scholarly journals Conformational change of Escherichia coli initiator methionyl-tRNAfMet upon binding to methionyl-tRNA formyl transferase

2002 ◽  
Vol 30 (13) ◽  
pp. 2844-2850 ◽  
Author(s):  
C. Mayer
Keyword(s):  
Escherichia Coli ◽  
Conformational Change

scholarly journals A pH-dependent conformational change in EspA, a component of the Escherichia coli O157:H7 type III secretion system

FEBS Journal ◽  
2005 ◽  
Vol 272 (11) ◽  
pp. 2773-2783 ◽  
Author(s):  
Tomoaki Kato ◽  
Daizo Hamada ◽  
Takashi Fukui ◽  
Makoto Hayashi ◽  
Takeshi Honda ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Conformational Change ◽  
Type Iii Secretion ◽  
Type Iii Secretion System ◽  
Secretion System ◽  
Escherichia Coli O157 ◽  
Type Iii ◽  
Ph Dependent

Evidence for a conformational change in the exit site of the Escherichia coli ribosome upon tRNA binding

Biochemistry ◽  
1993 ◽  
Vol 32 (15) ◽  
pp. 4067-4072 ◽  
Author(s):  
J. Stephen Lodmell ◽  
William E. Tapprich ◽  
Walter E. Hill
Keyword(s):  
Escherichia Coli ◽  
Conformational Change ◽  
Exit Site ◽  
Trna Binding

scholarly journals An angular motion of a conserved four-helix bundle facilitates alternating access transport in the TtNapA and EcNhaA transporters

2020 ◽  
Vol 117 (50) ◽  
pp. 31850-31860
Author(s):  
Gal Masrati ◽  
Ramakanta Mondal ◽  
Abraham Rimon ◽  
Amit Kessel ◽  
Etana Padan ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Conformational Change ◽  
Thermus Thermophilus ◽  
Angular Motion ◽  
Cross Linking ◽  
Conformational Sampling ◽  
Ongoing Debate ◽  
Helix Bundle ◽  
Bias Potential ◽  
Alternating Access

There is ongoing debate regarding the mechanism through which cation/proton antiporters (CPAs), like Thermus thermophilus NapA (TtNapA) and Escherichia coli NapA (EcNhaA), alternate between their outward- and inward-facing conformations in the membrane. CPAs comprise two domains, and it is unclear whether the transition is driven by their rocking-bundle or elevator motion with respect to each other. Here we address this question using metadynamics simulations of TtNapA, where we bias conformational sampling along two axes characterizing the two proposed mechanisms: angular and translational motions, respectively. By applying the bias potential for the two axes simultaneously, as well as to the angular, but not the translational, axis alone, we manage to reproduce each of the two known states of TtNapA when starting from the opposite state, in support of the rocking-bundle mechanism as the driver of conformational change. Next, starting from the inward-facing conformation of EcNhaA, we sample what could be its long-sought-after outward-facing conformation and verify it using cross-linking experiments.

scholarly journals Impairment of the catalytic activity of Escherichia coli ribonucleic acid polymerase by a unique reaction of 4-chloro-7-nitrobenzofurazan

1979 ◽  
Vol 183 (2) ◽  
pp. 255-268 ◽  
Author(s):  
S C Bratcher ◽  
K Nitta ◽  
M J Kronman
Keyword(s):  
Escherichia Coli ◽  
Catalytic Activity ◽  
Conformational Change ◽  
Active Site ◽  
Tryptophan Fluorescence ◽  
Chain Elongation ◽  
Nitrobenzoic Acid ◽  
Unique Reaction ◽  
Calf Thymus ◽  
Partial Inactivation

Escherichia coli RNA polymerase loses 55-65% of its catalytic activity on reaction with Nbf-Cl (4-choro-7-nitrobenzofurazan). This partial inactivation was shown to be the result of specific impairment of RNA-chain elongation, since initiation of RNA chains was not altered after treatment with Nbf-Cl. The site of reaction was shown to be a unique thiol on the beta-subunit. This thiol is not accessible to reaction with 5,5′-dithiobis-(2-nitrobenzoic acid). No protection of the enzyme against reaction with Nbf-Cl could be obtained with the inhibitor rifamycin nor with calf thymus DNA, GTP or 1,10-phenanthroline, indicating that the unique thiol is probably not within the active site. The specific impairment of RNA-chain elongation thus appears to be the result of a local conformational change which leaves chain initiation unimpaired. Changes observed in the tryptophan fluorescence spectrum of the enzyme or reaction with Nbf-Cl are consistent with formation of a Meisenheimer complex of the reagent with a nucleophilic group on the enzyme near the reactive thiol. It is proposed that formation of such a complex and a subsequent conformational change renders this thiol unusually susceptible to reaction with Nbf-Cl.

Sign in / Sign up

Export Citation Format

Share Document