Electron cryotomography of Mycoplasma pneumoniae mutants correlates terminal organelle architectural features and function

Abstract

The Mycoplasma pneumoniae terminal organelle functions in adherence and gliding motility and is comprised of at least eleven substructures. We used electron cryotomography to correlate impaired gliding and adherence function with changes in architecture in diverse terminal organelle mutants. All eleven substructures were accounted for in the prkC, prpC and P200 mutants, and variably so for the HMW3 mutant. Conversely, no terminal organelle substructures were evident in HMW1 and HMW2 mutants. The P41 mutant exhibits a terminal organelle detachment phenotype and lacked the bowl element normally present at the terminal organelle base. Complementation restored this substructure, establishing P41 as either a component of the bowl element or required for its assembly or stability, and that this bowl element is essential to anchor the terminal organelle but not for leverage in gliding. Mutants II-3, III-4 and topJ exhibited a visibly lower density of protein knobs on the terminal organelle surface. Mutants II-3 and III-4 lack accessory proteins required for a functional adhesin complex, while the topJ mutant lacks a DnaJ-like co-chaperone essential for its assembly. Taken together, these observations expand our understanding of the roles of certain terminal organelle proteins in the architecture and function of this complex structure.

Sialylated Receptor Setting Influences Mycoplasma pneumoniae Attachment and Gliding Motility

“…The terminal organelle constitutes the gliding motor (Hasselbring and Krause, 2007), but the gliding mechanism is unique and poorly understood (Miyata, 2008). A gliding model based on electron cryotomography analysis asserts that conformational changes in the terminal organelle interior mobilize P1 adhesin complexes to treadmill on the mycoplasma surface (Henderson and Jensen, 2006;Kawamoto et al, 2016;Krause et al, 2018). Consistent with a P1 treadmill, P1-specific monoclonal antibodies detach gliding but not static mycoplasmas from an inert surface (Seto et al, 2005).…”

“…The terminal organelle is complex, with 11 distinct substructures evident by electron cryotomography (Henderson and Jensen, ). Most relevant to the current study are the protein knobs that line the outer surface of the terminal organelle at its distal end and correspond to P1 adhesin complexes (Layh‐Schmitt et al, ; Nakane et al, ; Kawamoto et al, ; Krause et al, ). Biochemical and mutant analyses indicate that these adhesin complexes include proteins P1, P40 and P90, which co‐localize generally to the terminal organelle (Baseman, Cole et al, ; Franzoso et al, ; Layh‐Schmitt et al, ; Nakane et al, ; Kawamoto et al, ).…”

Cellular and Structural Studies of Eukaryotic Cells by Cryo-Electron Tomography

“…Additionally, prokaryotes are ideal specimens for cryo-ET studies, as they can often be analyzed in toto. Several studies have yielded remarkable insights into bacterial structures and mechanisms, such as bacterial secretion systems [59,60], motility mechanisms [13,14,61,62,63], and the bacterial cytoskeleton [64].…”

Characterization of an Immunoglobulin Binding Protein (IbpM) From Mycoplasma pneumoniae

“…The link between attachment and virulence is exemplified by non-adherent Mycoplasma mutants which are nearly non-pathogenic (Waldo and Krause, 2006;Chaudhry et al, 2007). M. pneumoniae and M. genitalium encode a very complex protein network, the attachment organelle, which is responsible for their gliding motility and attachment to human epithelial cells (Balish and Krause, 2006;Kenri et al, 2018;Krause et al, 2018;Seybert et al, 2018). Proteins encoding subunits of this so-called tip structure seem to be responsible for enhanced survival of M. genitalium by antigenic and phase variation, a strategy described for many bacteria (van der Woude and Bäumler, 2004;Burgos et al, 2018).…”