We have recently identified an antisense RNA (RNA alpha) that regulates the expression of the fatA iron transport gene encoding the outer membrane receptor for the iron-anguibactin complex. In this work, we demonstrate that RNA alpha also inhibits the expression of fatB, which encodes a 35 kDa iron transport protein and has domains homologous to other periplasmic transport proteins. The expression of fatA and fatB is repressed under iron-rich conditions, in which RNA alpha is induced. RNA alpha is homologous to two-thirds of the coding region of fatB. By cloning RNA alpha coding sequences immediately downstream of a tet promoter, we were able to obtain constitutive expression of the antisense RNA. The cloned region contains approximately 83% of the 650 nucleotide RNA alpha and is complementary to only 51% of the fatB mRNA but is still capable of causing a repression of the expression of the fatB gene. Our results in this work demonstrate that RNA alpha probably affects the stability of the fatB-specific mRNA.