TY - JOUR
T1 - Structure and Functional Analysis of ClbQ, an Unusual Intermediate-Releasing Thioesterase from the Colibactin Biosynthetic Pathway
AU - Guntaka, Naga Sandhya
AU - Healy, Alan R.
AU - Crawford, Jason M.
AU - Herzon, Seth B.
AU - Bruner, Steven D.
N1 - Funding Information:
Financial support from the National Science Foundation (Grant 1411991 to S.D.B) and the National Institutes of Health (Grant R01GM110506 to S.B.H. and Grant 1DP2-CA 186575 to J.M.C) is gratefully acknowledged. We are grateful to the staff of LS-CAT 21-ID-G beamline at Argonne National Laboratory, IL, U.S.A., for assistance with X-ray data collection and processing. We also thank W. H. Chen for assistance in the crystal structure refinement. We thank E. Trautman for synthesizing N-myristoyl-D-Asn-SNAC.
Publisher Copyright:
© 2017 American Chemical Society.
PY - 2017/10/20
Y1 - 2017/10/20
N2 - Colibactin is a genotoxic hybrid nonribosomal peptide/polyketide secondary metabolite produced by various pathogenic and probiotic bacteria residing in the human gut. The presence of colibactin metabolites has been correlated to colorectal cancer formation in several studies. The specific function of many gene products in the colibactin gene cluster can be predicted. However, the role of ClbQ, a type II editing thioesterase, has not been established. The importance of ClbQ has been demonstrated by genetic deletions that abolish colibactin cytotoxic activity, and recent studies suggest an atypical role in releasing pathway intermediates from the assembly line. Here we report the 2.0 Å crystal structure and biochemical characterization of ClbQ. Our data reveal that ClbQ exhibits greater catalytic efficiency toward acyl-thioester substrates as compared to precolibactin intermediates and does not discriminate among carrier proteins. Cyclized pyridone-containing colibactins, which are off-pathway derivatives, are not viable substrates for ClbQ, while linear precursors are, supporting a role of ClbQ in facilitating the promiscuous off-loading of premature precolibactin metabolites and novel insights into colibactin biosynthesis.
AB - Colibactin is a genotoxic hybrid nonribosomal peptide/polyketide secondary metabolite produced by various pathogenic and probiotic bacteria residing in the human gut. The presence of colibactin metabolites has been correlated to colorectal cancer formation in several studies. The specific function of many gene products in the colibactin gene cluster can be predicted. However, the role of ClbQ, a type II editing thioesterase, has not been established. The importance of ClbQ has been demonstrated by genetic deletions that abolish colibactin cytotoxic activity, and recent studies suggest an atypical role in releasing pathway intermediates from the assembly line. Here we report the 2.0 Å crystal structure and biochemical characterization of ClbQ. Our data reveal that ClbQ exhibits greater catalytic efficiency toward acyl-thioester substrates as compared to precolibactin intermediates and does not discriminate among carrier proteins. Cyclized pyridone-containing colibactins, which are off-pathway derivatives, are not viable substrates for ClbQ, while linear precursors are, supporting a role of ClbQ in facilitating the promiscuous off-loading of premature precolibactin metabolites and novel insights into colibactin biosynthesis.
UR - http://www.scopus.com/inward/record.url?scp=85031943738&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85031943738&partnerID=8YFLogxK
U2 - 10.1021/acschembio.7b00479
DO - 10.1021/acschembio.7b00479
M3 - Article
C2 - 28846367
AN - SCOPUS:85031943738
SN - 1554-8929
VL - 12
SP - 2598
EP - 2608
JO - ACS Chemical Biology
JF - ACS Chemical Biology
IS - 10
ER -