%0 Journal Article %A Derouiche, Rahmona %A Zeder-Lutz, Gabrielle %A Bénédetti, Hélène %A Gavioli, Marthe %A Rigal, Alain %A Lazdunski, Claude %A LloubèAs, Roland %T Binding of colicins A and E1 to purified ToIA domains %D 1997 %J Microbiology, %V 143 %N 10 %P 3185-3192 %@ 1465-2080 %R https://doi.org/10.1099/00221287-143-10-3185 %K protein interactions %K colicins %K Tol proteins %I Microbiology Society, %X Colicins are divided into two groups according to the proteins required for their import into sensitive bacteria. The Tol and TonB pathways are involved in import of group A and group B colicins respectively. Because previous analyses have shown that colicin E1 and colicin A (two group A colicins) interact in vitro with the C-terminal domain of TolA (TolAIII) while colicin B (group B colicin) does not, attention was focused on these interactions with purified proteins. TolA has been described as a three-domain protein with an N-terminal inner-membrane anchor and a long periplasmic region formed by two domains (TolAII and TolAIII). TolAIII, TolAII and TolAII-III soluble domains with an N-terminal hexa-histidine extension were purified. The interactions of colicins with the purified TolA domains were analysed by overlay Western blotting, which indicated that both N-terminal domains of colicins A and E1 interacted with TolAIII, while a gel shift procedure detected no interaction with colicin E1. The binding kinetic values of the N-terminal domains of colicins A and E1 to TolAIII were estimated by surface plasmon resonance and were shown to be similar. %U https://www.microbiologyresearch.org/content/journal/micro/10.1099/00221287-143-10-3185