Membrane mutation affecting energy-linked functions in Escherichia coli K 12.

A small-colony forming variant of Escherichia coli with a mutation in the ncf gene was analysed. The alternation of the protein composition in the cytoplasmic membrane and the interaction with K and E group colicins indicated a membrane mutation. The effect of this mutation on some membrane-bound processes, the activity of Mg2+-activated ATPase, the growth on different carbon sources and the active transport of amino acids, is described. This mutation does not exert any effect on the electron transport system.