The rpoD1 Gene Product Is a Principal Sigma Factor of RNA Polymerase in Microcystis aeruginosa K-81
- 1 October 1996
- journal article
- research article
- Published by Oxford University Press (OUP) in The Journal of Biochemistry
- Vol. 120 (4) , 752-758
- https://doi.org/10.1093/oxfordjournals.jbchem.a021475
Abstract
We performed molecular characterization of the RpoD1 protein encoded by the rpoDl gene isolated from a cyanobacterium, Microcystis aeruginosa K-81. The deduced amino acid sequence (416 aa, 48,871 Da) of RpoD1 exhibited extensive similarity to those of proteins of the eubacterial RpoD family (Escherichia coli σ70 homologs). We overproduced and purified RpoDl (54 kDa) from E. coli. Biological and biochemical analyses suggested that RpoDl has a function homologous to that of E. coli σ70 as follows: (i) the RpoD1 protein complemented an rpoD mutant of E. coli strain YN543 (rpoD285) and (ii) the heterologous RNA polymerase holoenzyme reconstituted from the E. coli core enzyme and recombinant RpoDl was specifically transcribed from E. coli promoters. Furthermore, Western blot analysis with antiserum against Synechococcus sp. strain PCC 7942 RpoDl (a principal sigma factor of the σ70 type) indicated that M. aeruginosa K-81 RpoDl (σA1 is the principal σ factor, which is a major component of the σ1 subunit on exponential cell growth.Keywords
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