Nitrogenaseless Mutants of Azotobacter vinelandii

Nitrogenaseless Mutants of Azotobacter vinelandii

Mutants of Azotobacter which grow normally on excess ammonia under a variety of conditions and which grow slowly or not at all on atmospheric nitrogen have been isolated. Extracts of these strains have low or no detectable nitrogenase activity. There are three classes of mutants. Cell-free preparati...

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Bibliographic Details
Published in:Proceedings of the National Academy of Sciences - PNAS Vol. 65; no. 1; pp. 74 - 80
Main Authors: Sorger, George J., Trofimenkoff, Diane
Format: Journal Article
Language:English
Published: United States National Academy of Sciences of the United States of America 01-01-1970
National Acad Sciences
Subjects:
Ammonia
Atmospherics
Azotobacter
Azotobacter - enzymology
Azotobacter - metabolism
Azotobacter vinelandii
Bacteriophages
Biological Sciences: Microbiology
Cell-Free System
Ferredoxins - metabolism
Genetic Complementation Test
Genetics, Microbial
Microbial Sensitivity Tests
Microbiology
Molybdenum
Molybdenum - metabolism
Mutation
Nitrogen
Nitrogen Fixation
Oxidoreductases
Solids
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Summary:Mutants of Azotobacter which grow normally on excess ammonia under a variety of conditions and which grow slowly or not at all on atmospheric nitrogen have been isolated. Extracts of these strains have low or no detectable nitrogenase activity. There are three classes of mutants. Cell-free preparations of members of the first class possess an enhancement factor (EF+) which stimulates wild-type nitrogenase in vitro. Homogenates of members of the second class possess an enhanceable factor (EF-) which complements in vitro with extracts of the first class of mutants to give substantial nitrogenase activity. Preparations of members of the third class contain neither EF+ nor EF- activity. EF+ and EF- are repressed by the same conditions that repress nitrogenase. Molybdenum-deficient cells of the second class of mutants do not appear to contain EF- activity, but molybdenum deficient cells of the first class of mutants contain EF+. Because of these observations, EF+ is tentatively equated to azoferredoxin and EF- to molybdoferredoxin.
Bibliography:ObjectType-Article-1
SourceType-Scholarly Journals-1
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content type line 23
ISSN:0027-8424
1091-6490
DOI:10.1073/pnas.65.1.74