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Multiple pqq A genes respond differently to environment and one contributes dominantly to pyrroloquinoline quinone synthesis
Author(s) -
Ge Xin,
Wang Wenxi,
Du Baohua,
Wang Jianhua,
Xiong Xianghua,
Zhang Weicai
Publication year - 2015
Publication title -
journal of basic microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.58
H-Index - 54
eISSN - 1521-4028
pISSN - 0233-111X
DOI - 10.1002/jobm.201300037
Subject(s) - pyrroloquinoline quinone , gene , cofactor , biochemistry , bacteria , overproduction , plasmid , promoter , biology , operon , chemistry , microbiology and biotechnology , genetics , enzyme , gene expression , escherichia coli
Pyrroloquinoline quinone is the third redox cofactor after nicotinamide and flavin in bacteria, and its biosynthesis pathway comprise five steps initiated from a precursor peptide PqqA coded by pqq A gene. Methylovorus sp. MP688 is equipped with five copies of pqq A genes. Herein, the transcription of pqq A genes under different conditions by real‐time quantitative PCR and β‐galactosidase reporter genes are reported. Multiple pqq A genes were proved to play significant roles and contribute differently in PQQ synthesis. pqq A1, pqq A2, and pqq A4 were determined to be dominantly transcribed over the others, and correspondingly absence of any of the three genes caused a decrease in PQQ synthesis. Notably, pqq A was up‐regulated in low pH and limited oxygen environment, and it is pqq A2 promoter that could be induced when bacteria were transferred from pH 7.0 to pH 5.5. Deletion analysis revealed a region within pqq A2 promoter inhibiting transcription. PQQ concentration was increased by overexpression of pqq genes under control of truncated pqq A2 promoter. The results not only imply there exist negative transcriptional regulators for pqq A2 but also provide us a new approach to achieve higher PQQ production by deleting the target binding sequence.