Three classes of Hup mutants of were obtained by -methyl-′-nitro--nitrosoguanidine mutagenesis and screening by HH uptake: (1) those with no discernible H-uptake or H-evolving activity, (2) those showing no uptake but some H production and (3) those leaky for both activities. One mutant strain, MCD-124, expressed hydrogenase activity similar to the solubilized wild-type enzyme in O sensitivity, sedimenting behaviour and pH optimum. All the other mutants were probably mutated in the hydrogenase structural or processing (methylene blue) genes rather than in genes for hydrogenase-linked respiratory proteins. Four mutants chosen from the first category were complemented for hydrogenase activity by conjugation with carrying plasmid pHU1 containing hydrogenase genes. A pHU1 transconjugant of strain MCD-124, on the other hand, did not express any additional hydrogenase activity.


Article metrics loading...

Loading full text...

Full text loading...

This is a required field
Please enter a valid email address
Approval was a Success
Invalid data
An Error Occurred
Approval was partially successful, following selected items could not be processed due to error