Biosynthesis of cytochalasans. XI. New results on the incorporation of phenylalanine into cytochalasin D by Zygosporium masonii [1].
Incorporation of L-[2-2H]phenyl-[2-2H]alanine and L-phenyl-[2-13C, 15N]alanine into cytochalasin D by Zygosporium masonii involved the complete loss of both the alpha-2H- and the alpha-15N-atom. Incorporation of a mixture of L-phenyl-[15N]alanine and L-[U-14C]phenylalanine into cytochalasin D and protein amino acids (phenylalanine, leucine, isoleucine) was accompanied by a substantial loss of 15N with respect to 14C. These effects are attributed to rapid exchange reactions taking place while L-phenylalanine is part of the intracellular pool of amino acids. In addition, the medium- and concentration-dependent incorporation of the carbon skeleton of exogeneous D-phenylalanine into cytochalasin D is reported. In a peptone-based complex medium, D-phenyl-alanine is poorly incorporated. Throughout the whole concentration range (0-250 mg/l), the incorporation rates are less than 10% of those of L-phenylalanine. In a minimal medium containing NH4NO3 as nitrogen source however, D-phenylalanine is preferred over the natural enantiomer by a factor of 1.28 up to 6.78, depending on the concentrations of exogeneous D- and L-phenylalanine. These effects are attributed to the medium-dependent activities of different amino acid transport systems responsible for the uptake of D- and L-phenylalanine in Z. masonii.
Hädener
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A
Institut für Organische Chemie der Universität Basel.
Roth
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P
Tamm
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C
D015638:Cytochalasin D; D003572:Cytochalasins / Q000096:biosynthesis*; D003903:Deuterium; D005947:Glucose / Q000378:metabolism; D007700:Kinetics; D009682:Magnetic Resonance Spectroscopy; D003904:Mitosporic Fungi / Q000201:enzymology* / Q000254:growth & development; D010649:Phenylalanine / Q000378:metabolism*
D003572:Cytochalasins; D015638:Cytochalasin D; D010649:Phenylalanine; D003903:Deuterium; D005947:Glucose