Open AccessCharacterization of 4‐hydroxyphenylpyruvate dioxygenase
Author(s) -
RÜETSCHI Ulla,
ODELHÖG Birgit,
LINDSTEDT Sven,
BARROSSÖDERLING Jane,
PERSSON Bengt,
JÖRNVALL Hans
Publication year - 1992
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1111/j.1432-1033.1992.tb16800.x
Subject(s) - hydroxylamine , chemistry , peptide sequence , biochemistry , protein secondary structure , protein primary structure , residue (chemistry) , protein subunit , enzyme , protein structure , cleavage (geology) , stereochemistry , biology , gene , paleontology , fracture (geology)
The primary structure of Pseudomonas 4‐hydroxyphenylpyruvate dioxygenase was determined. Sequence degradation of the intact protein and of peptides from three different digests of the carboxymethylated protein established a 357‐residue polypeptide chain with a free α ‐amino group. Hydroxylamine cleavage at a single Asn‐Gly sequence was useful. Comparisons with known structures in data banks revealed no close relationship with other characterized proteins. The human enzyme has a related composition, suggesting that also the eukaryotic form belongs to this protein type, but with a blocked N‐terminus like in many other eukaryotic intracellular proteins. Secondary structure predictions suggest an α / β mixed structure, fairly typical of globular proteins, without long segments of hydrophobicity or charge, although a region in the middle of the C‐terminal third of the subunit appears to have the most extreme properties. A ferric centre, correlating with enzyme activity and absorbance at 595 nm, has previously been assigned to tyrosinate coordination. The Tyr and His distributions, and the position of a single Cys residue, all suggest a few likely sites, outside the C‐terminal segment, for this centre.