Synthesis of a select group of proteins by Neisseria gonorrhoeae in response to thermal stress

Abstract

We report the thermal conditions that induce the heat shock response in Neisseria gonorrhoeae. Under conditions of thermal stress, Neisseria gonorrhoeae synthesizes heat shock proteins (hsps), which differ quantitatively from conventionally studied gonococcal proteins. Gonococci accelerate the rate of synthesis of the hsps as early as 5 min after the appropriate stimulus is applied, with synthesis continuing for 30 min, as demonstrated by in vivo labeling experiments with L-[35S]methionine. Two of the gonococcal hsps are immunologically cross-reactive with the hsps of Escherichia coli, DnaK and GroEL, as demonstrated by Western blot (immunoblot) analysis. Ten hsps can be identified on two-dimensional autoradiograms of whole gonococci (total protein). Four hsps can be identified on two-dimensional autoradiograms of 1% Nlauroylsarcosine (sodium salt) (Sarkosyl)-insoluble membrane fractions. Two of the hsps from the 1% Sarkosyl-insoluble fraction are found exclusively in this fraction, suggesting that they are membrane proteins. The identification of this group of proteins will facilitate further study of the function of these proteins and provide insight into the possible role of hsps in disease pathogenesis. Growth conditions and E. coli strains. E. coli strains JM103, DH1, HB101, and Q358 were initially grown on LB 719

Characterization of the heat shock response in Brucella abortus and isolation of the genes encoding the GroE heat shock proteins

“…Heat shock proteins are synthesized when cells are exposed to elevated temperatures or to a variety of other stresses (17). The heat shock response is highly conserved and presumably allows organisms to adapt to stressful environments.…”

Alteration of gonococcal protein expression in acidic culture

“…Hsp60 homologs have been identified in OM fractions of N. gonorrhoeae (16,25) and Chlamydia trachomatis (1). Evidence that the acid-stress inducible OM protein migrating to approximately the same position as the 66-kDa marker in Fig.…”

“…We were primarily interested in differences in expression of OM proteins at the different pHs. Anaerobic, thermal, and nutrient-deprivation stress-inducible proteins have been demonstrated in OM fractions of N. gonorrhoeae (2,15,16,25). With pH stress, several proteins appeared to be upregulated at pH 5.8 (Fig.…”

“…Eucaryotic and procaryotic hsps ranging from approximately 10 to 170 kDa in size have been described previously (24). N. gonorrhoeae synthesizes both unique, stress-dependent pro-teins and widely conserved stress proteins in response to thermal, anaerobic, and nutrient stress (2,15,16,25). With acid stress, the gonococcus appears to upregulate the synthesis of hsp63 and several proteins in the same electrophoretic range as the conserved hsp70 and hsp90 families (24).…”

“…In response to anaerobic stress, indirect evidence indicates that N. gonorrhoeae synthesizes novel outer membrane (OM) proteins in vivo (3). In vitro, thermal stress induces the gonococcal homolog of major Escherichia coli heat shock proteins (hsps) DnaK and GroEL (25), and nutrient stress induces the gonococcal homolog of GroEL (hsp60), known as hsp63 in the gonococcus (16). In contrast, anaerobic stress in vitro induces three novel proteins that bear no sequence similarity to GroEL and DnaK (2).…”