1W4J

Peripheral-subunit binding domains from mesophilic, thermophilic, and hyperthermophilic bacteria fold by ultrafast, apparently two-state transitions

Summary for 1W4J

• Entry DOI: 10.2210/pdb1w4j/pdb
• Related: 1W4E 1W4F 1W4H 1W4I 1W4K
• Descriptor: PYRUVATE DEHYDROGENASE E2 (1 entity in total)
• Functional Keywords: peripheral-subunit binding domain, ultrafast folding, homologues, transferase
• Biological source: PYROBACULUM AEROPHILUM
• Total number of polymer chains: 1
• Total formula weight: 5260.01

Authors

Ferguson, N.,Sharpe, T.D.,Schartau, P.J.,Allen, M.D.,Johnson, C.M.,Sato, S.,Fersht, A.R. (deposition date: 2004-07-23, release date: 2005-07-20, Last modification date: 2024-05-15)

Primary citation

Ferguson, N.,Sharpe, T.D.,Schartau, P.J.,Sato, S.,Allen, M.D.,Johnson, C.M.,Rutherford, T.J.,Fersht, A.R.
Ultra-fast barrier-limited folding in the peripheral subunit-binding domain family.
J. Mol. Biol., 353:427-446, 2005

PubMed Abstract: We have determined the solution structures, equilibrium properties and ultra-fast folding kinetics for three bacterial homologues of the peripheral subunit-binding domain (PSBD) family. The mesophilic homologue, BBL, was less stable than the thermophilic and hyper-thermophilic variants (E3BD and POB, respectively). The broad unfolding transitions of each PSBD, when probed by different techniques, were essentially superimposable, consistent with co-operative denaturation. Temperature-jump and continuous-flow fluorescence methods were used to measure the folding kinetics for E3BD, POB and BBL. E3BD folded fairly rapidly at 298K (folding half-time approximately 25 micros) and BBL and POB folded even faster (folding half-times approximately 3-5 micros). The variations in equilibrium and kinetic behaviour observed for the PSBD family resembles that of the homeodomain family, where the folding pattern changes from apparent two-state transitions to multi-state kinetics as the denatured state becomes more structured. The faster folding of POB may be a consequence of its higher propensity to form helical structure in the region corresponding to the folding nucleus of E3BD. The ultra-fast folding of BBL appears to be a consequence of residual structure in the denatured ensemble, as with engrailed homeodomain. We discuss issues concerning "one-state", downhill folding, and find no evidence for, and strong evidence against, it occurring in these PSBDs. The shorter construct used previously for BBL was destabilized significantly and the stability further perturbed by the introduction of fluorescent probes. Thermal titrations for 11 side-chains scattered around the protein, when probed by (13)C-NMR experiments, could be fit globally to a common co-operative transition.

PubMed: 16168437
DOI: 10.1016/j.jmb.2005.08.031

Experimental method

SOLUTION NMR