title: Relevance of glycine and cysteine residues as well as N- and C-terminals for the activity of protein histidine phosphatase.
abstract: There is increasing evidence that reversible phosphorylation of histidine residues regulates numerous important cellular processes. The first protein histidine phosphatase (PHP) from vertebrates was discovered just recently. Here, we report on amino acids and domains essential for activity of PHP. Point mutations of conserved residues and deletions of the N- and C-termini of PHP were analyzed using [(32)P-his]ATP-citrate lyase as a substrate. Individual or joint replacement of all cysteine residues by alanine did not affect PHP activity. Deletion of 9 N-terminal amino acids resulted in inactive PHP. Furthermore, only 4 C-terminal residues could be deleted without losing PHP activity. Single or multiple mutations of the glycine-rich domain (Gly(75), Gly(77)) of a putative nucleotide binding site of PHP (GxGxxG/S) caused inactivation of PHP. Wildtype PHP could be labeled with [alpha-(32)P]ATP. Such radiolabeling was not detectable for catalytically inactive PHP-G75A and PHP-G77A. These data suggest further studies on the interaction between PHP and ATP.
authors.affiliation: Institut für Pharmazeutische und Medizinische Chemie, D-48149 Muenster, Germany. k.secretary@uni-muenster.de
authors.forename: Susanne
authors.initials: S
authors.lastname: Klumpp
authors.forename: Nien Tze
authors.initials: NT
authors.lastname: Ma
authors.forename: Nicole
authors.initials: N
authors.lastname: Bäumer
authors.forename: Gunther
authors.initials: G
authors.lastname: Bechmann
authors.forename: Josef
authors.initials: J
authors.lastname: Krieglstein
mesh_terms: D000595:Amino Acid Sequence; D003001:Cloning, Molecular; D003545:Cysteine / Q000235:genetics / Q000378:metabolism; D004926:Escherichia coli / Q000201:enzymology; D005998:Glycine / Q000235:genetics / Q000378:metabolism; D006801:Humans; D016297:Mutagenesis, Site-Directed; D010744:Phosphoric Monoester Hydrolases / Q000235:genetics / Q000378:metabolism*
chemical_list: C504019:PHPT1 protein, human; D010744:Phosphoric Monoester Hydrolases; D003545:Cysteine; D005998:Glycine