Physico-chemical interaction of mycobacillin with Aspergillus niger protoplast membrane, the site of its action.

Abstract

Mycobacillin partially quenched the strong fluorescence when 1-anilino naphthalene 8-sulfonate (ANS) was added to protoplast or plasma membrane but is without any effect on weak fluorescence when added to cell-free extract. There are two classes of ANS binding sites on protoplast or plasma membrane of which one class is sensitive to mycobacillin, being competitively abolished by it. Mycobacillin also non-competitively inhibits the binding of pyrene, a lipid specific probe. Thus it follows from the inhibition by mycobacillin of ANS or pyrene binding to protoplast or plasma membrane that the site of action of the antibiotic is located in the plasma membrane. Interaction between mycobacillin and the plasma membrane is physico-chemical in nature.