title: Restricted distribution of the butyrate kinase pathway among butyrate-producing bacteria from the human colon.
abstract: The final steps in butyrate synthesis by anaerobic bacteria can occur via butyrate kinase and phosphotransbutyrylase or via butyryl-coenzyme A (CoA):acetate CoA-transferase. Degenerate PCR and enzymatic assays were used to assess the presence of butyrate kinase among 38 anaerobic butyrate-producing bacterial isolates from human feces that represent three different clostridial clusters (IV, XIVa, and XVI). Only four strains were found to possess detectable butyrate kinase activity. These were also the only strains to give PCR products (verifiable by sequencing) with degenerate primer pairs designed within the butyrate kinase gene or between the linked butyrate kinase/phosphotransbutyrylase genes. Further analysis of the butyrate kinase/phosphotransbutyrylase genes of one isolate, L2-50, revealed similar organization to that described previously from different groups of clostridia, along with differences in flanking sequences and phylogenetic relationships. Butyryl-CoA:acetate CoA-transferase activity was detected in all 38 strains examined, suggesting that it, rather than butyrate kinase, provides the dominant route for butyrate formation in the human colonic ecosystem that contains a constantly high concentration of acetate.
authors.affiliation: Division of Gut Microbiology and Immunology, Rowett Research Institute, Bucksburn, Aberdeen AB21 9SB, UK. p.louis@rowett.ac.uk
authors.forename: Petra
authors.initials: P
authors.lastname: Louis
authors.forename: Sylvia H
authors.initials: SH
authors.lastname: Duncan
authors.forename: Sheila I
authors.initials: SI
authors.lastname: McCrae
authors.forename: Jacqueline
authors.initials: J
authors.lastname: Millar
authors.forename: Michelle S
authors.initials: MS
authors.lastname: Jackson
authors.forename: Harry J
authors.initials: HJ
authors.lastname: Flint
mesh_terms: D001421:Bacteria, Anaerobic / Q000145:classification* / Q000201:enzymology* / Q000235:genetics / Q000302:isolation & purification; D002087:Butyrates / Q000378:metabolism*; D015256:Coenzyme A-Transferases / Q000378:metabolism; D003106:Colon / Q000382:microbiology*; D004275:DNA, Ribosomal / Q000032:analysis; D017753:Ecosystem; D006801:Humans; D008969:Molecular Sequence Data; D010709:Phosphate Acetyltransferase / Q000378:metabolism; D017851:Phosphotransferases (Carboxyl Group Acceptor) / Q000378:metabolism*; D016133:Polymerase Chain Reaction; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D017422:Sequence Analysis, DNA
chemical_list: D002087:Butyrates; D004275:DNA, Ribosomal; D012336:RNA, Ribosomal, 16S; D010709:Phosphate Acetyltransferase; D017851:Phosphotransferases (Carboxyl Group Acceptor); C019285:butyrate kinase; D015256:Coenzyme A-Transferases; C019803:butyryl-CoA acetoacetate CoA transferase