4P3R

Cryogenic WT DHFR, time-averaged ensemble

Summary for 4P3R

• Entry DOI: 10.2210/pdb4p3r/pdb
• Related: 4KJK 4P3R
• Descriptor: Dihydrofolate reductase, FOLIC ACID, NADP NICOTINAMIDE-ADENINE-DINUCLEOTIDE PHOSPHATE, ... (4 entities in total)
• Functional Keywords: rossmann fold, oxidoreductase
• Biological source: Escherichia coli
• Total number of polymer chains: 1
• Total formula weight: 19204.14

Authors

Keedy, D.A.,van den Bedem, H.,Fraser, J.S. (deposition date: 2014-03-10, release date: 2014-05-14, Last modification date: 2023-12-27)

Primary citation

Keedy, D.A.,van den Bedem, H.,Sivak, D.A.,Petsko, G.A.,Ringe, D.,Wilson, M.A.,Fraser, J.S.
Crystal Cryocooling Distorts Conformational Heterogeneity in a Model Michaelis Complex of DHFR.
Structure, 22:899-910, 2014

PubMed Abstract: Most macromolecular X-ray structures are determined from cryocooled crystals, but it is unclear whether cryocooling distorts functionally relevant flexibility. Here we compare independently acquired pairs of high-resolution data sets of a model Michaelis complex of dihydrofolate reductase (DHFR), collected by separate groups at both room and cryogenic temperatures. These data sets allow us to isolate the differences between experimental procedures and between temperatures. Our analyses of multiconformer models and time-averaged ensembles suggest that cryocooling suppresses and otherwise modifies side-chain and main-chain conformational heterogeneity, quenching dynamic contact networks. Despite some idiosyncratic differences, most changes from room temperature to cryogenic temperature are conserved and likely reflect temperature-dependent solvent remodeling. Both cryogenic data sets point to additional conformations not evident in the corresponding room temperature data sets, suggesting that cryocooling does not merely trap preexisting conformational heterogeneity. Our results demonstrate that crystal cryocooling consistently distorts the energy landscape of DHFR, a paragon for understanding functional protein dynamics.

PubMed: 24882744
DOI: 10.1016/j.str.2014.04.016

Experimental method

X-RAY DIFFRACTION (1.15 Å)