An essential methionine residue involved in substrate binding by phosphofructokinases.
An alignment of all PPi-dependent phosphofructokinases and all allosteric ATP-dependent PFKs shows relatively few residues that are fully conserved. One residue that is conserved is a methionine residue that appears from the crystal structure of Escherichia coli PFK to be interacting with fructose 6-P. Very conservative substitutions for this methionine with leucine or isoleucine by site-directed mutagenesis of E. coli ATP-PFK and Entamoeba histolytica PPi-PFK produced profound decreases either in the apparent affinity for fructose 6-P or in maximal velocity, or both. Methionine provides a highly specific interaction with fructose 6-P for binding and for transition state stabilization.
Wang
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Department of Microbiology, Chicago Medical School, Illinois 60064, USA.
Deng
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Kemp
R G
RG
D000494:Allosteric Regulation; D000818:Animals; D001665:Binding Sites; D017124:Conserved Sequence; D004747:Entamoeba / Q000201:enzymology*; D004926:Escherichia coli / Q000201:enzymology*; D008715:Methionine; D009154:Mutation; D010732:Phosphofructokinase-1 / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D013379:Substrate Specificity
D008715:Methionine; D010732:Phosphofructokinase-1