Affiliation:
1. Department of Soil, Water, and Environmental Science
2. Department of Biochemistry and Molecular Biophysics, University of Arizona, Tucson, Arizona 85721
Abstract
ABSTRACT
The genome sequences of several pseudomonads have revealed a gene cluster containing genes for a two-component heavy metal histidine sensor kinase and response regulator upstream of
cinA
and
cinQ
, which we show herein to encode a copper-containing azurin-like protein and a pre-Q
0
reductase, respectively. In the presence of copper,
Pseudomonas putida
KT2440 produces the CinA and CinQ proteins from a bicistronic mRNA. UV-visible spectra of CinA show features at 439, 581, and 719 nm, which is typical of the plastocyanin family of proteins. The redox potential of the protein was shown to be 456 ± 4 mV by voltametric titrations. Surprisingly, CinQ is a pyridine nucleotide-dependent nitrile oxidoreductase that catalyzes the conversion of pre-Q
0
to pre-Q
1
in the nucleoside queuosine biosynthetic pathway. Gene disruptions of
cinA
and
cinQ
did not lead to a significant increase in the copper sensitivity of
P. putida
KT2440 under the conditions tested. Possible roles of CinA and CinQ to help pseudomonads adapt and survive under prolonged copper stress are discussed.
Publisher
American Society for Microbiology
Subject
Molecular Biology,Microbiology
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