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Proteins and Carbs – The Balanced Diet of a Complex and Unusual Enzyme Family
Author(s) -
Boraston Alisdair,
Noach Ilit,
FickoBlean Elizabeth,
Stuart Christopher,
Brochu Denis,
Gilbert Michel
Publication year - 2016
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.30.1_supplement.506.3
Subject(s) - mucin , bacteroides thetaiotaomicron , glycoprotein , proteases , protease , bacteria , microbiology and biotechnology , biology , biochemistry , glycan , metalloproteinase , mucus , enzyme , bacteroides , clostridium perfringens , genetics , ecology
Many host‐adapted bacteria have the capability to colonize mucosal layers. To do so, these bacteria have often developed the capacity to breakdown the mucin component of the protective layers that cover epithelial cells. As mucins are glycoproteins that are up to 80% carbohydrate by mass the most common feature of bacterial mucin degrading systems is an arsenal of enzymes that breakdown carbohydrates. However, how such bacteria may target the protein backbone of mucins remains a poorly investigated question. We have identified mucin‐degrading proteins in Clostridium perfringens, Bacteroides thetaiotaomicron , and Pseudomonas aeruginosa , which are all host‐adapted a bacteria notable their ability to colonize the mucus rich environments of human and animal tissues. These proteins are zinc‐metalloproteases and thus cleave the peptide backbone. Remarkably, our structural and functional analyses of these enzymes reveal that O‐linked glycans accommodated in the zinc‐metalloprotease active site is a determinant of specificity, and this is dependent on the particular protease. This work provides the first detailed molecular insight into a large family of glycoproteases found in host‐adapted microbes and highlights the potential complexity of substrate specificity in glycoprotein specific proteases.