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.

• MeSH
• Anti-Bacterial Agents biosynthesis   MeSH
• Bacterial Proteins genetics   metabolism   MeSH
• Circular Dichroism MeSH
• Dihydroxyphenylalanine metabolism   MeSH
• Escherichia coli enzymology   genetics   MeSH
• Gene Expression MeSH
• Heme chemistry   metabolism   MeSH
• Hemeproteins genetics   metabolism   MeSH
• Hydroxylation MeSH
• Lincomycin biosynthesis   MeSH
• Multigene Family MeSH
• Recombinant Proteins genetics   metabolism   MeSH
• Streptomyces enzymology   genetics   MeSH
• Tyrosine 3-Monooxygenase genetics   metabolism   MeSH
• Tyrosine metabolism   MeSH
• Chromatography, High Pressure Liquid MeSH
• Iron chemistry   metabolism   MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• Anti-Bacterial Agents MeSH
• Bacterial Proteins MeSH
• Dihydroxyphenylalanine MeSH
• Heme MeSH
• Hemeproteins MeSH
• Lincomycin MeSH
• Recombinant Proteins MeSH
• Tyrosine 3-Monooxygenase MeSH
• Tyrosine MeSH
• Iron MeSH