TY - JOUR
T1 - Molecular details of a starch utilization pathway in the human gut symbiont Eubacterium rectale
AU - Cockburn, Darrell W.
AU - Orlovsky, Nicole I.
AU - Foley, Matthew H.
AU - Kwiatkowski, Kurt J.
AU - Bahr, Constance M.
AU - Maynard, Mallory
AU - Demeler, Borries
AU - Koropatkin, Nicole M.
N1 - Publisher Copyright:
© 2014 John Wiley & Sons Ltd.
PY - 2015/1/1
Y1 - 2015/1/1
N2 - Summary: Eubacterium rectale is a prominent human gut symbiont yet little is known about the molecular strategies this bacterium has developed to acquire nutrients within the competitive gut ecosystem. Starch is one of the most abundant glycans in the human diet, and E.rectale increases in vivo when the host consumes a diet rich in resistant starch, although it is not a primary degrader of this glycan. Here we present the results of a quantitative proteomics study in which we identify two glycoside hydrolase 13 family enzymes, and three ABC transporter solute-binding proteins that are abundant during growth on starch and, we hypothesize, work together at the cell surface to degrade starch and capture the released maltooligosaccharides. EUR_21100 is a multidomain cell wall anchored amylase that preferentially targets starch polysaccharides, liberating maltotetraose, whereas the membrane-associated maltogenic amylase EUR_01860 breaks down maltooligosaccharides longer than maltotriose. The three solute-binding proteins display a range of glycan-binding specificities that ensure the capture of glucose through maltoheptaose and some α1,6-branched glycans. Taken together, we describe a pathway for starch utilization by E.rectaleDSM 17629 that may be conserved among other starch-degrading Clostridium cluster XIVa organisms in the human gut.
AB - Summary: Eubacterium rectale is a prominent human gut symbiont yet little is known about the molecular strategies this bacterium has developed to acquire nutrients within the competitive gut ecosystem. Starch is one of the most abundant glycans in the human diet, and E.rectale increases in vivo when the host consumes a diet rich in resistant starch, although it is not a primary degrader of this glycan. Here we present the results of a quantitative proteomics study in which we identify two glycoside hydrolase 13 family enzymes, and three ABC transporter solute-binding proteins that are abundant during growth on starch and, we hypothesize, work together at the cell surface to degrade starch and capture the released maltooligosaccharides. EUR_21100 is a multidomain cell wall anchored amylase that preferentially targets starch polysaccharides, liberating maltotetraose, whereas the membrane-associated maltogenic amylase EUR_01860 breaks down maltooligosaccharides longer than maltotriose. The three solute-binding proteins display a range of glycan-binding specificities that ensure the capture of glucose through maltoheptaose and some α1,6-branched glycans. Taken together, we describe a pathway for starch utilization by E.rectaleDSM 17629 that may be conserved among other starch-degrading Clostridium cluster XIVa organisms in the human gut.
UR - http://www.scopus.com/inward/record.url?scp=84920703276&partnerID=8YFLogxK
U2 - 10.1111/mmi.12859
DO - 10.1111/mmi.12859
M3 - Article
C2 - 25388295
AN - SCOPUS:84920703276
SN - 0950-382X
VL - 95
SP - 209
EP - 230
JO - Molecular Microbiology
JF - Molecular Microbiology
IS - 2
ER -