This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Reprints and Permissions Copyright Information Books from ASM Press MicrobeWorld Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Mercado-Blanco, J Articles by Olivares, J Search for Related Content PubMed PubMed Citation Articles by Mercado-Blanco, J Articles by Olivares, J

research-article

Melanin production by Rhizobium meliloti GR4 is linked to nonsymbiotic plasmid pRmeGR4b: cloning, sequencing, and expression of the tyrosinase gene mepA.

Departamento de Microbiología, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Cientificas, Granada, Spain.

ABSTRACT

Melanin production by Rhizobium meliloti GR4 is linked to nonsymbiotic plasmid pRmeGR4b (140 MDa). Transfer of this plasmid to GR4-cured derivatives or to Agrobacterium tumefaciens enables these bacteria to produce melanin. Sequence analysis of a 3.5-kb PstI fragment of plasmid pRmeGR4b has revealed the presence of a open reading frame 1,481-bp that codes for a protein whose sequence shows strong homology to two conserved regions involved in copper binding in tyrosinases and hemocyanins. In vitro-coupled transcription-translation experiments showed that this open reading frame codes for a 55-kDa polypeptide. Melanin production in GR4 is not under the control of the RpoN-NifA regulatory system, unlike that in R. leguminosarum bv. phaseoli 8002. The GR4 tyrosinase gene could be expressed in Escherichia coli under the control of the lacZ promoter. For avoiding confusion with mel genes (for melibiose), a change of the name of the previously reported mel genes of R. leguminosarum bv. phaseoli and other organisms to mep genes (for melanin production) is proposed.

This article has been cited by other articles:

• Lopez-Serrano, D., Solano, F., Sanchez-Amat, A. (2007). Involvement of a novel copper chaperone in tyrosinase activity and melanin synthesis in Marinomonas mediterranea. Microbiology 153: 2241-2249 [Abstract] [Full Text]  
• Hernandez-Romero, D., Solano, F., Sanchez-Amat, A. (2005). Polyphenol Oxidase Activity Expression in Ralstonia solanacearum. Appl. Environ. Microbiol. 71: 6808-6815 [Abstract] [Full Text]  
• Guo, H., Sun, S., Finan, T. M., Xu, J. (2005). Novel DNA Sequences from Natural Strains of the Nitrogen-Fixing Symbiotic Bacterium Sinorhizobium meliloti. Appl. Environ. Microbiol. 71: 7130-7138 [Abstract] [Full Text]  
• Carreira, A., Ferreira, L. M., Loureiro, V. (2001). Brown Pigments Produced by Yarrowia lipolytica Result from Extracellular Accumulation of Homogentisic Acid. Appl. Environ. Microbiol. 67: 3463-3468 [Abstract] [Full Text]  
• Solano, F., Lucas-Elío, P., Fernández, E., Sanchez-Amat, A. (2000). Marinomonas mediterranea MMB-1 Transposon Mutagenesis: Isolation of a Multipotent Polyphenol Oxidase Mutant. J. Bacteriol. 182: 3754-3760 [Abstract] [Full Text]