Rapid visualization of hydrogen positions in protein neutron crystallographic structures

The 1.75 Å resolution crystallographic structure of perdeuterated rubredoxin refined against neutron data collected in just 14 h revealed 269 D atoms without ambiguity.

Protonation-state determination in proteins using high-resolution X-ray crystallography: effects of resolution and completeness

A bond-distance analysis to determine the protonation states of ionizable amino acids has been made for trypsin at 1.2 Å resolution, subtilisin at 1.26 Å resolution and lysozyme at 0.65 Å resolution. This was effective for Asp and Glu but not for His.

Inhibition of D-xylose isomerase by polyols: atomic details by joint X-ray/neutron crystallography

A joint X-ray/neutron structure of D-xylose isomerase in complex with the inhibitor sorbitol was determined at room temperature at an acidic pH of 5.9. Protonation of the O5 O atom of the sugar was directly observed in the nuclear density maps. Under acidic conditions sorbitol gains a water-mediated interaction with the enzyme active site, which may explain the increased potency of the inhibitor at low pH.