Lincomycin Biosynthesis Involves a Tyrosine Hydroxylating Heme Protein of an Unusual Enzyme FamilyReportar como inadecuado




Lincomycin Biosynthesis Involves a Tyrosine Hydroxylating Heme Protein of an Unusual Enzyme Family - Descarga este documento en PDF. Documentación en PDF para descargar gratis. Disponible también para leer online.

The gene lmbB2 of the lincomycin biosynthetic gene cluster of Streptomyces lincolnensis ATCC 25466 was shown to code for an unusual tyrosine hydroxylating enzyme involved in the biosynthetic pathway of this clinically important antibiotic. LmbB2 was expressed in Escherichia coli, purified near to homogeneity and shown to convert tyrosine to 3,4-dihydroxyphenylalanine DOPA. In contrast to the well-known tyrosine hydroxylases EC 1.14.16.2 and tyrosinases EC 1.14.18.1, LmbB2 was identified as a heme protein. Mass spectrometry and Soret band-excited Raman spectroscopy of LmbB2 showed that LmbB2 contains heme b as prosthetic group. The CO-reduced differential absorption spectra of LmbB2 showed that the coordination of Fe was different from that of cytochrome P450 enzymes. LmbB2 exhibits sequence similarity to Orf13 of the anthramycin biosynthetic gene cluster, which has recently been classified as a heme peroxidase. Tyrosine hydroxylating activity of LmbB2 yielding DOPA in the presence of 6R-5,6,7,8-tetrahydro-L-biopterin BH4 was also observed. Reaction mechanism of this unique heme peroxidases family is discussed. Also, tyrosine hydroxylation was confirmed as the first step of the amino acid branch of the lincomycin biosynthesis.



Autor: Jitka Novotna , Jana Olsovska, Petr Novak, Peter Mojzes, Radka Chaloupkova, Zdenek Kamenik, Jaroslav Spizek, Eva Kutejova, Market

Fuente: http://plos.srce.hr/



DESCARGAR PDF




Documentos relacionados