Histidine biosynthesis bifunctional protein HisB <p>This entry represents the histidine biosynthesis bifunctional protein HisB, which contains an N-terminal histidinol phosphate phosphatase (<db_xref db="EC" dbkey="3.1.3.15"/>) and a C-terminal imidazoleglycerol-phosphate dehydratase (<db_xref db="EC" dbkey="4.2.1.19"/>) [<cite idref="PUB00046135"/>]. HisB catalyses steps 6 and 8 of L-histidine biosynthesis. The N-terminal histidinol phosphate phosphatase domain folds into a single domain that has similarity to the haloacid dehalogenase (HAD) enzyme family, with a zinc ion stabilising the conformation of an extended loop [<cite idref="PUB00040771"/>].</p>