Fluorescence and 19F NMR evidence that phenylalanine, 3-L-fluorophenylalanine and 4-L-fluorophenylalanine bind to the L-leucine specific receptor of Escherichia coli.
The binding capacity of the L-leucine receptor from Escherichia coli was measured with L-phenylalanine and 4-fluoro-L-phenylalanine as substrates by fluorescence. The apparent dissociation constants (KD) for L-leucine, L-phenylalanine, and 4-fluoro-L-phenylalanine are 0.40, 0.18, and 0.26 respectively. 19F NMR data show protein-induced shifts for the 4-fluoro-L-phenylalanine peak and 3-fluoro-L-phenylalanine when receptor is present. Evidence points to the binding of only the L-isomers of these fluorine analogs.
Luck
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LA
Department of Chemistry, Clarkson University, Potsdam, New York 13699, USA. luckla@clarkson.edu
Johnson
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C
D004926:Escherichia coli / Q000737:chemistry; D005462:Fluorine Radioisotopes; D007536:Isomerism; D019906:Nuclear Magnetic Resonance, Biomolecular; D010649:Phenylalanine / Q000737:chemistry / Q000378:metabolism*; D011485:Protein Binding; D017459:Receptors, Amino Acid / Q000378:metabolism*; D013050:Spectrometry, Fluorescence; D010135:p-Fluorophenylalanine / Q000737:chemistry / Q000378:metabolism
D005462:Fluorine Radioisotopes; D017459:Receptors, Amino Acid; C034181:leucine receptor; D010649:Phenylalanine; D010135:p-Fluorophenylalanine