The Single-Ring Thermoanaerobacter brockii Chaperonin 60 (Tbr-EL7) Dimerizes to Tbr-EL14.cntdot.Tbr-ES7 under Protein Folding Conditions

Todd, Matthew J.; Walke, Stefan; Lorimer, George H.; Truscott, Kaye N.; Scopes, Robert K.

doi:10.1021/bi00045a038

“…There may be exceptions to the rule, although, the Thermoanaerobacter brockii thermosome, which has initially been believed to be a genuine single-ring species (7), has been demonstrated to assemble into a double-ring structure during its functional cycle (8). Therefore, the Haloarcula marismortui thermosome, which assembles into a single-ring species variably comprising between 8 and 10 subunits (9), as well as the three single-ring mutants of GroEL (SR-T522I, SR-D115N, and SR-A399T), which have been shown to rescue GroEL-deficient E. coli (10), may well form double-ring structures in the presence of nucleotide.…”

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confidence: 99%

Identification of a Major Inter-ring Coupling Step in the GroEL Reaction Cycle

Poso

¹

,

Clarke²,

Burston³

2004

Journal of Biological Chemistry

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It has been shown previously that the double-ring structure of GroEL can be converted to a single-ring species by site-directed amino acid replacements at the ring interface and that the resultant molecule retains many of the crucial chaperonin properties; it is structurally stable, hydrolytically active, and can bind both the co-chaperonin, GroES, and unfolded substrate proteins. By comparing the behavior of the double-and single-ring structures in response to nucleotide binding and hydrolysis, we elucidate steps in the ATP-driven reaction cycle at which there is conformational coupling between the rings. Remarkably, the parting of the rings has little effect either on the thermodynamic properties of ATP binding or on the ATP-induced conformational changes prior to hydrolysis. However, there is a marked effect on the rate-limiting process in the steady-state cycle; a step that is coincident with bond cleavage in ATP. The effect of the ring-ring interaction is to increase its activation enthalpy from 42.0 to 94.2 kJ/mol. These results show that the major conformational coupling step, where structural rearrangements in one ring are propagated to the other, is the slowest process the ATPase cycle of GroEL.

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“…Chaperonin from Thermus thermophilus (Tcpn60 14 14 was additionally included in the solution described above, hybrid chaperonins GroEL 7 ⅐Tcpn60 7 and GroEL 7 ⅐ Tcpn60 7 ⅐Tcpn10 7 were formed rapidly (<20 s) at 37°C. The hybrid was also formed from Tcpn60 14 and GroEL 14 but not from a mutant GroEL 14 lacking ATPase activity.…”

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confidence: 99%

“…The hybrid was also formed from Tcpn60 14 and GroEL 14 but not from a mutant GroEL 14 lacking ATPase activity. The hybrid formation was saturated at ϳ300 M ATP and ϳ300 mM K ؉ .…”

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confidence: 99%

“…Once formed, the hybrid chaperonins were stable, and the parent chaperonins were not regenerated from the isolated hybrids under the same conditions in which the hybrids had been formed. Only under conditions in which GroEL in the hybrids was selectively destroyed, such as incubation at 70°C, Thermus chaperonin, but not GroEL 14 , was regenerated from the hybrid. Therefore, the split reaction may not be an obligatory event repeated in each turnover of the chaperonin functional cycles but an event that occurs only when chaperonin is first exposed to ATP/K ؉ .…”

mentioning

confidence: 99%

“…GroEL 14 is an Escherichia coli chaperonin that facilitates the proper folding of proteins in an ATP-dependent manner (1-3). As determined by x-ray crystallography, GroEL 14 seems to be a hollow cylinder of 14 identical 57-kDa subunits consisting of 2 heptamer rings stacked back-to-back with a dyad symmetry (GroEL 7 ⅐GroEL 7 ) (4).…”

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confidence: 99%

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ATP-, K+-dependent Heptamer Exchange Reaction Produces Hybrids between GroEL and Chaperonin from Thermus thermophilus

