Characterization and identification of early proteins in Chlamydia trachomatis serovar L2 by two-dimensional gel electrophoresis

Abstract

The synthesis of early proteins from Chlamydia trachomatis serovar L2 was analyzed by two-dimensional gel electrophoresis. By pulse-label experiments, the synthesis of seven proteins was observed at 2 to 8 h postinfection before the major outer membrane protein was detected at 8 to 10 h after infection. The early proteins were synthesized throughout the 30-h period investigated, but the synthesis of three proteins of 75, 62, and 45 kilodaltons decreased from 26 to 30 h postinfection. Pulse-chase analysis showed that the signals from the same three proteins declined 26 to 30 h after infection. Three of the early proteins were identified as the S1 ribosomal protein, the GroEL-like protein, and DnaK-like protein, respectively.

The immunobiology and immunopathology of chlamydial infections

“…Human and E. coli hsps function as chaperonins, involved in the ATP-dependent renaturation and refolding of proteins damaged by proteolytic, heat or oxidative stress, as well as targeting proteins or peptide fragments to biological membranes (66). The chlamydial hsp60 and hsp70 are early proteins, expressed 2 to 26 h postinfection (96). Chlamydia1 hsp70, like human hsp70, may confer partial resistance to the cytotoxic effects of TNFa (74, 89j.…”

The intracellular life of Chlamydia psittaci: how do the bacteria interact with the host cell?

“…Other components are also thought to be important for the interaction with the host cell. For example, early in the developmental cycle, bacterial heat shock proteins of the 60-, 70and 110-kDa families are synthesized [49,52,60,83,116]. This could suggest that chlamydiae begin to modify the normal activity of the host cells soon after entry, ensuring themselves a less stressful environment.…”

“…Chlamydiae are also capable of a¡ecting RNA and DNA [35,58]. Interestingly, RNA and some protein synthesis appears to be developmental cycle stage speci¢c [18,52,73]. It has been observed that when cells are infected with C. psittaci, the rates of synthesis of protein, RNA and DNA in the infected cells never exceed the rates observed with non- [27] (c) Large CRP doublet or EnvB Major structural envelope protein Functional equivalent of peptidoglycan( ?)…”

“…Chlamydial growth stops as ATP and reducing power diminish, inducing a decrease of metabolic activities, oxidation of free sulfhydryls into disul¢des (that leads to crosslinking of the cysteine-rich proteins), closing of outer membrane pores, and outer membrane rigidi¢cation as RBs transform to EBs [6,14,75]. In addition, it has been shown that di¡erent proteins are expressed at di¡erent times during the chlamydial cycle [18,36,39,52,73].…”

Redirection of Host Vesicle Trafficking Pathways by Intracellular Parasites

“…One of the initial events in chlamydial infection is the expression of a chlamydial gene product(s) that effectively isolates the inclusion from the endosomal/lysosomal pathway and initiates fusion competence with sphingomyelin‐containing exocytic vesicles[60]. Although extracellular EBs do not exhibit transcriptional activity, chlamydiae initiate protein synthesis relatively soon after endocytosis[61,62]. Within the first 2 h post‐internalization, EBs become committed to progression through the developmental cycle by processes that require de novo chlamydial transcription and translation.…”