claim: protonation states in sars-cov-2 main protease mapped by blast crystallography
evidence_1: this structure highlights the ability of neutron protein crystallography for experimentally determining protonation states at near- physiological temperature  the critical information for structure-assisted and computational drug design.", "a long-standing question in the field has been what the protonation states of the ionizable residues in the substrate-binding active site cavity are.", "the neutron structure also identified the protonation states of other amino acid residues, mapping electrical charges and intricate hydrogen bonding networks in the sars-cov-2 3cl mpro active site cavity and dimer interface.", 
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  "here, we present the room- temperature neutron structure of 3cl mpro from sars-cov-2, which allows direct determination of hydrogen atom positions and, hence, protonation states.")