Taguchi

¹

,

Amada

²

,

Murai

³

et al. 1997

Journal of Biological Chemistry

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Chaperonin from Thermus thermophilus (Tcpn60 14 ⅐ Tcpn10 7 ) splits at the plane between two Tcpn60 7 rings into two parts in a solution containing ATP and K ؉ (Ishii, N., Taguchi, H., Sasabe, H., and Yoshida, M. (1995) FEBS Lett. 362, 121-125). When Escherichia coli GroEL 14 was additionally included in the solution described above, hybrid chaperonins GroEL 7 ⅐Tcpn60 7 and GroEL 7 ⅐ Tcpn60 7 ⅐Tcpn10 7 were formed rapidly (<20 s) at 37°C. The hybrid was also formed from Tcpn60 14 and GroEL 14 but not from a mutant GroEL 14 lacking ATPase activity. The hybrid formation was saturated at ϳ300 M ATP and ϳ300 mM K ؉ . These results imply that GroEL 14 also splits and undergoes a heptamer exchange reaction with Thermus chaperonin under nearly physiological conditions. Similar to parent chaperonins, the isolated hybrid chaperonins exhibited ATPase activity that was susceptible to inhibition by Tcpn10 7 or GroES 7 and mediated folding of other proteins. Once formed, the hybrid chaperonins were stable, and the parent chaperonins were not regenerated from the isolated hybrids under the same conditions in which the hybrids had been formed. Only under conditions in which GroEL in the hybrids was selectively destroyed, such as incubation at 70°C, Thermus chaperonin, but not GroEL 14 , was regenerated from the hybrid. Therefore, the split reaction may not be an obligatory event repeated in each turnover of the chaperonin functional cycles but an event that occurs only when chaperonin is first exposed to ATP/K ؉ .

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Thermoanaerobacter

Onyenwoke

¹

,

Wiegel

²

2015

Bergey's Manual of Systematics of Archaea and Bacteria

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Ther.mo.an.ae.ro.bac'ter. Gr. adj. thermos hot; Gr. pref. an not; Gr. n. aer air; M.L. bacter masc. equivalent of Gr. neut. dim. n. bakterion rod staff; N.L. masc. n. Thermoanaerobacter rod which grows in the absence of air at elevated temperatures. Firmicutes / “Clostridia” / Thermoanaerobacterales / Thermoanaerobacteraceae / Thermoanaerobacter All species are obligately anaerobic thermophiles and have a Gram‐positive cell wall , i.e., although the Gram‐stain reaction varies among the individual species and even within strains from the same species, they have a Gram‐positive cell‐wall structure. Most species exhibit a sluggish motility and a peritrichous arrangement of 2–6 flagella (retarded peritrichous flagellation). Cells are rod shaped and occur in various arrangements that vary by species. Many of the Thermoanaerobacter species form pleomorphic cells during the late exponential and stationary growth phases assembling through nonsymmetric cell division chains of alternating rod‐shaped and coccoid cells. Other types of pleomorphic rods are formed, presumably through weakening of the cell wall by lysozyme‐like enzymes that are the remnants of the sporulation process ( Figure 1). Growth temperature optima range from 55–75 °C, with growth ranges of 35–78 ° C and a temperature span over 35 ° C . The pH for growth ranges from pH 25C 4 . 0–9 . 9 , with a pH optimum of 5.8–8.5. Several species also exhibit a wide pH optimum of about 3 units without a sharp peak. All species are able to grow organoheterotrophically using various fermentation pathways including the homoacetogenic or Wood–Ljungdahl pathway, or using inorganic electron acceptors (e.g., Thermoanaerobacter sulfuriphilus using S 0 as an electron acceptor and lactate as an electron donor and carbon source). Some Thermoanaerobacter strains are also able to grow chemolithoheterotrophically by coupling H 2 oxidation to growth (Fardeau et al., 1994). Furthermore, others are facultative chemolithoautotrophs , growing with H 2 + CO 2 (such as Thermoanaerobacter kivui ) or Fe(III) + H 2 + CO 2 (such as Thermoanaerobacter siderophilus ). Generally, typical fermentation products from hexoses are ethanol, acetate, lactate, H 2 , and CO 2 . DNA G + C content ( mol %): 30–39. Type species : Thermoanaerobacter ethanolicus Wiegel and Ljungdahl 1982, 384 VP (Effective publication: Wiegel and Ljungdahl 1981, 348.).

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The Single-Ring Thermoanaerobacter brockii Chaperonin 60 (Tbr-EL7) Dimerizes to Tbr-EL14.cntdot.Tbr-ES7 under Protein Folding Conditions

Cited by 24 publications

References 28 publications

Identification of a Major Inter-ring Coupling Step in the GroEL Reaction Cycle

Identification of a Major Inter-ring Coupling Step in the GroEL Reaction Cycle

ATP-, K+-dependent Heptamer Exchange Reaction Produces Hybrids between GroEL and Chaperonin from Thermus thermophilus

Thermoanaerobacter

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