JB
Home Help [Feedback] [For Subscribers] [Archive] [Search] [Contents]
This Article
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow Copyright Information
Right arrow Books from ASM Press
Right arrow MicrobeWorld
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Happe, T.
Right arrow Articles by Böhme, H.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Happe, T.
Right arrow Articles by Böhme, H.

Journal of Bacteriology, March 2000, p. 1624-1631, Vol. 182, No. 6
0021-9193/00/$04.00+0
Copyright © 2000, American Society for Microbiology. All rights reserved.

Transcriptional and Mutational Analysis of the Uptake Hydrogenase of the Filamentous Cyanobacterium Anabaena variabilis ATCC 29413

Thomas Happe,* Kathrin Schütz, and Herbert Böhme

Botanisches Institut der Universität Bonn, D-53115 Bonn, Germany

Received 1 September 1999/Accepted 21 December 1999

A 10-kb DNA region of the cyanobacterium Anabaena variabilis ATCC 29413 containing the structural genes of the uptake hydrogenase (hupSL) was cloned and sequenced. In contrast to the hupL gene of Anabaena sp. strain PCC 7120, which is interrupted by a 10.5-kb DNA fragment in vegetative cells, there is no programmed rearrangement within the hupL gene during the heterocyst differentiation of A. variabilis. The hupSL genes were transcribed as a 2.7-kb operon and were induced only under nitrogen-fixing conditions, as shown by Northern blot experiments and reverse transcriptase PCR. Primer extension experiments with a fluorescence-labeled oligonucleotide primer confirmed these results and identified the 5' start of the mRNA transcript 103 bp upstream of the ATG initiation codon. A consensus sequence in the promoter that is recognized by the fumarate nitrate reductase regulator (Fnr) could be detected. The hupSL operon in A. variabilis was interrupted by an interposon deletion (mutant strain AVM13). Under N2-fixing conditions, the mutant strain exhibited significantly increased rates in H2 accumulation and produced three times more hydrogen than the wild type. These results indicate that the uptake hydrogenase is catalytically active in the wild type and that the enzyme reoxidizes the H2 developed by the nitrogenase. The Nif phenotype of the mutant strain showed a slight decrease of acetylene reduction compared to that of the wild type.

* Corresponding author. Mailing address: Botanisches Institut der Universität Bonn, Karlrobert-Kreiten-Str. 13, D-53115 Bonn, Germany. Phone: 49-228-73-5516. Fax: 49-228-73-1697. E-mail: t.happe{at}uni-bonn.de.

Journal of Bacteriology, March 2000, p. 1624-1631, Vol. 182, No. 6
0021-9193/00/$04.00+0
Copyright © 2000, American Society for Microbiology. All rights reserved.


This article has been cited by other articles:



Home Help [Feedback] [For Subscribers] [Archive] [Search] [Contents]
Appl. Environ. Microbiol. Infect. Immun. Eukaryot. Cell
Mol. Cell. Biol. J. Virol. Microbiol. Mol. Biol. Rev.
ALL ASM JOURNALS

Copyright © 2000 by the American Society for Microbiology. All rights reserved.