Reactions constituting cluster 1 and nearby clusters from wild-type and lpdA mutant of E. coli . Clusters 3, 6, 9, 12, 18 and 29 are under direct influence of cluster 1. Each box contains information on reactions in the order of their respective TMI values for each cluster (see Additional file 1 for details). Numbers next to each cluster number are the calculated average essentiality of reactions in the cluster for the wild-type and lpdA mutant in order; the higher the essentiality value is, the more essential the reaction is. Reactions in red are the representative reactions. Parenthesis next to the enzyme name shows the name of submetabolism, in which the enzyme is involved, and substrates for O-succinylhomoserine lyase (cluster 1, L-cysteine), uridylate kinase (cluster 29, dUMP) and purine-nucleoside phosphorylase (cluster 29, adenosine). Cluster 41 influencing cluster 1 contains 14 reactions, associated with: glycolysis/gluconeogenesis, histidine metabolism, membrane lipid metabolism, and tyrosine, tryptophan, and phenylalanine metabolism. Its representative reactions are prephenate dehydrogenase and tyrosine transaminase, both involved in tyrosine, tryptophan, and phenylalanine metabolism.