The oleandomycin (OM) producer, Streptomyces antibioticus, possesses a mechanism involving two enzymes for the intracellular inactivation and extracellular reactivation of the antibiotic. Inactivation takes place by transfer of a glucose molecule from a donor (UDP-glucose) to OM, a process catalyzed by an intracellular glucosyltransferase. Glucosyltransferase activity is detectable in cell-free extracts concurrent with biosynthesis of OM. The enzyme has been purified 1,097-fold as a monomer, with a molecular mass of 57.1 kDa by a four-step procedure using three chromatographic columns. The reaction operates via a compulsory-order mechanism. This has been shown by steady-state kinetic studies using either OM or an alternative substrate (rosaramycin) and dead-end inhibitors, and isotopic exchange reactions at equilibrium. OM binds first to the enzyme, followed by UDP-glucose. A ternary complex is thus formed prior to transfer of glucose. UDP is then released, followed by the glycosylated oleandomycin (GS-OM).

CiteULike

Complore

Connotea

Del.icio.us

Digg

Reddit

Technorati

This article has been cited by other articles:

				D. N. Bolam, S. Roberts, M. R. Proctor, J. P. Turkenburg, E. J. Dodson, C. Martinez-Fleites, M. Yang, B. G. Davis, G. J. Davies, and H. J. Gilbert The crystal structure of two macrolide glycosyltransferases provides a blueprint for host cell antibiotic immunity PNAS, March 27, 2007; 104(13): 5336 - 5341. [Abstract] [Full Text] [PDF]

				D. Rodriguez, L. M. Quiros, and J. A. Salas MtmMII-mediated C-Methylation during Biosynthesis of the Antitumor Drug Mithramycin Is Essential for Biological Activity and DNA-Drug Interaction J. Biol. Chem., February 27, 2004; 279(9): 8149 - 8158. [Abstract] [Full Text] [PDF]

				A. M. Mulichak, H. C. Losey, W. Lu, Z. Wawrzak, C. T. Walsh, and R. M. Garavito Structure of the TDP-epi-vancosaminyltransferase GtfA from the chloroeremomycin biosynthetic pathway PNAS, August 5, 2003; 100(16): 9238 - 9243. [Abstract] [Full Text] [PDF]

				D. Faure The Family-3 Glycoside Hydrolases: from Housekeeping Functions to Host-Microbe Interactions Appl. Envir. Microbiol., April 1, 2002; 68(4): 1485 - 1490. [Full Text] [PDF]

				I. Aguirrezabalaga, C. Olano, N. Allende, L. Rodriguez, A. F. Braña, C. Méndez, and J. A. Salas Identification and Expression of Genes Involved in Biosynthesis of L-Oleandrose and Its Intermediate L-Olivose in the Oleandomycin Producer Streptomyces antibioticus Antimicrob. Agents Chemother., May 1, 2000; 44(5): 1266 - 1275. [Abstract] [Full Text]

				L. M. Quiros, R. J. Carbajo, A. F. Brana, and J. A. Salas Glycosylation of Macrolide Antibiotics. PURIFICATION AND KINETIC STUDIES OF A MACROLIDE GLYCOSYLTRANSFERASE FROM STREPTOMYCES ANTIBIOTICUS J. Biol. Chem., April 14, 2000; 275(16): 11713 - 11720. [Abstract] [Full Text] [PDF]