mutations (C-G and C-T) according to the results of SNP analysis (Supplementary File 2), which suggested that this gene may be a new potential virulence factor, although its biological significance needs further verification. More importantly, mycoplasmas can evade the killing of the host's humoral immunity by the MIB-MIP system that captures and cleaves immunoglobulin G (61)(62)(63). E5E95_03535 was an important virulence gene encoding putative immunoglobulin-blocking protein, which could bind to the immunoglobulin in the serum to cleave the immunoglobulin, playing a crucial role in evading the neutralization of serum antibodies.…”