Polymer production by Klebsiella pneumoniae 4-hydroxyphenylacetic acid hydroxylase genes cloned in Escherichia coli.
The expression of Klebsiella pneumoniae hpaA and hpaH genes, which code for 4-hydroxyphenylacetic acid hydroxylase in Escherichia coli K-12 derivative strains, is associated with the production of a dark brown pigment in the cultures. This pigment has been identified as a polymer which shows several of the characteristics reported for microbial melanins and results from the oxidative activity of 4-hydroxyphenylacetic acid hydroxylase on some dihydroxylated compounds to form o-quinones. A dibenzoquinone is formed from the oxidation of different mono- or dihydroxylated aromatic compounds by the enzyme prior to polymerization. We report a hydroxylase activity, other than tyrosinase, that is associated with the synthesis of a bacterial melanin.
Departamento de Microbiología (Patología Animal I), Facultad de Veterinaria, Universidad Complutense, Madrid, Spain.
A
A
Gibello
E
E
Ferrer
J
J
Sanz
M
M
Martin
D003001:Cloning, Molecular; D004926:Escherichia coli / Q000235:genetics* / Q000378:metabolism / Q000648:ultrastructure; D015964:Gene Expression Regulation, Bacterial; D007711:Klebsiella pneumoniae / Q000235:genetics* / Q000378:metabolism; D008543:Melanins / Q000378:metabolism; D008854:Microscopy, Electron; D006899:Mixed Function Oxygenases / Q000235:genetics*; D011108:Polymers / Q000378:metabolism*
D008543:Melanins; D011108:Polymers; D006899:Mixed Function Oxygenases; C026252:4-hydroxyphenylacetate 3-monooxygenase