User:Waltonph1/sandbox

= Histidine brace = The histidine brace is a type of active site found in many enzymes. The unit is widespread in biology, occurring in enzymes that act as powerful monooxygenases, for example, lytic polysaccharide monooxygenases and particulate methane monooxygenases. The histidine brace consists of two histidine amino acids within a protein structure, one of which is always at the N-terminus of the protein. Often, the N-terminal histidine is methylated on the remote nitrogen atom of the imidazole ring. The resulting arrangement of histidines coordinates to a metal ion, typically a copper, in which the nitrogen atoms of the histidine side chains along with the NH2 amino terminus form coordinative bonds to the copper ion. The overall structure of the nitrogen atoms around the metal ion is T-shaped, leaving a vacant coordination site on the metal, at which other ligands can coordinate, such as H2O or O2.

The histidine brace was named in 2011 by Paul Walton from the University of York, UK.