Sequences and characterization of hupU and hupV genes of Bradyrhizobium japonicum encoding a possible nickel-sensing complex involved in hydrogenase expression
| Autor: | Changlin Fu, Robert J. Maier, L. K. Black |
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| Rok vydání: | 1994 |
| Předmět: |
Hydrogenase
Operon Protein subunit Immunoblotting Molecular Sequence Data Restriction Mapping Repressor Microbiology Gene Expression Regulation Enzymologic Homology (biology) Nickel Rhizobiaceae Amino Acid Sequence Molecular Biology Rhodobacter Base Sequence Sequence Homology Amino Acid biology Gene Expression Regulation Bacterial Sequence Analysis DNA biology.organism_classification Molecular biology Open reading frame Biochemistry Genes Bacterial Mutation Research Article Signal Transduction Bradyrhizobium japonicum |
| Zdroj: | Journal of Bacteriology. 176:7102-7106 |
| ISSN: | 1098-5530 0021-9193 |
| Popis: | A 2.7-kb DNA fragment of Bradyrhizobium japonicum previously shown to be involved in hydrogenase expression has been sequenced. The area is located just upstream of the hupSLCDF operon and was found to contain two open reading frames, designated hupU and hupV; these encode proteins of 35.4 and 51.8 kDa, respectively. These proteins are homologous to Rhodobacter capsulatus HupU, a possible repressor of hydrogenase expression in that organism. B. japonicum HupU is 54% identical to the N terminus of R. capsulatus HupU, and HupV is 50% identical to the C terminus of R. capsulatus HupU. HupU and HupV also show homology to the [Ni-Fe] hydrogenase small and large subunits, respectively. Notably, HupV contains the probable nickel-binding sites RxCGxC and DPCxxCxxH, which are located in the N- and C-terminal portions, respectively, of the large subunit of hydrogenases. Hydrogenase activity assays, immunological assays for hydrogenase subunits, and beta-galactosidase assays on mutant strain JHCS2 (lacking a portion of HupV) were all indicative that HupV is necessary for transcriptional activation of hydrogenase. A physiological role as a possible nickel- or other environmental (i.e., oxygen or hydrogen)-sensing complex is proposed for HupU and HupV. |
| Databáze: | OpenAIRE |
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