Abou-Sabé M, Ratner P L
Biochim Biophys Acta. 1977 Jun 17;476(4):321-32. doi: 10.1016/0005-2787(77)90296-9.
Merodiploid complementation analysis of the constitutive synthesis of the D-ribokinase and the D-ribose permease in Escherichia coli B/r has shown that the constitutive D-ribose operon is genetically controlled by a transdominant regulatory gene closely linked to the D-ribokinase and D-ribose permease structural genes. The regulatory mechanism for this operon shows no requirement for operator-repressor interaction, rather a truly positive control mechanism and thus suggests an extension of the operon model in its application to constitutive enzyme regulation in bacteria.
