The critical structural role of a highly conserved histidine residue in group II amino acid decarboxylases.
Glutamate decarboxylase is a pyridoxal 5'-phosphate (PLP)-dependent enzyme, belonging to the subset of PLP-dependent decarboxylases classified as group II. Site-directed mutagenesis of Escherichia coli glutamate decarboxylase, combined with analysis of the crystal structure, shows that a histidine residue buried in the protein core is critical for correct folding. This histidine is strictly conserved in the PF00282 PFAM family, which includes the group II decarboxylases. A similar role is proposed for residue Ser269, also highly conserved in this group of enzymes, as it provides one of the interactions stabilising His241.
Capitani
Guido
G
Biochemisches Institut der Universität Zürich, Winterthurerstrasse 190, 8057 Zürich, Switzerland.
Tramonti
Angela
A
Bossa
Francesco
F
Grütter
Markus G
MG
De Biase
Daniela
D
D000595:Amino Acid Sequence; D019943:Amino Acid Substitution; D017124:Conserved Sequence; D029968:Escherichia coli Proteins / Q000737:chemistry; D005968:Glutamate Decarboxylase / Q000737:chemistry* / Q000235:genetics; D006639:Histidine; D015394:Molecular Structure; D016297:Mutagenesis, Site-Directed; D011487:Protein Conformation; D012694:Serine
D029968:Escherichia coli Proteins; D012694:Serine; D006639:Histidine; D005968:Glutamate Decarboxylase