Structural and polypeptide differences between envelopes of infective and reproductive life cycle forms of Chlamydia spp

Abstract

Significant differences in cysteine-containing proteins and detergent-related solubility properties were observed between outer membrane protein complexes of reproductive (reticulate body) and infective (elementary body) forms of Chlamydia psittaci (6BC). Elementary bodies harvested at 48 h postinfection possessed a 40-kilodalton major outer membrane protein and three extraordinarily cysteine-rich outer membrane proteins of 62, 59, and 12 kilodaltons, all of which were not solubilized by sodium dodecyl sulfate in the absence of thiol reagents. Intracellularly dividing reticulate bodies harvested at 21 h postinfection were severely deficient in the cysteine-rich proteins but possessed almost as much major outer membrane protein as did the elementary bodies. Most of the major outer membrane protein of reticulate bodies was solubilized by sodium dodecyl sulfate and was present in envelopes as monomers, although a proportion formed disulfide-cross-linked oligomers. By 21 to 24 h postinfection, reticulate bodies commenced synthesis of the cysteine-rich proteins which were found in outer membranes as disulfide-cross-linked complexes. The outer membranes of reticulate bodies of Chlamydia trachomatis (LGV434) also were found to be deficient in cysteine-rich proteins and to be more susceptible to dissociation in sodium dodecyl sulfate than were outer membranes of elementary bodies.

Chlamydia attachment to mammalian cells requires protein disulfide isomerase

“…It could be considered that the role of GAG in chlamydial attachment, and especially infectivity, may involve PDI function in chlamydial interaction with host cells. Alternatively, the role for PDI may be to enzymatically activate the cell surface receptors for chlamydiae or cysteine-containing surface proteins on the infectious organisms by rearrangement of highly cross-linked by disulfide-bonds present in chlamydiae (Bavoil et al, 1984;Hatch et al, 1984;Hackstadt et al, 1985;Zhang et al, 1987;Hatch, 1996). Given the required role of PDI in chlamydial interaction with mammalian cells, future investigation will enable resolution of the mechanism of PDI in attachment and its role in the process of uptake or infectivity.…”

Alteration of chlamydia trachomatis biologic behavior in synovial membranes suppression of surface antigen production in reactive arthritis and reiter's syndrome

“…Primary antibodies. Since outer membrane components and surface antigen expression of C trachomatis change during the development cycle (23)(24)(25)(26)(27)(28), panels of primary antibodies against the L2 strain were used to detect chlamydial particles by IEM. These antibodies were 1) murine monoclonal antibody to chlamydial LPS (LPS-MAb), 2) goat polyclonal antibody to chlamydial MOMP (MOMP-PAb) (both of these antibodies were provided by Dr. Whittum-Hudson), and 3) purified goat antibodies to all EB antigens of C trachomatis (EB-Ab; Biodesign International, Kennebunk, ME).…”

Conserved features and major differences in the outer membrane protein composition of chlamydiae

“…The cell envelope of all chlamydiae studied so far is enforced by the COMC, a mesh consisting of intra-and intermolecular cysteine cross-linked proteins (Hatch, 1996). Reduction and oxidation of the disulfide bonds of proteins in the COMC during the chlamydial developmental cycle strongly influence stability, permeability and probably also infectivity of chlamydiae (Bavoil et al, 1984;Hatch et al, 1984;Betts-Hampikian and Fields, 2011). Not all OMPs are necessarily components of the COMC.…”

“…In contrast, RBs are very efficient in the acquisition of nutrients from the host cell to fuel their fast metabolic turnover during replication, but are not infectious and more fragile than EBs (Omsland et al, 2012). These differences in stability, infectivity and substrate uptake are linked not only to changes in the protein composition of the outer membrane, but also to changes in the redox state of the cysteine residues of these proteins during the progression of the developmental cycle (Hatch et al, 1984;Hatch, 1996). The importance of cysteine residues for chlamydial development is illustrated by the observation that cysteine deprivation inhibits re-differentiation of RBs to EBs (Allan et al, 1985).…”