TY - JOUR
T1 - A Periplasmic Binding Protein for Pyrroloquinoline Quinone
AU - Ho, Jackson V.
AU - Cotruvo, Joseph A.
N1 - Funding Information:
*E-mail: [email protected]. ORCID Jackson V. Ho: 0000-0002-6195-1235 Joseph A. Cotruvo, Jr.: 0000-0003-4243-8257 Funding J.A.C. acknowledges the Penn State Department of Chemistry, the Huck Institutes for the Life Sciences, and a Louis Martarano Career Development Professorship for funding. The ITC work was supported by NSF-MRI award DBI-0922974. Notes The authors declare no competing financial interest.
Publisher Copyright:
© 2019 American Chemical Society.
Copyright:
Copyright 2019 Elsevier B.V., All rights reserved.
PY - 2019/6/11
Y1 - 2019/6/11
N2 - Pyrroloquinoline quinone (PQQ) is an essential redox cofactor in bacterial calcium- and lanthanide-dependent alcohol dehydrogenases. Although certain bacteria are known to synthesize and secrete PQQ, little is known about trafficking of this cofactor within and between cells. Here, we show that a previously uncharacterized periplasmic (solute) binding protein from Methylobacterium extorquens AM1, here renamed PqqT, binds 1 equiv of PQQ with high affinity (Kd = 50 nM). UV-visible and spectrofluorometric titrations establish that PqqT binds an unhydrated form of PQQ with distinct spectral features from the cofactor in free solution. To our knowledge, PqqT is the first solute-binding protein identified for PQQ and the first protein implicated in cellular trafficking of the cofactor. We propose that PqqT, which is encoded adjacent to a putative ATP-binding cassette transporter in the M. extorquens genome, is involved in uptake of exogenous PQQ to supplement endogenous cofactor biosynthesis. These results support the emerging importance of PQQ transfer within microbial and microbe-host communities.
AB - Pyrroloquinoline quinone (PQQ) is an essential redox cofactor in bacterial calcium- and lanthanide-dependent alcohol dehydrogenases. Although certain bacteria are known to synthesize and secrete PQQ, little is known about trafficking of this cofactor within and between cells. Here, we show that a previously uncharacterized periplasmic (solute) binding protein from Methylobacterium extorquens AM1, here renamed PqqT, binds 1 equiv of PQQ with high affinity (Kd = 50 nM). UV-visible and spectrofluorometric titrations establish that PqqT binds an unhydrated form of PQQ with distinct spectral features from the cofactor in free solution. To our knowledge, PqqT is the first solute-binding protein identified for PQQ and the first protein implicated in cellular trafficking of the cofactor. We propose that PqqT, which is encoded adjacent to a putative ATP-binding cassette transporter in the M. extorquens genome, is involved in uptake of exogenous PQQ to supplement endogenous cofactor biosynthesis. These results support the emerging importance of PQQ transfer within microbial and microbe-host communities.
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U2 - 10.1021/acs.biochem.9b00358
DO - 10.1021/acs.biochem.9b00358
M3 - Article
C2 - 31140787
AN - SCOPUS:85066467167
SN - 0006-2960
VL - 58
SP - 2665
EP - 2669
JO - Biochemistry
JF - Biochemistry
IS - 23
ER -