ISSN:
1617-4623
Keywords:
Aspergillus niger
;
Extracellular proteases
;
Protease-deficient mutants
;
Parasexual analysis
;
Aspergillopepsin A
;
Heterologous protein degradation
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Summary In the present study, the extracellular protease activity in a strain of the filamentous fungus Aspergillus niger was investigated and mutant strains deficient in the production of extracellular proteases were isolated. The major protease, which is responsible for 80–85% of the total activity, is aspergillopepsin A, a protein of ca. 43 kDa, the activity of which is inhibited by pepstatin. In addition, a second protease, aspergillopepsin B, is produced, which is much less sensitive to inhibition by pepstatin. Several protease-deficient mutants were obtained by in vivo UV mutagenesis. In addition, a mutant lacking aspergillopepsin A was constructed by an in vitro gene replacement strategy. In this mutant, AB1.1, the entire coding region of the gene for aspergillopepsin A (pepA) is deleted. In three UV-induced mutants, aspergillopepsin A is also missing. One of these mutants, AB 1.18, is mutated in the pepA gene, which is located on chromosome I. One of the other mutants, AB1.13, which has only 1–2 % of the extracellular protease activity in the parent strain, is deficient in both aspergillopepsin A and aspergillopepsin B. The mutation involved, prt-13, has been localized to chromosome VI, and is probably a mutation in a regulatory gene. Another mutation involved in loss of protease function, prt-39, is located on chromosome VIII. Degradation of various heterologous proteins in culture media of the mutants is reduced but, even in strain AB1.13, not completely abolished.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00283855
Permalink
