 the millisecond time scale needed 
 for molecular dynamics simulations 
 to approach the quantitative study of protein folding is not yet routine . 
 
 one approach to extend the simulation time scale is to perform long 
 simulations on specialized and expensive supercomputers such as anton . 
 
 ideally , however , folding simulations would be more economical while 
 retaining reasonable accuracy , and provide feedback on structure , 
 stability and function rapidly enough if partnered directly with experiment . 
 
 approaches to this problem typically involve varied compromises between 
 accuracy , precision , and cost ; the goal here is to address whether 
 simple implicit solvent models have become sufficiently accurate for 
 their weaknesses to be offset by their ability to rapidly provide 
 much more precise conformational data as compared to explicit solvent . 
 we demonstrate that our recently developed physics - based model performs 
 well on this challenge , enabling accurate all - atom simulated folding 
 for 16 of 17 proteins with a variety of sizes , secondary structure , 
 and topologies . 
 the simulations were carried out using the amber software 
 on inexpensive gpus , providing 1 s / day per gpu , and 
 > 2.5 ms data presented here . 
 we also show that native conformations 
 are preferred over misfolded structures for 14 of the 17 proteins . 
 
 for the other 3 , misfolded structures are thermodynamically preferred , 
 suggesting opportunities for further improvement . 
Supplementary Material