Isolation and characterization of mutants of Aspergillus niger deficient in extracellular proteases

Autor: C.A.M.J.J. van den Hondel, I. E. Mattern, J.M. van Noort, I. N. Roberts, P. van den Berg, David B. Archer
Rok vydání: 1992
Předmět:
Zdroj: Molecular and General Genetics MGG. 234:332-336
ISSN: 1432-1874
0026-8925
Popis: 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, AB1.18, 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.
Databáze: OpenAIRE
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